This work was supported by the National Institute of Health grant R24OD018546 (to L.Y.P. and S.G.). The authors would like to thank Weizhe Li, Ph.D., for the help in surgical procedures, Amanda Branch Woods, B.S., Yan Cheng for immunohistology, UNMC flow cytometry research facility members Director Phillip Hexley, Ph.D., Victoria B. Smith, B.S., and Samantha Wall, B.S., UNMC advanced microscopy core facility members Janice A. Taylor, B.S., and James R. Talaska, B.S., for the technical support. The authors acknowledge Drs. Mamoru Ito and Hiroshi Suemizu from CIEA for providing TK-NOG mice and Dr. Joachim Baumgart for providing treosulfan. The authors thank Dr. Adrian Koesters, UNMC, for her editorial contribution to the manuscript.

This protocol has been approved by the Institutional Animal Care and Use Committee (IACUC)&#160;at the University of Nebraska Medical Center.
NOTE: Obtain approval from the local IACUC before performing experiments on animals.
1. Processing of Umbilical Cord Blood and the Isolation of Human HSPCs
<ol>
	<li>Perform all steps of the protocol under sterile conditions in laminar flow cabinets.</li>
	<li>Take umbilical cord blood (CB) collected in heparinized tubes and make the volume up to 35 mL by adding phosphate-buffered saline (PBS). Layer the sample on top of the lymphocytes separation medium (LSM) as illustrated in Figure 1 and centrifuge the LSM with the layered CB at 400 x g for 35 min at 4 &#176;C with no brakes. 
	NOTE: Dilute the blood carefully and gently to avoid mixing at the interface.&#160;</li>
	<li>Remove the top LSM and plasma layer carefully and transfer the white buffy coat interface to a new tube using a transfer pipette.</li>
	<li>Resuspend the buffy coat in 30 - 40 mL of ice-cold buffer (PBS + 0.5% bovine serum albumin [BSA] + 2 mM ethylenediaminetetraacetic acid [EDTA]). Using a pipette, combine 20 &#181;L of the cell suspension with 20 &#181;L of 0.4% trypan blue and pipette 10 &#181;L of the mixture into the outer opening of either of the two chambers of a counting slide and insert the slide in an automated cell counter to count the cells. 
	NOTE: Use ice-cold buffer in all steps, as it helps keep the cells viable.</li>
	<li>Centrifuge the cells at 300 x g for 10 min at 4 &#176;C and aspirate the supernatant carefully. Then, add 300 &#181;L of ice-cold buffer.</li>
	<li>Add 100 &#181;L of human Fc receptor blocking reagent and 100 &#181;L of monoclonal mouse anti-human CD34 antibody-conjugated microbeads for up to 1 x 108 cells (see the Table of Materials). Incubate for 30 min at 4 &#176;C, add 10 mL of ice-cold buffer to wash the cells, and centrifuge at 300 x g for 10 min at 4 &#176;C. 
	NOTE: Scale this up according to the cell number if more than 1 x 108 cells are present.</li>
	<li>Carefully remove the supernatant, resuspend the pellet in 500 &#181;L of buffer, and proceed with the magnetic separation step to enrich HSPCs.</li>
	<li>Place a positive selection LS column (see the Table of Materials) in the magnetic-activated cell sorting field and pass it through with 3 mL of buffer.</li>
	<li>Load the sample to the LS column that can entrap microbeads bound to human CD34+ in samples and allow it to flow under the influence of gravity into the collection tube.</li>
	<li>Wash the column 3x with buffer and collect the elute in the same collection tube of the CD34- fraction of cells.</li>
	<li>Plunge the column with 5 mL of buffer to elute the CD34+ cells into a new collection tube. Repeat the procedure to achieve a purity of &#62;90%.</li>
	<li>Count the eluted CD34+ cells using trypan blue dye in a hemocytometer. After counting, centrifuge the CD34+ cells at 300 x g for 5 min and discard the supernatant.</li>
	<li>Resuspend the CD34+ cells in 25 &#181;L of PBS for an injection to be used immediately in transplantation&#160;or cryopreserve the cells at a concentration of 1-2 million/mL in freezing medium (Roswell Park Memorial Institute medium [RPMI 1640 medium] + 50% fetal bovine serum (FBS) + 10% dimethyl sulfoxide [DMSO]) for further use in transplantation. 
	NOTE: Always recount viable cells before using them in transplantation.</li>
	<li>To check the purity of the CD34+ elute, take 50 &#181;L of the suspension and incubate it with 10 &#181;L of PE-conjugated anti-human CD34 antibody for 30 min at 4 &#176;C. After the antibody incubation, wash the stained cells with PBS, resuspend them in 100 &#181;L of PBS, and then, proceed to perform flow cytometry. Add an additional tube of cells with no antibody to design the gate in the flow cytometer.</li>
	<li>After acquisition, analyze the data by selecting the region of interest on a forward scatter (FSC) and side scatter (SSC) plot, followed by gating for single cells on FSC-area and FSC-height plots. Gate CD34-positive cells on single cells in the PE channel and SSC-area plot.</li>
</ol>
2. Preparation of Human Hepatocytes for Transplantation
<ol>
	<li>Remove the cryopreserved hepatocytes from the liquid nitrogen, quickly submerge the vial in the water bath, and thaw for approximately 90 - 120 s.</li>
	<li>Remove the vial cap and pour the thawed hepatocytes into the 50 mL conical tube of the warmed thawing medium.</li>
	<li>Suspend the cells by rocking the 50 mL tube by hand for a few seconds. 
	NOTE: Do not vortex the tube.</li>
	<li>Pellet the cells at 100 x g for 8 min at room temperature.Wash the pelleted cells in PBS with 0.1% BSA and pool them with either fresh or thawed HSPCs (ratio 10:1) in PBS in a final volume of 80 &#181;L/mouse.</li>
</ol>
3. Animal Handling, Screening, Genotyping, and Treatment for Human HSPC and Hepatocyte Transplantation
<ol>
	<li>Animal handling
	<ol>
		<li>As a result of severe immunodeficiency, breed, house, and handle TK-NOG mice under aseptic conditions.</li>
		<li>Always wear a lab coat, gloves, shoe covers, and a face mask to prevent infection with potentially pathogenic microorganisms.</li>
		<li>Use sterile gloves and instruments for surgery and handle the animals aseptically throughout the surgery.</li>
	</ol>
	</li>
	<li>Selecting TK-NOG mice for the experiment
	<ol>
		<li>Maintain the TK-NOG strain colony by breeding female TK-NOG mice with male non-TK-NOG littermates and select transgenic offspring by genotyping. 
		NOTE: Perform genotyping (see step 3.3) to determine the presence or absence of the transgene in newborn male and female mice at the time of weaning.</li>
		<li>Select males at 6 - 8 weeks of age for transplantation due to their high sensitivity to the GCV-mediated depletion of HSV-TK transgene-expressing hepatocytes21.</li>
		<li>Ear-tag the mice at the time of weaning or surgery to ease identification. Note down the weight and health status of the animals.</li>
	</ol>
	</li>
	<li>Genotyping for the presence of the HSV-TK transgene using quantitative real-time polymerase chain reaction
	<ol>
		<li>Perform genotyping at the time of weaning (usually at 3 - 4 weeks of age). For genotyping, cut a piece of the mouse ear in a laminar flow biological safety cabinet to maintain sterility and extract genomic DNA by using a genomic DNA isolation kit.</li>
		<li>Amplify genomic DNA extracted from ear piece&#160;in a 20 &#181;L reaction mixture to screen for HSV-TK transgene under control of human albumin promoter by adding 1 &#181;L of forward primer 5&#39;-CCATGCACGTCTTTATCCTGG-3&#39;, 1 &#181;L of reverse primer 5&#39;-TAAGTTGCAGCAGGGCGTC-3&#39;, 0.5 &#181;L of FAM probe 5&#8242;-FAM-AATCGCCCGCCGGCTGC-MGB-3&#39;, and 10 &#181;L of master mix on a real-time polymerase chain reaction (PCR) instrument22.</li>
		<li>Set the real-time PCR settings as follows: 60 &#176;C for 30 s (preread stage), 95 &#176;C for 10 min (hold stage), 40 cycles of 95 &#176;C for 15 s and 60 &#176;C for 1 min (PCR stage), and 60 &#176;C for 30 s (postread stage). 
		NOTE: A cycle of threshold (Ct) below 22 is considered positive for HSV-TK transgene.</li>
	</ol>
	</li>
	<li>Treatment using ganciclovir and treosulfan
	<ol>
		<li>Using 27 G needle, inject the TK-NOG mice with intraperitoneal GCV injections (6 mg/kg) 2x a day at day 7 and at day 5 in 100 &#181;L of saline before surgery to deplete the mice&#39;s transgenic parenchymal cells (as shown in the experimental strategy in Figure 2)23.</li>
		<li>On days 3, 2, and 1 before the surgery, precondition mice with nonmyeloablative intraperitoneal doses of treosulfan (1.5 g/kg/day) in 100 &#181;L of saline, using a 27 G needle.</li>
		<li>One day before the surgery, draw two to three drops (~100 &#181;L) of blood from the submandibular vein by pricking it with a 5 mm lancet, and isolate the serum by centrifuging (1,500 x g for 10 min at 4 &#176;C) for the alanine aminotransferase (ALT) assay to assess the degree of liver damage.</li>
	</ol>
	</li>
	<li>Preparation for the surgery
	<ol>
		<li>Use clippers to shave the mouse&#39;s fur surrounding the incision site (at the left of the peritoneal wall) before surgery.</li>
		<li>Adjust the oxygen flow to 1 L/min and the isoflurane flow to 3% - 5% in an induction chamber using a mouse anesthesia machine. Place one mouse at a time in the induction chamber for anesthesia.</li>
		<li>Attach the one end of a sterile extension tube (with a holding capacity of 550 &#181;L of suspension; see the Table of Materials for specifications) to a 30 G needle and the other end to a 1 mL syringe.</li>
		<li>Fill the syringe with the suspension (80 &#181;L/mouse) of pooled HEPs and HSPCs (see section 2), fit the syringe in the notch of a repetitive dispensing pipette, and adjust the dispenser to dispense 10 &#181;L in each press.</li>
		<li>Once the mice are anesthetized (usually after 3 - 4 min), switch the isoflurane flow to the nose cone and reduce the isoflurane flow rate to 2% - 3%.</li>
	</ol>
	</li>
	<li>Intrasplenic transplantation of human HSPCs and hepatocytes in mice
	<ol>
		<li>Perform all surgery steps in a laminar flow cabinet under sterile conditions.</li>
		<li>Place a clean sterile drape over the working surface and scrub the left side of the body of each mouse with 10 % povidone-iodine followed by 70 % isopropyl alcohol, before making an incision.</li>
		<li>Make a small incision (~1 - 1.5 cm in length and 5 mm deep) in the skin, muscle, and peritoneum at the left of the peritoneal wall with Vanna&#39;s type scissors to enter the peritoneal cavity approximately 5 mm below the lower edge of the rib cage.</li>
		<li>Locate the spleen, pull it slightly with forceps to the operating area for easy access, and insert the 30 G needle into the lower pole of the spleen.</li>
		<li>Unlock the plunger of the dispensing pipette and dispense 10 &#181;L of the volume at a time, with a limit of 60 - 80 &#181;L per spleen. Retract the needle slowly and clip the spleen with ligating clips using a ligation applier.</li>
		<li>Push the spleen back into the body cavity with cotton-tipped applicators wetted with sterile PBS.&#160;</li>
		<li>Close the muscle layer of the abdominal wall using an absorbable suture&#160;interrupted suture pattern (not continuous). Accomplish skin closure with an interrupted suture pattern using non-absorbable sutures.</li>
		<li>Use warm water circulating pads to protect the mice from hypothermia after surgery.</li>
		<li>Remove non-absorbable sutures 10-14 days after surgery.</li>
	</ol>
	</li>
	<li>Postoperative care
	<ol>
		<li>When the transplanted animal wakens, inject analgesic buprenorphine (0.1 mg/kg) intraperitoneally, 2x a day for a consecutive 3 days.</li>
		<li>Observe the animals at least 1x a day until they return to normal physical conditions. 
		NOTE: Check each animal&#39;s body weight, since some mice may lose weight postsurgery. Mice typically regain their original weight in 1 to 2 weeks.</li>
	</ol>
	</li>
</ol>
4. Engraftment Validation of the Human Liver by ELISA and the Human Immune System by Flow Cytometry
NOTE: Evaluate the reconstitution of the human liver and immune system monthly, starting 1 month posttransplantation by enzyme-linked immunosorbent assay (ELISA) and flow cytometry, respectively.
<ol>
	<li>Collect blood samples from the submandibular vein using lancets in EDTA tubes, and centrifuge at 1,500 x g for 10 min at 4 &#176;C. Isolate serum to check human albumin levels to assess the engraftment efficiency of the mouse liver for transplanted human hepatocytes, using a human albumin ELISA quantitation set (see the Table of Materials) by following the manufacturer&#39;s instructions. 
	NOTE: Do not discard the pellet and use the pelleted cells for a flow cytometry analysis to evaluate the human immune system reconstitution.</li>
	<li>Resuspend the cell pellet without serum in 35 &#181;L of FACS buffer (PBS + 2% FBS) and stained with 5 &#181;L of mouse-specific CD45 (concentration 0.5 mg/mL), 5 &#181;L each of human-specific antibodies CD45 (0.1 mg/mL), CD3 (0.2 mg/mL), CD8 (0.1 mg/mL), and CD19 (0.5 mg/mL), and 20 &#181;L of CD4 (0.25 mg/mL) and CD14 (0.25 mg/mL) each for 30 min at 4 &#176;C, to check the development of a functional immune system from CD34+ HSPCs. 
	NOTE: Consider adding one additional tube of unstained cells to determine the gating of the stained cells.</li>
	<li>After incubation, transfer the stained suspension (~100 &#181;L) in a polystyrene round-bottom flow cytometry tube and use 2 mL of 1x lysis buffer (see the Table of Materials) by diluting 1 part of 10x lysis buffer with 9 parts of distilled water and incubating 10 - 15 min to lyse red blood cells. 
	NOTE: Observe turbidity to evaluate the red blood cell lysis. Once the sample becomes clear, the lysis is complete.</li>
	<li>After the lysis, add 3 mL of the FACS buffer in the tube and centrifuge at 300 x g at 4 &#176;C for 5 min to get a pellet. Repeat the washing by adding 3 mL of FACS buffer to the pellet and centrifuge at 300 x g at 4 &#176;C for 5 min.</li>
	<li>Fix the cells in freshly made 1% paraformaldehyde (PFA) and acquire stained cells on the flow cytometer, analyzed with flow software.</li>
	<li>For the analysis, select lymphocytes gating on an FSC/SSC plot, followed by single-cell gating on FSC-area/FSC-height.</li>
	<li>Further, gate for human-specific CD45 (hCD45) on the single-cell population and include mouse-specific CD45 (mCD45) for the exclusion of cells of murine origin. Strategize gating of the stained population based on the gating of unstained cells.</li>
	<li>Gate hCD45+ cells to determine the frequency of CD3+ T cells and CD19+ B cells. Gate T cells to determine CD4 and CD8 subsets. To evaluate monocytes, gate on hCD45 to determine CD14+ monocytes.</li>
</ol>
5. HIV Infection of TK-NOG Mice and Its Effect on the Human Liver and Immune System
<ol>
	<li>Handle the HIV-1 virus and all infected mice in a designated biosafety level 2&#160;facility. 
	CAUTION: Autoclave and discard all HIV-infected wastes in double biohazard bags. For safety reasons, wear cut-resistant gloves while handing HIV-infected mice.</li>
	<li>Wear personal protection equipment (PPE), including a disposable coverall gown, shoe covers, a face mask, and double gloves at all times while working with the virus.</li>
	<li>Select mice with a reconstitution of more than 15% of human CD45+ cells (tested in step 4.7) and with a presence of human albumin in the serum for HIV-1 infection (tested in step 4.1).</li>
	<li>Inject the mice with 1 x 103 to 1 x 104 tissue culture infectious doses 50 (TCID50) HIV-1ADA in a volume of 100 - 200 &#181;L per mouse, intraperitoneally.</li>
	<li>Euthanize the HIV-infected mice 5 weeks postinfection by using isoflurane (with an isoflurane vapor concentration&#160;of &#62;5%).</li>
	<li>After euthanizing the mice, collect blood in EDTA tubes by a cardiac puncture for the isolation of serum, to see the effect of HIV-1 on the liver by evaluating human-specific albumin levels by ELISA (see step 4.1) and blood cells to check for changes in the human immune cells using flow cytometry (see steps 4.2 - 4.8). 
	NOTE: Assess the peripheral viral load 5 weeks postinfection on a bioanalyzer to confirm if the mice are infected.</li>
	<li>After drawing blood, excise the liver from the euthanized mice.</li>
	<li>For the liver excision, expose the abdominal cavity by making an incision of 1.5 - 2 cm long and 0.5 cm deep in the skin, muscles, and peritoneum, from the xyphoid. Make a cut perpendicular to the spine between the liver and the diaphragm. Lift the liver and sever any membranes attaching it to the stomach and intestines.</li>
	<li>Collect and fix the liver in 4% paraformaldehyde overnight and follow a standard immunohistochemical protocol to evaluate the effect of HIV on CK18+ hepatocytes by using human-specific CK18 antibody8.</li>
</ol>

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R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Human+immunodeficiency+virus+infection+and+the+liver.">Human immunodeficiency virus infection and the liver.</a> World Journal of Hepatology. 4 (3), 91-98 (2012).</li><li>Bility, M. T., Li, F., Cheng, L., Su, L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Liver+immune-pathogenesis+and+therapy+of+human+liver+tropic+virus+infection+in+humanized+mouse+models.">Liver immune-pathogenesis and therapy of human liver tropic virus infection in humanized mouse models.</a> Journal of Gastroenterology and Hepatology. 28, 120-124 (2013).</li><li>Kong, L., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Low-level+HIV+infection+of+hepatocytes.">Low-level HIV infection of hepatocytes.</a> Virology Journal. 9, 1-7 (2012).</li><li>Dash, P. K., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Long-acting+nanoformulated+antiretroviral+therapy+elicits+potent+antiretroviral+and+neuroprotective+responses+in+HIV-1-infected+humanized+mice.">Long-acting nanoformulated antiretroviral therapy elicits potent antiretroviral and neuroprotective responses in HIV-1-infected humanized mice.</a> AIDS. 26 (17), 2135-2144 (2012).</li><li>Sun, S., Li, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Humanized+chimeric+mouse+models+of+hepatitis+B+virus+infection.">Humanized chimeric mouse models of hepatitis B virus infection.</a> International Journal of Infectious Diseases. 59, 131-136 (2017).</li><li>Shafritz, D. A., Oertel, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Model+systems+and+experimental+conditions+that+lead+to+effective+repopulation+of+the+liver+by+transplanted+cells.">Model systems and experimental conditions that lead to effective repopulation of the liver by transplanted cells.</a> The International Journal of Biochemistry &amp; Cell Biology. 43 (2), 198-213 (2011).</li><li>Almeida-Porada, G., Porada, C. D., Chamberlain, J., Torabi, A., Zanjani, E. D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Formation+of+human+hepatocytes+by+human+hematopoietic+stem+cells+in+sheep.">Formation of human hepatocytes by human hematopoietic stem cells in sheep.</a> Blood. 104 (8), 2582-2590 (2004).</li><li>Streetz, K. L., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Hepatic+parenchymal+replacement+in+mice+by+transplanted+allogeneic+hepatocytes+is+facilitated+by+bone+marrow+transplantation+and+mediated+by+CD4+cells.">Hepatic parenchymal replacement in mice by transplanted allogeneic hepatocytes is facilitated by bone marrow transplantation and mediated by CD4 cells.</a> Hepatology. 47 (2), 706-718 (2008).</li></ol>

The authors have nothing to disclose.

The liver is compromised and damaged in HIV-infected patients24. Experimental small animal models for studying human liver diseases in the presence of HIV-1 is extremely limited, despite the availability of a few cotransplanted animal models with CD34+ HSPCs and hepatocytes7,12,25. In in vitro experiments, hepatocytes are shown to have low-level HIV-1 infection26. Humanized mice that carry both types of human cells are a desirable model. The liver of mice reconstituted with only human immune system has been shown to be affected by HIV infection under the experimental depletion of human regulatory T cells20,27. However, the difference in immune and functional properties of mouse and human hepatocytes may underline the differences in their responses to HIV-1 and immune cells. In this review, a protocol is described to reconstitute both human immune system and liver and to address HIV-1-associated liver immunopathology, as observed in HIV-1-infected patients. TK-NOG male mice were selected due to their liver-selective high mRNA expression of HSV-TK transgene and the susceptibility of GCV toxicity to mouse transgenic liver21. Moreover, they can be maintained for long periods after transplantation without the use of exogenous drugs and do not develop spontaneous systemic diseases28. To establish human immune system and liver reconstitution, ablation of the mouse immune system and damage to mouse-specific liver cells are required and achieved using nonmyeloablative doses of treosulfan and GCV, as shown previously in TK-NOG male mice13,23. Mice are injected with GCV and treosulfan at the age of 6 - 8 weeks, as the expression of transgene and GCV-induced hepatic injury as assessed by ALT levels are optimal, then, for providing niche-to-transplanted human cells21. Mice showing ALT levels of &#62;200 U/L, but &#60;600 U/L, are usually selected for transplantation. Mice showing ALT levels of &#62;600 U/L are at a greater risk of death as human hepatocytes are not able to rescue the damaged mouse liver function.
Currently, dual humanization is shown by the transplantation of human CD34+ HSPCs and fetal liver cells; however, the manipulation of newborn animals creates technical problems13,14. HSPCs can be derived or isolated from multiple sources, such as fetal liver cells (FLCs), embryonic stem cells (ESCs), and CB. However, ethical issues constrain the use of ESCs and FLCs. CB has no such restriction and is a most useful alternative to obtain HSPCs, as well as being a precious source of primitive hematopoietic stem and progenitor cells that can reconstitute the functional immune system. Cord blood should not be older than one day when used to isolate HSPCs, as the yield of HSPCs is highly affected by age. The purity of the isolated HSPCs needs to be checked before cryopreserving the cells. The cross-contamination of CD3+ T cells is avoided, as it may lead to systemic mouse graft-versus-host disease and acute allorejection of HEPs while transplanting with mismatched cells.
Commercially available hepatocytes were used as a source for liver reconstitution8,13. Adult hepatocytes are preferred for establishing liver reconstitution due to their increased efficiency in engraftment and sustainability for a long period of time29.
The presence of human immune system in a mouse model increased ALB levels, as shown previously30,31. However, the efficiency of hepatocytes and immune system reconstitution may vary with different sources of donor cells and depend on the recipient mouse. So, each mouse needs to be assessed for engraftment, and the most critical part is to utilize the antibodies or reagent that are human-specific and do not cross-react with mouse cells. The human-specific reagents and antibodies used in the study presented here are detailed in the Table of Materials. If antibodies other than provided in the Table of Materials are used for the study, be sure to check for the human specificity.
The optimal condition would be the transplantation of syngeneic cells; however, that is technically difficult to achieve. Wherever possible, HSPCs and hepatocytes should be pooled from donors with partially matched human leukocyte class-1 antigens (like HLA-A2).
To screen mice for HIV studies, blood is drawn at multiple time points to determine the optimal immune and liver reconstitution; flow cytometry and ELISA are preferred as they can be performed with only a little amount of blood. Blood cells and serum from the same sample could be used for flow cytometry and ELISA, respectively. It is important to make proper dilutions of serum at each time point (1,000 - 40,000 range) to evaluate ALB levels so that the unknown concentrations can be brought within the range of standard concentrations (kit range: 6.25 - 400 ng/mL).
Proinflammatory cytokines in response to HIV-1 infection in the presence of human immune system can also be useful in addressing the interaction of hepatocytes and immune cells. The model is useful for showing the immunopathogenesis of HIV-1-induced liver disease, given that it recapitulates liver damage in the same manner as in humans, evidenced by a low ratio of CD4:CD8, a decrease in ALB levels, human hepatocyte death, and liver immune activation. The model also has some limitations, such as a low level of cytotoxic T cells activity and impaired immunoglobulin class switching. Due to the presence of both human immune system and liver, the model presented here is promising for studi coinfections of HIV-1 and hepatitis viruses, chronic hepatitis infection (to clarify the mechanisms of the anti-hepatitis immune response), and as a cirrhosis model.

Since the advent of antiretroviral therapy, there has been a substantial decrease in deaths related to HIV-1 monoinfection. However, liver disease has emerged as a common cause of morbidity in HIV-infected patients1,2. Coinfections of hepatitis viruses with HIV-1 infection are more common, accounting for 10% - 30% of HIV-infected persons in the United States3,4,5.
The host-specificity of HIV-1 and hepatitis viruses limits the utility of small animal models to study human-specific infectious diseases or to investigate multiple aspects of HIV-1-associated liver pathogenesis. Immunodeficient mice that permit the engraftment of human cells and/or tissues (termed humanized mouse models) are acceptable animal models for preclinical studies6,7,8. Since the introduction of humanized mice in the early 2000s, multiple preclinical studies of cholestatic human liver toxicity, human-specific pathogens, including HIV-1 and HIV-associated neurocognitive disorders, Epstein Barr virus, hepatitis, and other infectious diseases, have been investigated in these mice6,9,10,11. Multiple mouse models for CD34+ HSPCs and/or human hepatocyte transplantation have long been developed and have improved over time to study the disease pathogenesis of Hepatitis B virus (HBV)-associated liver disease12,13,14. Several models for HSPC and human hepatocyte (HEP) transplantation are based on strains, known as NOG (NOD.Cg-Prkdcscid Il2rgtm1Sug/JicTac)8,13, NSG (NOD.Cg-Prkdcscid Il2rgtm1Wjl/SzJ)15, Balb/C-Rag2-/- &#947;c-/- (Rag2tm1.1Flv Il2rgtm1.1Flv/J)12, and fah-/- NOD rag1-/-il2r&#947;null mouse16. However, each model has its own advantages and limitations; for example, AFC8 dual humanized mice for HEPs and human stem cells (HSCs) on a Balb/C-Rag2-/- &#947;c-/-&#160;background enables the successful engraftment of immune cells and HSCs, but there is an absence of an antigen-specific T- and B-cell response in this model12. The major concerns in reconstituting double humanized mice include suboptimal engraftment, a lack of suitable models to support different tissues, mismatched conditions, immune rejection, or graft-versus-host disease (GVHD), and technical difficulties, such as risky manipulations with newborns and high mortality rates due to metabolic abnormalities13.
Although humanized mice have been used for HIV research for many years17,18,19, the use of humanized mice to study liver damage caused by HIV-1 has been limited20. We previously reported the establishment of a dual humanized TK-NOG mouse model and its application in HIV-associated liver disease8. This model shows the robust engraftment of liver and immune cells and recapitulates HIV infection pathogenesis. This discussion presents a detailed protocol, including the most critical steps in the transplantation of human hepatocytes. A description of the HSPCs required for a successful engraftment of HEPs and the establishment of a functional immune system in TK-NOG mice is also presented. The use of these mice to study HIV-associated liver immunopathogenesis is detailed. TK-NOG male mice carrying a liver-specific herpes simplex virus type 1 thymidine kinase (HSV-TK) transgene are used. Mouse liver cells expressing this transgene can easily be ablated after a brief exposure to a nontoxic dose of GCV. Transplanted human liver cells are stably maintained within the mouse liver without exogenous drugs21. The mice are also preconditioned with nonmyeloablative doses of treosulfan to create a niche in the mouse bone marrow for human cells8. Immunodeficient TK-NOG mice are intrasplenically injected with HEPs and multipotent HSPCs. The mice are then regularly monitored for blood and liver reconstitution by blood immunophenotyping and measurements of serum human-albumin levels, respectively. Mice with a successful reconstitution of more than 15% for both human immune cells and HEPs are intraperitoneally injected with HIV-1. The effect of HIV on the liver can be assessed as early as 4 - 5 weeks postinfection. It is critical to note that, because HIV-1 is used, all necessary precautions must be taken while handling the virus and injecting it into mice.

<table><tbody><tr><td>27 G1/2&quot; needles</td><td>BD biosciences</td><td>305109</td><td></td></tr><tr><td>30 G1/2&quot; needles</td><td>BD biosciences</td><td>305106</td><td></td></tr><tr><td>5 mL polystyrene&amp;nbsp; round-bottom tube 12 mm x 75 mm style</td><td>Corning</td><td>352054</td><td></td></tr><tr><td>BD 1 mL Tuberculin Syringe Without Needle</td><td>BD biosciences</td><td>309659</td><td></td></tr><tr><td>BD FACS array bioanalyzer&amp;nbsp;</td><td>BD Biosciences</td><td></td><td>For purity check of eluted CD34&lt;sup&gt;+&lt;/sup&gt; cells&amp;nbsp;</td></tr><tr><td>BD FACS array software</td><td>BD Biosciences</td><td></td><td>Software to analysis acquired CD34&lt;sup&gt;+&lt;/sup&gt; cell on FACS array</td></tr><tr><td>BD FACS lysing solution</td><td>BD Biosciences</td><td>349202</td><td>To lyse red blood cells</td></tr><tr><td>BD LSR II</td><td>BD Biosciences</td><td></td><td>Instrument for acquisiton of flow cytometry samples</td></tr><tr><td>BD&amp;nbsp;Vacutainer Plastic Blood Collection Tube</td><td>BD biosciences</td><td>BD 367874</td><td>To collect Cord blood</td></tr><tr><td>Bovine Serum Albumin&amp;nbsp;</td><td>Sigma-aldrich</td><td>A9576</td><td></td></tr><tr><td>Buprenorphine</td><td></td><td></td><td>Controlled substance and pain-killer</td></tr><tr><td>CD14-PE</td><td>BD Biosciences</td><td>555398</td><td>Specific to human</td></tr><tr><td>CD19-BV605</td><td>BD Biosciences</td><td>562653</td><td>Specific to human</td></tr><tr><td>CD34 MicroBead Kit, human</td><td>Miltenyi Biotec</td><td>130-046-702</td><td>For isoation of&amp;nbsp;&amp;nbsp; CD34&lt;sup&gt;+&lt;/sup&gt; HSPC</td></tr><tr><td>CD34-PE, human</td><td>Miltenyi Biotec</td><td>130-081-002</td><td>Antibody used for purity check of eluted CD34&lt;sup&gt;+&lt;/sup&gt; cells&amp;nbsp;</td></tr><tr><td>CD3-AF700</td><td>BD Biosciences</td><td>557943</td><td>Specific to human</td></tr><tr><td>CD45-PerCPCy5.5</td><td>BD Biosciences</td><td>564105</td><td>Specific to human</td></tr><tr><td>CD4-APC</td><td>BD Biosciences</td><td>555349</td><td>Specific to human</td></tr><tr><td>CD8-BV421</td><td>BD Biosciences</td><td>562428</td><td>Specific to human</td></tr><tr><td>Cell counting slides</td><td>Bio-rad</td><td>1450015</td><td></td></tr><tr><td>ChargeSwitch gDNA Mini Tissue Kit</td><td>Thermofisher scientific</td><td>CS11204</td><td>for extraction of genomic DNA from ear piece</td></tr><tr><td>Cobas Amplicor system v1.5&amp;nbsp;</td><td>Roche Molecular Diagnostics</td><td></td><td>bioanalyzer to measure viral load</td></tr><tr><td>Cotton-tipped applicators&amp;nbsp;</td><td>&amp;nbsp;McKesson</td><td>24-106-2S</td><td></td></tr><tr><td>Cytokeratin-18 (CK18)</td><td>DAKO</td><td>M7010</td><td>Specific to human</td></tr><tr><td>DMSO (Dimethyl sulfoxide)</td><td>Sigma-aldrich</td><td>D2650-5X5ML</td><td></td></tr><tr><td>Extension set Microbore Slide Clamp(s) Fixed Male Luer Lock. L: 60 in L: 152 cm PV: 0.55 mL Fluid Path Sterile</td><td>BD biosciences</td><td>30914</td><td>Attached to dispensing pippet and to load with HSPC and HEP suspesion</td></tr><tr><td>FACS Diva version 6</td><td>BD Biosciences</td><td></td><td>flow cytometer software required for&amp;nbsp; acqusition of sample</td></tr><tr><td>Fetal Bovine Serum (FBS)</td><td>Gibco</td><td>10438026</td><td></td></tr><tr><td>FLOWJO analysis software&lt;br/&gt; v10.2</td><td>FLOWJO, LLC</td><td></td><td>flow cytometry analysis software</td></tr><tr><td>Ganciclovir</td><td>APP Pharmaceuticals, Inc.</td><td>315110</td><td>Prescripition drug</td></tr><tr><td>Greiner MiniCollect EDTA Tubes</td><td>Greiner bio-one</td><td>450475</td><td></td></tr><tr><td>Hepatocytes thawing medium&amp;nbsp;</td><td>Triangle Research Labs&amp;nbsp;</td><td>MCHT50</td><td></td></tr><tr><td>Horizon Open Ligating Clip Appliers</td><td>Teleflex</td><td>537061</td><td>To hold the ligating clips</td></tr><tr><td>Hospira Sterile Water for Injection</td><td>ACE surgical supply co. Inc.</td><td>001-1187</td><td>For dilution of Buprenorphine (pain-killer)</td></tr><tr><td>Human Albumin ELISA Quantitation Set</td><td>Bethyl laboratories</td><td>E80-129</td><td>For assesing human albumin levels in mouse serum</td></tr><tr><td>Human hepatocyte</td><td>Triangle Research Labs&amp;nbsp;</td><td>HUCP1</td><td>&amp;nbsp;Cryopreserved human hepatocytes, induction qualified&amp;nbsp;</td></tr><tr><td>Iris Scissors, Straight</td><td>Ted Pella, Inc.</td><td>13295</td><td></td></tr><tr><td>Lancet</td><td>MEDIpoint</td><td>Goldenrod 5 mm</td><td></td></tr><tr><td>LS columns&amp;nbsp;</td><td>Miltenyi Biotec</td><td>130-042-401</td><td>Used to entrap CD34&lt;sup&gt;+&lt;/sup&gt; microbeads (positive selection)</td></tr><tr><td>Lymphocyte Separation Medium (LSM)</td><td>MP Biomedicals</td><td>50494</td><td>For isoation of&amp;nbsp;&amp;nbsp; lymphocytes from peripheral blood</td></tr><tr><td>MACS MultiStand</td><td>Miltenyi Biotec</td><td>130-042-303</td><td>holds Qudro MACS seperator and LS columns</td></tr><tr><td>McPherson-Vannas Micro Dissecting Spring Scissors</td><td>Roboz Surgical Instrument Co.</td><td>RS-5605</td><td>Used to make an incision on skin to expose spleen</td></tr><tr><td>Micro Dissecting Forceps</td><td>Roboz Surgical Instrument Co.</td><td>RS-5157&amp;nbsp;</td><td>to hold and pull out spleen from peritoneal cavity</td></tr><tr><td>mouse CD45-FITC</td><td>BD Biosciences</td><td>553080</td><td>mouse-specific</td></tr><tr><td>PBS (Phosphate Buffered Saline)</td><td>Hyclone</td><td>SH30256.02</td><td></td></tr><tr><td>Qudro MACS separator&amp;nbsp;</td><td>Miltenyi Biotec</td><td>130-090-976</td><td>holds four LS columns</td></tr><tr><td>RPMI 1640 medium</td><td>Gibco</td><td>11875093</td><td></td></tr><tr><td>StepOne Plus Real Time PCR&amp;nbsp;</td><td>Applied Biosystems</td><td></td><td>Instrument used&amp;nbsp; to&amp;nbsp; genotype</td></tr><tr><td>Stepper Series Repetitive Dispensing Pipette 1ml</td><td>DYMAX CORP</td><td>T15469</td><td>Used to&amp;nbsp; dispense&amp;nbsp; HSPC and HEP supension in controlled manner</td></tr><tr><td>Suturevet PGA synthetic absorbale suture</td><td>Henry Schein Animal Health</td><td>41178</td><td>Suturing of skin and peritoneum</td></tr><tr><td>TaqMan Gene Expression Master Mix</td><td>Thermofisher scientific</td><td>4369016</td><td></td></tr><tr><td>TC20 automated cell counter</td><td>Bio-rad</td><td>1450102</td><td></td></tr><tr><td>TK-NOG mice&amp;nbsp;</td><td></td><td></td><td>Provided by the Central Institute for Experimental Animals (CIEA, Japan; Drs. Mamoru Ito and Hiroshi Suemizu)</td></tr><tr><td>Treosulfan</td><td>Medac GmbH</td><td></td><td>Provided by &amp;nbsp;Dr. Joachim Baumgart (medac GmbH)&amp;nbsp;</td></tr><tr><td>Trypan Blue</td><td>Bio-rad</td><td>1450022</td><td></td></tr><tr><td>Vannas-type Micro Scissors, Straight, 80mm L</td><td>Ted Pella, Inc.</td><td>1346</td><td>Used to make an incision on skin to expose spleen</td></tr><tr><td>Weck hemoclip traditional titanium ligating clips</td><td>Esutures</td><td>523700</td><td>To ligate the spleen post-injection</td></tr></tbody></table>

establishment of the dual humanized tk-nog mouse model for hiv-associated liver pathogenesis

Despite the increased life expectancy of patients infected with human immunodeficiency virus-1 (HIV-1), liver disease has emerged as a common cause of their morbidity. The liver immunopathology caused by HIV-1 remains elusive. Small xenograft animal models with human hepatocytes and human immune system can recapitulate the human biology of the disease&#39;s pathogenesis. Herein, a protocol is described to establish a dual humanized mouse model through human hepatocytes and CD34+ hematopoietic stem/progenitor cells (HSPCs) transplantation, to study liver immunopathology as observed in HIV-infected patients. To achieve dual reconstitution, male TK-NOG (NOD.Cg-Prkdcscid Il2rgtm1Sug Tg(Alb-TK)7-2/ShiJic) mice are intraperitoneally injected with ganciclovir (GCV) doses to eliminate mouse transgenic liver cells, and with treosulfan for nonmyeloablative conditioning, both of which facilitate human hepatocyte (HEP) engraftment and human immune system (HIS) development. Human albumin (ALB) levels are evaluated for liver engraftment, and the presence of human immune cells in blood detected by flow cytometry confirms the establishment of human immune system. The model developed using the protocol described here resembles multiple components of liver damage from HIV-1 infection. Its establishment could prove to be essential for studies of hepatitis virus co-infection and for the evaluation of antiviral and antiretroviral drugs.

The establishment of a dual humanized mouse model with human liver and immune cells can be easily monitored at each step with very simple ELISA and flow cytometry, respectively. Flow cytometry is regularly performed to evaluate the development of a functional immune system and to see the effect of HIV infection on immune cells. In dual humanized mice, the development of functional immune cells can range from 15% to 90% of the lymphocyte gate. Representative subsets of immune cells are shown in dot plots (Figure 3). For the evaluation of the engraftment of human hepatocytes, ELISA for human-specific albumin levels is performed monthly on mouse serum. Mice engrafted with both HSPCs and HEPs show human-specific albumin levels ranging from ~7 &#181;g/mL to 377 &#181;g/mL at one month, continuing to grow over the time of observation (6 months) (Figure 4). The effect of HIV infection on human immune cells in the blood of dual humanized mice is monitored by flow cytometry and on HEPs in the liver by human-specific albumin ELISA. By 5 weeks, HIV-1 causes a decrease in human albumin levels in the serum, as assessed by ELISA, and there is a depletion of human CK18+ hepatocytes in the liver sections of dual humanized mice, as evaluated by immunohistochemistry (Figure 5). A lower ratio of CD4:CD8 is typically observed, by flow cytometry, in the blood and liver of HIV-infected mice, compared to levels noted in the same mouse before infection (Figure 6). All reagents and materials important for the protocol are discussed in the Table of Materials.
<img alt="Figure 1" class="xfigimg" src="/files/ftp_upload/58645/58645fig1.jpg" /> 
Figure 1: Schematic of the enrichment of CD34+ cells from cord blood. (A) Cord blood is layered on lymphocytes separation medium (LSM) and centrifuged to isolate buffy coat. (B) LS columns are placed on a magnetic stand and rinsed with BSA buffer, followed by adding buffy coat. Cells positive for CD34 are trapped in the columns, and CD34- cells are eluted in separate tubes. Trapped CD34+ cells in column resins are plunged with a plunger, and the cells are collected in a new tube. <a href="https://www-jove-com.remotexs.ntu.edu.sg/files/ftp_upload/58645/58645fig1large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>
<img alt="Figure 2" class="xfigimg" src="/files/ftp_upload/58645/58645fig2v2.jpg" /> 
Figure 2: Schematic view of the experimental design for the dual reconstitution of humanized liver and immune system mice, followed by HIV-1 infection. TK-NOG mice are injected with ganciclovir (GCV) at a dose of 6 mg/kg, 2x a day, on day -7 and day -5, followed by a treosulfan injection on days -3, -2 and -1. To screen the mice for the transplantation (Tx), an alanine aminotransferase (ALT) assay is performed one day before the surgery, and mice with ALT levels of &#62;200 and &#60;600 U/L are selected. After transplantation, the mice are checked for a reconstitution of the human immune system by flow cytometry (FACS) and for liver reconstitution by assessing their albumin level using ELISA. The mice are infected with HIV-1 5 weeks before they are sacrificed. <a href="https://www-jove-com.remotexs.ntu.edu.sg/files/ftp_upload/58645/58645fig2large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>
<img alt="Figure 3" class="xfigimg" src="/files/ftp_upload/58645/58645fig3v2.jpg" /> 
Figure 3:&#160;Flow cytometry analysis gating strategy for the human cell distribution of blood. (A) First, lymphocytes are gated on whole blood based on FSC-A and SSC-A. (B) Single cells are gated on lymphocytes. (C) Human CD45+ leukocytes are gated on single cells using mouse CD45 and human CD45. (D) CD3+ T cells and CD19+ B cells are identified on gated CD45+ human leukocytes. (E) CD4+ T helper cells and CD8+ cytotoxic T cells are identified in gated CD3+ T cells. (F) CD14+ monocytes are gated from human CD45+ leukocytes. The results represented here are from one mouse transplanted with dual human hepatocytes and HSPCs. <a href="https://www-jove-com.remotexs.ntu.edu.sg/files/ftp_upload/58645/58645fig3large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>
<img alt="Figure 4" class="xfigimg" src="/files/ftp_upload/58645/58645fig4.jpg" /> 
Figure 4: Albumin concentration is measured by ELISA in the serum of dual humanized mice. The mice are transplanted with both human hepatocytes (HEPs) and CD34+ hematopoietic stem/progenitor cells (HSPCs) (n = 11). Serum is collected at different times at 1, 4, and 6 months posttransplantation, and dilutions are made to adjust the unknown sample concentrations in the range of standards. Each symbol represents an individual mouse value. The results represent the median, as well as individual values. * P &#60; 0.05, by one-way ANOVA. This figure has been modified from Dagur et al.8. <a href="https://www-jove-com.remotexs.ntu.edu.sg/files/ftp_upload/58645/58645fig4large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>
<img alt="Figure 5" class="xfigimg" src="/files/ftp_upload/58645/58645fig5v2.jpg" /> 
Figure 5: Effect on HIV-1 on albumin levels in serum and the depletion of CK18+ human hepatocytes in the liver of dual humanized mice. (A) Albumin concentrations are monitored in uninfected mice (n = 9) transplanted with both human HEPs and HSPCs at 1 and 4 months. The mice are infected (n = 10) with HIV at 4 - 5 months posttransplantation and sacrificed 5 weeks postinfection. Each symbol represents an individual mouse value. The results represent the median, as well as individual values. * P &#60; 0.05, by one-way ANOVA. This figure has been modified from Dagur et al.8. (B) Five-micron liver sections from uninfected (HEPs + HSPCs, left panel) and HIV-infected TK-NOG mice (HEPs + HSPCs + HIV, right panel) are fixed, paraffin embedded, and stained for anti-human cytokeratin-18 (CK18) antibody. HIV-1 causing a depletion of CK18+ hepatocytes is evidenced by a less occupied area by the CK18+ human cells. The results represented here are from one uninfected and one HIV-infected mouse transplanted with dual human hepatocytes and HSPCs. Scale bars = 100 &#181;m. <a href="https://www-jove-com.remotexs.ntu.edu.sg/files/ftp_upload/58645/58645fig5large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>
<img alt="Figure 6" class="xfigimg" src="/files/ftp_upload/58645/58645fig6v2.jpg" /> 
Figure 6: Ratio of CD4+ cells to CD8+ T cells in peripheral blood and in the liver of dual reconstituted uninfected and HIV-1-infected mice. For dual reconstituted uninfected mice: closed circle; HEPs + HSPCs; blood n = 7; liver n = 6. For HIV-1 infected mice: open circles; HEPs + HSPCs + HIV; blood n = 10; liver n = 11. The results represent the median, as well as individual values. * P &#60; 0.05, by one-way ANOVA test between HIV-infected and uninfected mice. This figure has been modified from Dagur et al.8. <a href="https://www-jove-com.remotexs.ntu.edu.sg/files/ftp_upload/58645/58645fig6large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>

Watch this Scientific Journal Video about Establishment of the Dual Humanized TK-NOG Mouse Model for HIV-associated Liver Pathogenesis at JoVE.com

Establishment of the Dual Humanized TK-NOG Mouse Model for HIV-associated Liver Pathogenesis

This protocol provides a reliable method to establish humanized mice with both human immune system and liver cells. Dual reconstituted immunodeficient mice achieved via intrasplenic injection of human hepatocytes and CD34+ hematopoietic stem cells are susceptible to human immunodeficiency virus-1 infection and recapitulate liver damage as observed in HIV-infected patients.

Despite the increased life expectancy of patients infected with human immunodeficiency virus-1 (HIV-1), liver disease has emerged as a common cause of ...

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Nanyang Technological University

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JoVE Journal

Immunology and Infection

8.5K Views.  University of Nebraska Medical Center. Het algemene doel van het protocol is het genereren van een gehumaniseerd muismodel met functioneel menselijk immuunsysteem en lever met behulp van menselijke hematopoietische stamcellen en hepato-site. Deze methode kan helpen bij het beantwoorden van belangrijke vragen in genetische lever gehumaniseerde muizen. Deze methode biedt een krachtig hulpmiddel om immunopathologie veroorzaakt door HIV te bestuderen, zoals waargenomen bij mensen.Het aantonen van het proces zal worden door Yimi...

Video: Establishment of the Dual Humanized TK-NOG Mouse Model for HIV-associated Liver Pathogenesis

In vitro Biofilm Formation in an 8-well Chamber Slide

The chronic nature of many diseases is attributed to the formation of bacterial biofilms which are recalcitrant to traditional antibiotic therapy. Biofilms are community-associated bacteria attached to a surface and encased in a matrix. The role of the extracellular matrix is multifaceted, including facilitating nutrient acquisition, and offers significant protection against environmental stresses (e.g. host immune responses). In an effort to acquire a better understanding as to how the bacteria within a biofilm respond to environmental stresses we have used a protocol wherein we visualize bacterial biofilms which have formed in an 8-well chamber slide. The biofilms were stained with the BacLight Live/Dead stain and examined using a confocal microscope to characterize the relative biofilm size, and structure under varying incubation conditions. Z-stack images were collected via confocal microscopy and analyzed by COMSTAT. This protocol can be used to help elucidate the mechanism and kinetics by which biofilms form, as well as identify components that are important to biofilm structure and stability.

In vitro Biofilm Formation in an 8-well Chamber Slide

This article describes the procedure for the formation and visualization of a bacterial biofilm grown within an 8-well chamber slide

The chronic nature of many diseases is attributed to the formation of bacterial biofilms which are recalcitrant to traditional antibiotic therapy. ...

Using the BLT Humanized Mouse as a Stem Cell based Gene Therapy Tumor Model

Small animal models such as mice have been extensively used to study human disease and to develop new therapeutic interventions. Despite the wealth of information gained from these studies, the unique characteristics of mouse immunity as well as the species specificity of viral diseases such as human immunodeficiency virus (HIV) infection led to the development of humanized mouse models. The earlier models involved the use of C. B 17 scid/scid mice and the transplantation of human fetal thymus and fetal liver termed thy/liv (SCID-hu) 1, 2 or the adoptive transfer of human peripheral blood leukocytes (SCID-huPBL) 3. Both models were mainly utilized for the study of HIV infection.
One of the main limitations of both of these models was the lack of stable reconstitution of human immune cells in the periphery to make them a more physiologically relevant model to study HIV disease. To this end, the BLT humanized mouse model was developed. BLT stands for bone marrow/liver/thymus. In this model, 6 to 8 week old NOD.Cg-Prkdcscid Il2rgtm1Wjl/SzJ (NSG) immunocompromised mice receive the thy/liv implant as in the SCID-hu mouse model only to be followed by a second human hematopoietic stem cell transplant 4. The advantage of this system is the full reconstitution of the human immune system in the periphery. This model has been used to study HIV infection and latency 5-8.
We have generated a modified version of this model in which we use genetically modified human hematopoietic stem cells (hHSC) to construct the thy/liv implant followed by injection of transduced autologous hHSC 7, 9. This approach results in the generation of genetically modified lineages. More importantly, we adapted this system to examine the potential of generating functional cytotoxic T cells (CTL) expressing a melanoma specific T cell receptor. Using this model we were able to assess the functionality of our transgenic CTL utilizing live positron emission tomography (PET) imaging to determine tumor regression (9).
The goal of this protocol is to describe the process of generating these transgenic mice and assessing in vivo efficacy using live PET imaging. As a note, since we use human tissues and lentiviral vectors, our facilities conform to CDC NIH guidelines for Biosafety Level 2 (BSL2) with special precautions (BSL2+). In addition, the NSG mice are severely immunocompromised thus, their housing and maintenance must conform to the highest health standards (<a href="http://jaxmice.jax.org/research/immunology/005557-housing.html" target="_blank">http://jaxmice.jax.org/research/immunology/005557-housing.html</a>).

The generation and characterization of tumor specific T cells using humanized mice is described here. Human thymic tissue and genetically modified human hematopoietic stem cells are transplanted into immunocompromised mice. This results in the reconstitution of an engineered human immune system allowing for in vivo examination of anti-tumor immune responses.

Small animal models such as mice have been extensively used to study human  disease and to develop new therapeutic interventions. Despite the wealth of  ...

Stem-cell Based Engineered Immunity Against HIV Infection in the Humanized Mouse Model

With the rapid development of stem cell-based gene therapies against HIV, there is pressing requirement for an animal model to study the hematopoietic differentiation and immune function of the genetically modified cells. The humanized Bone-marrow/Liver/Thymus (BLT) mouse model allows for full reconstitution of a human immune system in the periphery, which includes T cells, B cells, NK cells and monocytes. The human thymic implant also allows for thymic selection of T cells in autologous thymic tissue. In addition to the study of HIV infection, the model stands as a powerful tool to study differentiation, development and functionality of cells derived from hematopoietic stem cells (HSCs). Here we outline the construction of humanized non-obese diabetic (NOD)-severe combined immunodeficient (SCID)-common gamma chain knockout (c&#947;-/-)-Bone-marrow/Liver/Thymus (NSG-BLT) mice with HSCs transduced with CD4 chimeric antigen receptor (CD4CAR) lentivirus vector. We show that the CD4CAR HSCs can successfully differentiate into multiple lineages and have anti-HIV activity. The goal of the study is to demonstrate the use of NSG-BLT mouse model as an in vivo model for engineered immunity against HIV. It is worth noting that, because lentivirus and human tissue is used, experiments and surgeries should be performed in a Class II biosafety cabinet in a Biosafety Level 2 (BSL2) with special precautions (BSL2+) facility.

This protocol describes the methods in constructing a humanized bone-marrow/liver/thymus mouse model with stem cell-based engineered immunity against HIV infection.

With the rapid development of stem cell-based gene therapies against HIV, there is pressing requirement for an animal model to study the hematopoietic ...

Medicine

Humanized NOD/SCID/IL2r&#947;null (hu-NSG) Mouse Model for HIV Replication and Latency Studies

Ethical regulations and technical challenges for research in human pathology, immunology, and therapeutic development have placed small animal models in high demand. With a close genetic and behavioral resemblance to humans, small animals such as the mouse are good candidates for human disease models, through which human-like symptoms and responses can be recapitulated. Further, the mouse genetic background can be altered to accommodate diverse demands. The NOD/SCID/IL2r&#947;null (NSG) mouse is one of the most widely used immunocompromised mouse strains; it allows engraftment with human hematopoietic stem cells and/or human tissues and the subsequent development of a functional human immune system. This is a critical milestone in understanding the prognosis and pathophysiology of human-specific diseases such as HIV/AIDS and aiding the search for a cure. Herein, we report a detailed protocol for generating a humanized NSG mouse model (hu-NSG) by hematopoietic stem cell transplantation into a radiation-conditioned neonatal NSG mouse. The hu-NSG mouse model shows multi-lineage development of transplanted human stem cells and susceptibility to HIV-1 viral infection. It also recapitulates key biological characteristics in response to combinatorial antiretroviral therapy (cART).

This protocol provides a method to establish humanized mice (hu-NSG) via intrahepatic injection of human hematopoietic stem cells into radiation-conditioned neonatal NSG mice. The hu-NSG mouse is susceptible to HIV infection and combinatorial antiretroviral therapy (cART) and serves as a suitable pathophysiological model for HIV replication and latency investigations.

Ethical regulations and technical challenges for research in human pathology, immunology, and therapeutic development have placed small animal models in ...

Chronic, Acute, and Reactivated HIV Infection in Humanized Immunodeficient Mouse Models

Humanized NOD/SCID/IL-2 receptor &#947;-chainnull mice recapitulate some features of human immunity, which can be exploited in basic and pre-clinical research on infectious diseases. Described here are three models of humanized immunodeficient mice for studying the dynamics of HIV infection. The first is based on the intrahepatic injection of CD34+ hematopoietic stem cells in newborn mice, which allows for the reconstitution of several blood and lymphoid tissue-confined cells, followed by infection with a reference HIV strain. This model allows monitoring for up to 36 weeks post-infection and is hence called the chronic model. The second and third models are referred to as the acute and reactivation models, in which peripheral blood mononuclear cells are intraperitoneally injected in adult mice. In the acute model, cells from a healthy donor are engrafted through the intraperitoneal route, followed by infection with a reference HIV strain. Finally, in the reactivation model, cells from an HIV-infected donor under antiretroviral therapy are engrafted via the intraperitoneal route. In this case, a drug-free environment in the mouse allows for virus reactivation and an increase in viral load. The protocols provided here describe the conventional experimental approach for humanized, immunodeficient mouse models of HIV infection.

Described here are three experimental approaches for studying the dynamics of HIV infection in humanized mice. The first permits the study of chronic infection events, whereas the two latter allows for the study of acute events after primary infection or viral reactivation.

Humanized NOD/SCID/IL-2 receptor &#947;-chainnull mice recapitulate some features of human immunity, which can be exploited in basic and pre-clinical ...

Humanized NOG Mice for Intravaginal HIV Exposure and Treatment of HIV Infection

Humanized mice provide a sophisticated platform to study human immunodeficiency virus (HIV) virology and to test antiviral drugs. This protocol describes the establishment of a human immune system in adult NOG mice. Here, we explain all the practical steps from isolation of umbilical cord blood derived human CD34+ cells and their subsequent intravenous transplantation into the mice, to the manipulation of the model through HIV infection, combination antiretroviral therapy (cART), and blood sampling. Approximately 75,000 hCD34+ cells are injected intravenously into the mice and the level of human chimerism, also known as humanization, in the peripheral blood is estimated longitudinally for months by flow cytometry. A total of 75,000 hCD34+ cells yields 20%&#8211;50% human CD45+ cells in the peripheral blood. The mice are susceptible to intravaginal infection with HIV and blood can be sampled once weekly for analysis, and twice monthly for extended periods. This protocol describes an assay for quantification of plasma viral load using droplet digital PCR (ddPCR). We show how the mice can be effectively treated with a standard-of-care cART regimen in the diet. The delivery of cART in the form of regular mouse chow is a significant refinement of the experimental model. This model can be used for preclinical analysis of both systemic and topical pre-exposure prophylaxis compounds as well as for testing of novel treatments and HIV cure strategies.

We have developed a protocol for the generation and evaluation of a humanized and human immunodeficiency virus-infected NOG mouse model based on stem cell transplant, intravaginal human immunodeficiency virus exposure, and droplet digital PCR RNA quantification.

Humanized mice provide a sophisticated platform to study human immunodeficiency virus (HIV) virology and to test antiviral drugs. This protocol describes ...

Oral Combinational Antiretroviral Treatment in HIV-1 Infected Humanized Mice

The human immunodeficiency virus (HIV-1) pandemic continues to spread unabated worldwide, and currently, there is no vaccine available against HIV. Although combinational antiretroviral therapy (cART) has been successful in suppressing viral replication, it cannot completely eradicate the reservoir from HIV-infected individuals. A safe and effective cure strategy for HIV infection will require multipronged methods, and therefore the advancements of animal models for HIV-1 infection are pivotal for the development of HIV cure research. Humanized mice recapitulate key features of HIV-1 infection. The humanized mouse model can be infected by HIV-1 and viral replication can be controlled with cART regimens. Moreover, cART interruption results in a prompt viral rebound in humanized mice. However, administration of cART to the animal can be ineffective, difficult, or toxic, and many clinically relevant cART regimens are unable to be optimally utilized. Along with being potentially unsafe for researchers, administration of cART by a commonly used intensive daily injection procedure induces stress by physical restraint of the animal. The novel oral cART method to treat HIV-1 infected humanized mice described in this article resulted in suppression of viremia below the detection level, increased rate of CD4+ restoration, and improved overall health in HIV-1 infected humanized mice.

This protocol describes a novel method to deliver oral combinational antiretroviral drugs that successfully suppress HIV-1 RNA replication in humanized mice.

The human immunodeficiency virus (HIV-1) pandemic continues to spread unabated worldwide, and currently, there is no vaccine available against HIV. ...

Oral Combinational Antiretroviral Therapy to Treat HIV-1 Infection in a Humanized Mouse Model

Source: Mu, W., et al. <a href="https://app-jove-com.remotexs.ntu.edu.sg/v/63696">Oral Combinational Antiretroviral Treatment in HIV-1 Infected Humanized Mice.</a> J. Vis. Exp. (2022).
This video demonstrates an assay to evaluate the effectiveness of oral combined antiretroviral therapy (oral cART) in a human immunodeficiency virus-1 (HIV-1)-infected humanized mouse model. A combination of drugs targeting HIV-1, including nucleoside reverse transcriptase inhibitors and integrase strand transfer inhibitors, is administered along with a nutritional supplement and antibiotics. Following the consumption of this mixture by the humanized mice infected with HIV-1, the effective suppression of viral replication is assessed through periodic examinations of the mice.

All procedures involving animal models have been reviewed by the local institutional animal care committee and the JoVE veterinary review board.
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Immunology

Immunotherapy

Model Development and Disease Study

Developing a Humanized Mouse Model with Human Liver Cells and Immune Cells

Source: Dagur, R. S. et al., <a href="https://app-jove-com.remotexs.ntu.edu.sg/v/58645">Establishment of the Dual Humanized TK-NOG Mouse Model for HIV-associated Liver Pathogenesis.</a>&#160;J. Vis. Exp.&#160;(2019)
This video demonstrates a method for generating a dual humanized mouse model with a human immune system and liver cells. It involves transplanting human liver cells and hematopoietic stem and progenitor cells into a transgenic immunodeficient mouse via intrasplenic injection, leading to engraftment of liver cells and development of human immune cells.

Constructing a Humanized Mouse Model with Engineered Immunity against HIV

Source: Zhen, A., et al. <a href="https://app-jove-com.remotexs.ntu.edu.sg/v/54048">Stem-cell Based Engineered Immunity Against HIV Infection in the Humanized Mouse Model.</a> J. Vis. Exp. (2016).
The video demonstrates a technique to generate a humanized mouse model with stem-cell-based engineered immunity against the human immunodeficiency virus (HIV). Human fetal thymus tissue and engineered hematopoietic stem cells (HSCs) are implanted into the kidney capsule of a severely immunocompromised mouse. The HSCs, which express chimeric antigen receptors (CARs) against HIV, are mixed in a gelatinous protein mixture that promotes their co-localization with thymus tissue. Post-procedure, the HSCs differentiate into various human immune cells, resulting in the development of a humanized mouse model with a functional human immune system against HIV.

All procedures involving sample collection have been performed in accordance with the institute&#39;s IRB guidelines. All procedures involving animal ...

Establishment of the Dual Humanized TK-NOG Mouse Model for HIV-associated Liver Pathogenesis

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