This work was funded by NIH grant R01AI077610.

All procedures were conducted in accordance with the Guide for the Care and Use of Laboratory Animals of the National Institute of Health (NIH) and were approved by the Johns Hopkins University Animal Care and Use Committee (JHUACUC). The specific procedures were performed under the approved ACUC protocols MO13M292 and MO13M370.
1. Donor Skin Harvest
<ol>
	<li>Anesthetize the donor mouse with isoflurane (induction vaporizer at 4%, maintenance at 1 - 2% through the mouse cone). Use the toe pinch withdrawal reflex to monitor the depth of anesthesia.</li>
	<li>Using an electric razor, shave the back of the animal and disinfect it with 10% povidone iodine (e.g., Betadine).</li>
	<li>Using sterile scissors, gloves, and aseptic technique, harvest donor back skin from the hip to the neck, with blunt dissection at the level of the areolar connective tissue.</li>
	<li>Euthanize the animal by cervical dislocation after harvesting the skin graft.</li>
	<li>Under a microscope, separate the connective tissue, fat tissue, and panniculus carnosus from the back skin using fine tenotomy scissors. The panniculus carnosus is a thin, transparent muscle responsible for skin twitching movements.</li>
	<li>Using sterile instruments technique, cut out 15-mm x 15-mm grafts from the back skin for a 10-mm x 10-mm to 15-mm x 15-mm graft bed.</li>
	<li>Store the grafts on gauzes soaked with sterile phosphate-buffered saline (PBS) in a petri dish on ice. 
	NOTE: 8 - 10 grafts can be obtained from one donor mouse.</li>
</ol>
2. Recipient Skin Transplant
<ol>
	<li>Anesthetize the recipient mouse with isoflurane (induction vaporizer at 4%, maintenance at 1 - 2% through the mouse cone). Use the toe pinch withdrawal reflex to monitor the depth of anesthesia.</li>
	<li>Administer 0.02 mg/kg BW of Buprenorphine for postoperative pain relief.</li>
	<li>Shave the side of the back of the animal where the graft will be inserted and disinfect with 10% povidone iodine.</li>
	<li>Using scissors, cut a 10-mm x 10-mm to 15-mm x 15-mm square of skin. The defect size should be slightly larger (10%) than the graft. Cut as superficially as possible. Take care to preserve the panniculus carnosus and vessels. The panniculus carnosus can be distinguished from the underlying fascia by its mobility and the blood vessels that run superficial to it.</li>
	<li>Position the graft on the graft bed, avoiding folds along the edges.</li>
	<li>Place 8 sutures on the corners and on the middle of each edge. For each suture, pass the needle through the graft and then through the panniculus carnosus of the graft bed below the surrounding recipient skin.</li>
	<li>Remove the anesthetic mask and let the animal recover partially from anesthesia before applying the adhesive bandage.</li>
	<li>Wrap the recipient mouse in an adhesive bandage with folded gauze over the graft. Make the bandage by combining two bandages, cutting the adhesive part of one and placing the two absorbent pads together.</li>
	<li>Monitor the mouse closely during recovery to ensure that the bandage is not restricting thorax excursion and breathing. Remove the bandage if the respiratory rate decreases or the animal starts to gasp or breath shallowly.</li>
</ol>
3. Postoperative Care
<ol>
	<li>Administer enrofloxacin 5 mg/kg after surgery for infection prophylaxis.</li>
	<li>Place the transplanted mouse in a clean cage over a microwavable heating pad&#160;until it fully recovers from anesthesia.</li>
	<li>Observe the mouse for 1 hr postoperatively prior to returning it to the housing facility.</li>
	<li>Seven days after surgery, anesthetize the mouse as in Step 2.1. Remove the bandage by cutting only through the ventral side of the bandage.</li>
	<li>Observe and palpate the graft on the following day for signs of scabbing, contraction, or hardness. If present, the graft may not have achieved proper vascularization and should be considered a technical failure.</li>
	<li>Monitor daily for signs of rejection. Consider grafts rejected when &#8805;90% of the graft tissue becomes necrotic.</li>
	<li>Euthanize the rejected animals and harvest them for analysis.</li>
</ol>

<ol>
	<li>Furtmuller, G. J., 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=Orthotopic+Hind+Limb+Transplantation+in+the+Mouse.">Orthotopic Hind Limb Transplantation in the Mouse.</a> J Vis Exp. , (2016).</li><li>Oh, B., 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=A+Novel+Microsurgical+Model+for+Heterotopic,+En+Bloc+Chest+Wall,+Thymus,+and+Heart+Transplantation+in+Mice.">A Novel Microsurgical Model for Heterotopic, En Bloc Chest Wall, Thymus, and Heart Transplantation in Mice.</a> J Vis Exp. , (2016).</li><li>Oberhuber, R., 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=Murine+cervical+heart+transplantation+model+using+a+modified+cuff+technique.">Murine cervical heart transplantation model using a modified cuff technique.</a> J Vis Exp. , e50753 (2014).</li><li>Jones, T. R., Shirasugi, N., Adams, A. B., Pearson, T. C., Larsen, C. P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Intravital+microscopy+identifies+selectins+that+regulate+T+cell+traffic+into+allografts.">Intravital microscopy identifies selectins that regulate T cell traffic into allografts.</a> J Clin Invest. 112, 1714-1723 (2003).</li><li>Celli, S., Albert, M. L., Bousso, P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Visualizing+the+innate+and+adaptive+immune+responses+underlying+allograft+rejection+by+two-photon+microscopy.">Visualizing the innate and adaptive immune responses underlying allograft rejection by two-photon microscopy.</a> Nat Med. 17, 744-749 (2011).</li><li>Medawar, P. B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+behaviour+and+fate+of+skin+autografts+and+skin+homografts+in+rabbits:+A+report+to+the+War+Wounds+Committee+of+the+Medical+Research+Council.">The behaviour and fate of skin autografts and skin homografts in rabbits: A report to the War Wounds Committee of the Medical Research Council.</a> J Anat. 78, 176-199 (1944).</li><li>Billingham, R. E., Brent, L., Medawar, P. B., Sparrow, E. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Quantitative+studies+on+tissue+transplantation+immunity.+I.+The+survival+times+of+skin+homografts+exchanged+between+members+of+different+inbred+strains+of+mice.">Quantitative studies on tissue transplantation immunity. I. The survival times of skin homografts exchanged between members of different inbred strains of mice.</a> Proc R Soc Lond B Biol Sci. 143, 43-58 (1954).</li><li>Garrod, K. R., Cahalan, M. D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Murine+skin+transplantation.">Murine skin transplantation.</a> J Vis Exp. , (2008).</li><li>Schmaler, M., Broggi, M. A., Rossi, S. W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Transplantation+of+tail+skin+to+study+allogeneic+CD4+T+cell+responses+in+mice.">Transplantation of tail skin to study allogeneic CD4 T cell responses in mice.</a> J Vis Exp. , e51724 (2014).</li><li>Bergstresser, P. R., Toews, G. B., Gilliam, J. N., Streilein, J. W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Unusual+numbers+and+distribution+of+Langerhans+cells+in+skin+with+unique+immunologic+properties.">Unusual numbers and distribution of Langerhans cells in skin with unique immunologic properties.</a> J Invest Dermatol. 74, 312-314 (1980).</li><li>Chen, H. D., Silvers, W. K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Influence+of+Langerhans+cells+on+the+survival+of+H-Y+incompatible+skin+grafts+in+rats.">Influence of Langerhans cells on the survival of H-Y incompatible skin grafts in rats.</a> J Invest Dermatol. 81, 20-23 (1983).</li><li>Chong, A. S., Alegre, M. L., Miller, M. L., Fairchild, R. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Lessons+and+limits+of+mouse+models.">Lessons and limits of mouse models.</a> Cold Spring Harb Perspect Med. 3, a015495 (2013).</li><li>Mayumi, H., Nomoto, K., Good, R. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+surgical+technique+for+experimental+free+skin+grafting+in+mice.">A surgical technique for experimental free skin grafting in mice.</a> Jpn J Surg. 18, 548-557 (1988).</li><li>McFarland, H. I., Rosenberg, A. S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Skin+allograft+rejection.">Skin allograft rejection.</a> Curr Protoc Immunol. Chapter 4, (2009).</li><li>Lee, C. F., 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=Preventing+Allograft+Rejection+by+Targeting+Immune+Metabolism.">Preventing Allograft Rejection by Targeting Immune Metabolism.</a> Cell reports. 13, 760-770 (2015).</li><li>Pollizzi, K. N., Powell, J. D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Integrating+canonical+and+metabolic+signalling+programmes+in+the+regulation+of+T+cell+responses.">Integrating canonical and metabolic signalling programmes in the regulation of T cell responses.</a> Nat Rev Immunol. 14, 435-446 (2014).</li><li>Pearce, E. L., Poffenberger, M. C., Chang, C. H., Jones, R. G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Fueling+immunity:+insights+into+metabolism+and+lymphocyte+function.">Fueling immunity: insights into metabolism and lymphocyte function.</a> Science. 342, 1242454 (2013).</li></ol>

The authors have nothing to disclose.

Since its introduction by Medawar, first in human studies and then in rabbits and mice, skin transplantation has been an invaluable model for the study of allogeneic immune responses6,7. In this manuscript, we present a model of large-scale, non-vascularized, full-thickness skin transplantation using the upper and lower back skin. Various alternative methods, including using the tail skin or ear skin of the mouse as the graft tissue source, have been reported to date8,9. These models present the distinct advantage of technical simplicity and allow for high-volume throughput. The relative deficiency of epidermal Langerhans cells and dermal dendritic cells in tail skin grafts, however, leads to delayed rejection as well as to facilitated graft acceptance by the host, particularly in minor MHC mismatch models10,11. Therefore, full-thickness trunk skin grafting is considered a more robust model and more suitable to study T-cell-mediated acute rejection12.
In addition, our model employs simple techniques and does not require advanced microsurgical skills. The operating time is short (~ 10 min per mouse from the onset of anesthesia to the completion of the procedure), and the postoperative morbidity and mortality is negligible. The overall operative mortality (death within 24 hr after surgery plus death before removal of the bandage) has been reported to be 3.8%13. Most of the complications arise from anesthesia overdose or overly-restrictive bandages, which can be easily prevented by close monitoring of respiratory function during the immediate postoperative period and by rapid removal of the bandage at the earliest signs of respiratory distress6,17.
The most critical factor in the process of engraftment is the revascularization of graft tissue by the ingrowth of host vessels to the graft6. The harvested skin requires careful preparation, and the dissection of the panniculus carnosus is a critical step. We prefer to remove the panniculus carnosus under a microscope. It is recommended to start the dissection from one of the edges and to advance slowly by pushing the muscle and separating it from the skin with the blade of a curved tenotomy angled slightly. The site of the graft bed should be far from joints and the spine. Before making incisions into the recipient mouse, the shoulder and hip should be moved to visualize the skin folds that help to demarcate the level of the joints. When removing the recipient skin, it is important to avoid damaging the blood vessels that run superficial to the panniculus carnosus. If bleeding occurs, apply local compression and remove blood and clots that may interfere with engraftment. Finally, the bandage should not cause breathing difficulties that compromise recovery, although it must be sufficiently constrictive to prevent displacement of the graft and auto-mutilation during the process of revascularization. Plastic Strips Band-Aids are adherent and strong enough for this purpose. We combine two bandages to completely wrap the mouse waist and to allow the placement of a folded gauze between the bandage and the graft (Figure 1). The bandage is removed by cutting the ventral side of it, and the rest is removed by the animal, in order to avoid disrupting the graft while trying to remove the bandage manually.
In summary, full-thickness skin transplantation is a well-established model with abundant references in the literature. The procedure is easy to perform, the operating time is short, and the postoperative complications are limited. The critical steps are related to meticulous donor skin harvest and the correct placement of the recipient bandage. Future studies involving biomaterials that promote angiogenesis and tissue repair may further improve the success rate of the procedure.

Organ transplantation is the treatment of choice for patients with end-stage organ failure, and outcomes have improved remarkably with advances in surgical procedures and immunosuppression protocols. However, long-term immunosuppression is associated with significant side effects, and the development of new strategies that promote tolerance remains the goal of modern transplantation research.
Numerous animal models have been developed for basic research in transplantation, to study the mechanisms of allograft rejection and to test immunosuppression approaches for preventing graft rejection and for promoting long-term tolerance1-3. Mouse models have become the mainstay of immunological research due to the exclusive and vast availability of diagnostic and therapeutic antibodies and well-defined inbred and transgenic strains. Skin transplantation is a simple procedure that does not require special microsurgical skills and can be easily monitored postoperatively. Taken together, mouse skin transplantation has been an exceptional tool to study many aspects involved in the alloimmune response, including antigen delivery, cell trafficking, and tissue destruction during graft rejection4,5.
Here, we show the step-by-step procedure for full-thickness skin transplantation using the mouse model, and we describe the important steps necessary for a successful engraftment of the transplanted skin.

<table border="0" cellpadding="0" cellspacing="0" width="923">
	<tbody>
		<tr height="21">
			<td height="21" style="height:21px;width:247px;">Straight micro forceps&#160;</td>
			<td style="width:125px;">Sigma</td>
			<td style="width:136px;">F4017</td>
			<td style="width:415px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:247px;">Curved micro forceps&#160;</td>
			<td style="width:125px;">Aesculap</td>
			<td style="width:136px;">BD333R</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:247px;">Curved Stevens tenotomy scissors&#160;</td>
			<td style="width:125px;">Aesculap</td>
			<td style="width:136px;">BC905R</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:247px;">Mayo dissecting&#160; scissors</td>
			<td style="width:125px;">Sigma</td>
			<td style="width:136px;">S3146</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:247px;">Micro needle holder</td>
			<td style="width:125px;">Aesculap</td>
			<td style="width:136px;">BM563R</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:247px;">Sterile gauze</td>
			<td style="width:125px;">Covidien</td>
			<td style="width:136px;">441218</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:247px;">6-0 Nylon suture&#160;</td>
			<td style="width:125px;">MWI</td>
			<td style="width:136px;">31849</td>
			<td></td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:247px;">Plastic Strips Band-Aid</td>
			<td style="width:125px;">Johnson &#38; Johnson</td>
			<td style="width:136px;"></td>
			<td>Obtained from pharmacy</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:247px;">10 cm Petri dish</td>
			<td style="width:125px;">Fisherbrand</td>
			<td style="width:136px;">FB0875712</td>
			<td></td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:247px;">PBS</td>
			<td style="width:125px;">Quality Biological</td>
			<td style="width:136px;">119069131</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:247px;">Buprenorphine</td>
			<td style="width:125px;"></td>
			<td style="width:136px;"></td>
			<td>DEA Number required; Obtained from hospital pharmacy</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:247px;">Enrofloxacin</td>
			<td style="width:125px;">Bayer Health Care</td>
			<td style="width:136px;">186599</td>
			<td></td>
		</tr>
	</tbody>
</table>

murine full-thickness skin transplantation

Murine full-thickness skin transplantation is a well-established in vivo model to study alloimmune response and graft rejection. Despite its limited application to humans, skin transplantation in mice has been widely employed for transplantation research. The procedure is easy to learn and perform, and it does not require delicate microsurgical techniques nor extensive training. Moreover, graft rejection in this model occurs in a very reproducible immunological reaction and is easily monitored by direct inspection and palpation. In addition, secondary skin transplantation with donor-matched or third-party skin grafts can be performed on more complex transplant models as an alternative and uncomplicated method to assess donor-specific tolerance. The complications are low and are in general limited to anesthesia overdose or respiratory distress after the procedure. Graft failure, on the other hand, occurs commonly as a result of poor preparation of the graft, incorrect positioning in the graft bed, or inappropriate placement of the bandage. In this article, we present a protocol for full-thickness skin transplantation in mice and describe the important steps necessary for a successful procedure.

The placement of the bandage on the recipient mouse is an important step of the procedure. The skin graft is positioned on the recipient trunk, between the shoulder, hip, and spine (Figure 1). The bandage is made with folded gauze and the combination of two plastic adhesive bandages. The recipient mouse is placed with the graft down over the gauze on the center of the bandage. Using two curved micro forceps, the lower end of the bandage is pulled first, and then the top of the bandage is wrapped over the mouse to the abdomen.
In complete mismatch models, full-thickness skin grafts are usually rejected in 8 to 12 days. In minor mismatch models, rejection responses are slower, more variable, and the skin graft appearance is characterized by less distinct changes, such as contraction or loss of hair (Figure 2). Acute graft rejection generally begins with swelling and erythema of the graft. These events are followed by graft desiccation, shrinkage, and scab formation (Figure 2B and C). Depending on the degree of MHC mismatch and the immunosuppression protocol, rejection can occur by a subacute process, marked by subtle changes such as loss of hair, pigmentation, dermal ridges, and graft volume. In these cases, a rejected graft appears shiny, white, and hairless, with uneven edges (Figure 2F)14.
Utilizing this model of skin transplantation, we investigated a novel approach targeting T-cell metabolism to prevent graft rejection15. It is well known that metabolic signaling pathways play critical roles in dictating the outcomes of T-cell responses16. Naive T cells rely on mitochondrial oxidative phosphorylation to generate the energy necessary for basic immune surveillance. However, upon activation, effector T cells metabolically reprogram to aerobic glycolysis and exhibit increased glutamine metabolism16,17. Using Balb/c as donors and C57BL/6 as recipients, we observed that inhibiting glycolysis and oxidative phosphorylation (2DG+metformin) or glutamine metabolism alone (DON) prolonged skin graft survival, but blocking the three pathways simultaneously resulted in significantly-increased graft survival (Figure 3C). Moreover, triple metabolic therapy was more effective than conventional cyclosporine or rapamycin (Figure 3A and B). Permanent acceptance was not achieved, and further strategies, including depletion therapy, costimulation blockade, or newer metabolic therapies, may promote better induction of transplant tolerance. However, the study provided two novel insights: the use of non-specific inhibitors to target selective immune cells with increased metabolic demands, as well as the requirement to block the three metabolic pathways simultaneously to obtain more robust immunosuppression in graft rejection.
Calcineurin inhibitors and mammalian target of rapamycin (mTOR) inhibitors constitute most of the conventional immunosuppressive therapy used in clinical transplantation. Median graft survival rates of Balb/c to C57BL/6 skin transplants treated with cyclosporine and rapamycin were 17 and 16 days, respectively. In comparison, recipients treated with metabolic inhibitors that inhibit T cell glycolysis, mitochondrial oxidative phosphorylation, and glutamine metabolism had prolonged survival: the median graft survival was 29 days. Furthermore, the histology of skin grafts from the metabolic therapy group exhibited more intact tissue alignment and less lymphocytic inflammatory infiltrate (Figure 4).
<img alt="Figure 1" src="/files/ftp_upload/55105/55105fig1.jpg" /> 
Figure 1: Covering of the Graft with the Bandage. (A) Skin graft placed on the right trunk. (B) Bandage made with a folded gauze and two plastic strips bandages. (C) Recipient mouse placed on the gauze. (D-F) Bandage wrapped around the mouse. <a href="https://cloudflare-jove-com.remotexs.ntu.edu.sg/files/ftp_upload/55105/55105fig1large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>
<img alt="Figure 2" src="/files/ftp_upload/55105/55105fig2.jpg" /> 
Figure 2: Skin Graft Appearance during Acute and Chronic Rejection. (A) Balb/c to C57BL/6 (complete mismatch) full-thickness skin transplantation without evidence of rejection (day 8). (B) Balb/c to C57BL/6 full-thickness skin transplantation with 50% graft rejection (day 13). (C) Balb/c to C57BL/6 full-thickness skin transplantation with complete graft rejection (day 18). (D) Syngeneic full-thickness skin transplantation (day 8). (E) Syngeneic full-thickness skin transplantation (day 30). (F) C57BL/10 to C57BL/6 (minor mismatch) full-thickness skin transplantation with chronic graft rejection (day 100).&#160; <a href="https://cloudflare-jove-com.remotexs.ntu.edu.sg/files/ftp_upload/55105/55105fig2large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>
<img alt="Figure 3" src="/files/ftp_upload/55105/55105fig3.jpg" /> 
Figure 3: Balb/c to C57BL/6 Skin Graft Survival. (A) Treatment with cyclosporine (25 mg/kg QD). (B) Treatment with rapamycin (3 mg/kg QD). (C) Treatment with metabolic inhibitors, 2-Deoxy-D-glucose (2DG) 500 mg/kg QD, metformin 150 mg/kg QD, and 6-Diazo-5-oxo-L-norleucine (DON) 1.6 mg/kg QOD. All treatments were administered from the day of transplantation until rejection. <a href="https://cloudflare-jove-com.remotexs.ntu.edu.sg/files/ftp_upload/55105/55105fig3large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>
<img alt="Figure 4" src="/files/ftp_upload/55105/55105fig4.jpg" /> 
Figure 4: Hematoxylin and Eosin Stain (right, X100; left, X200) of Skin Grafts with Metabolic Therapy at Postoperative Day 7. <a href="https://cloudflare-jove-com.remotexs.ntu.edu.sg/files/ftp_upload/55105/55105fig4large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>

Watch this Scientific Journal Video about Murine Full-thickness Skin Transplantation at JoVE.com

Murine Full-thickness Skin Transplantation

Murine full-thickness skin transplantation is a well-established model to study rejection in an alloimmune setting. Here, we provide a tutorial of each step involved in performing a BALB/c--&#62;C57BL/6 full-thickness skin transplant.

Murine full-thickness skin transplantation is a well-established in vivo model to study alloimmune response and graft rejection. Despite its limited ...

murine-full-thickness-skin-transplantation

Nanyang Technological University

Research

JoVE Journal

Immunology and Infection

19.9K Views.  Johns Hopkins University School of Medicine. Murine full-thickness skin transplantation is a well-established model to study rejection in an alloimmune setting. Here, we provide a tutorial of each step involved in performing a BALB/c-->C57BL/6 full-thickness skin transplant.

Video: Murine Full-thickness Skin Transplantation

Murine Model of CD40-activation of B cells

Research on B cells has shown that CD40 activation improves their antigen presentation capacity. When stimulated with interleukin-4 and CD40 ligand (CD40L), human B cells can be expanded without difficulties from small amounts of peripheral blood within 14 days to very large amounts of highly-pure CD40-B cells (&gt;109 cells per patient) from healthy donors as well as cancer patients1-4. CD40-B cells express important lymph node homing molecules and can attract T cells in vitro5. Furthermore they efficiently take up, process and present antigens to T cells6,7. CD40-B cells were shown to not only prime na&iacute;ve, but also expand memory T cells8,9. Therefore CD40-activated B cells (CD40-B cells) have been studied as an alternative source of immuno-stimulatory antigen-presenting cells (APC) for cell-based immunotherapy1,5,10. In order to further study whether CD40-B cells induce effective T cell responses in vivo and to study the underlying mechanism we established a cell culture system for the generation of murine CD40-activated B cells. Using splenocytes or purified B cells from C57BL/6 mice for CD40-activation, optimal conditions were identified as follows: Starting from splenocytes of C57BL/6 mice (haplotype H-2b) lymphocytes are purified by density gradient centrifugation and co-cultured with HeLa cells expressing recombinant murine CD40 ligand (tmuCD40L HeLa)11. Cells are recultured every 3-4 days and key components such as CD40L, interleukin-4, -Mercaptoethanol and cyclosporin A are replenished. In this protocol we demonstrate how to obtain fully activated murine CD40-B cells (mCD40B) with similar APC-phenotype to human CD40-B cells (Fig 1a,b). CD40-stimulation leads to a rapid outgrowth and expansion of highly pure (&gt;90%) CD19+ B cells within 14 days of cell culture (Fig 1c,d). To avoid contamination with non-transfected cells, expression of the murine CD40 ligand on the transfectants has to be controlled regularly (Fig 2). Murine CD40-activated B cells can be used to study B-cell activation and differentiation as well as to investigate their potential to function as APC in vitro and in vivo. Moreover, they represent a promising tool for establishing therapeutic or preventive vaccination against tumors and will help to answer questions regarding safety and immunogenicity of this approach12.

In this video, we demonstrate the procedure of CD40-activation and expansion of murine B cells from splenocytes of C57BL/6 mice, which can be used as a model antigen-presenting cell (APC) to study induction of immunity.

Research on B cells has shown that CD40 activation improves their antigen presentation capacity. When stimulated with interleukin-4 and CD40 ligand ...

Orthotopic Hind-Limb Transplantation in Rats

Composite tissue allotransplantation (CTA) now represents a valid therapeutic option after the loss of a hand, forearm or digits and has become a novel therapeutic entity in reconstructive surgery. However, long term high-dose multi-drug immunosuppressive therapy is required to ensure graft survival, bearing the risk of serious side effects which halters broader application. Further progression in this field may depend on better understanding of basic immunology and ischemia reperfusion injury in composite tissue grafts.
To date, orthotopic hind limb transplantation in rats has been the preferred rodent model for reconstructive transplantation (RT), however, it is an extremely demanding procedure that requires extraordinary microsurgical skills for reattachment of vasculature, bones, muscles and nerves.
We have introduced the vascular cuff anastomosis technique to this model, providing a rapid and reliable approach to rat hind limb transplantation. This technique simplifies and shortens the surgical procedure and enables surgeons with basic microsurgical experience to successfully perform the operation with high survival and low complication rates. The technique seems to be well suited for immunological as well as ischemia reperfusion injury (IRI) studies.

Here we describe the orthotopic rat hind-limb transplantation procedure, which seems to be the gold standard in vivo model for composite tissue allotransplantation research.

Composite tissue allotransplantation (CTA) now represents a valid therapeutic option after the loss of a hand, forearm or digits and has become a novel ...

Granulocyte-dependent Autoantibody-induced Skin Blistering

Autoimmune phenomena occur in healthy individuals, but when self-tolerance fails, the autoimmune response may result in specific pathology. According to Witebsky's postulates, one of the criteria in diagnosing a disease as autoimmune is the reproduction of the disease in experimental animals by the passive transfer of autoantibodies. For epidermolysis bullosa acquisita (EBA), a prototypic organ-specific autoimmune disease of skin and mucous membranes, several experimental models were recently established. In the animal model described in our present work, purified IgG antibodies against a stretch of 200 amino acids (aa 757-967) of collagen VII are injected repeatedly into mice reproducing the blistering phenotype as well as the histo- and immunopathological features characteristic to human EBA 1. Full-blown widespread disease is usually seen 5-6 days after the first injection and the extent of the disease correlates with the dose of the administered collagen VII-specific IgG. The tissue damage (blister formation) in the experimental EBA is depending on the recruitment and activation of granulocytes by tissue-bound autoantibodies 2,-4. Therefore, this model allows for the dissection of the granulocyte-dependent inflammatory pathway involved in the autoimmune tissue damage, as the model reproduces only the T cell-independent phase of the efferent autoimmune response. Furthermore, its value is underlined by a number of studies demonstrating the blister-inducing potential of autoantibodies in vivo and investigating the mechanism of the blister formation in EBA 1,3,-6. Finally, this model will greatly facilitate the development of new anti-inflammatory therapies in autoantibody-induced diseases. Overall, the passive transfer animal model of EBA is an accessible and instructive disease model and will help researchers to analyze not only EBA pathogenesis but to answer fundamental biologically and clinically essential autoimmunity questions.

In the animal model described in our present work, purified IgG antibodies against a stretch of 200 amino acids (aa 757-967) of collagen VII are injected repeatedly into mice reproducing the blistering phenotype as well as the histo- and immunopathological features characteristic to human epidermolysis bullosa acquisita (EBA)1.

Autoimmune phenomena occur in healthy individuals, but when self-tolerance fails, the autoimmune response may result in specific pathology. According to ...

Transplantation of Tail Skin to Study Allogeneic CD4 T Cell Responses in Mice

The study of T cell responses and their consequences during allo-antigen recognition requires a model that enables one to distinguish between donor and host T cells, to easily monitor the graft, and to adapt the system in order to answer different immunological questions. Medawar and colleagues established allogeneic tail-skin transplantation in mice in 1955. Since then, the skin transplantation model has been continuously modified and adapted to answer specific questions. The use of tail-skin renders this model easy to score for graft rejection, requires neither extensive preparation nor deep anesthesia, is applicable to animals of all genetic background, discourages ischemic necrosis, and permits chemical and biological intervention. 
In general, both CD4+ and CD8+ allogeneic T cells are responsible for the rejection of allografts since they recognize mismatched major histocompatibility antigens from different mouse strains. Several models have been described for activating allogeneic T cells in skin-transplanted mice. The identification of major histocompatibility complex (MHC) class I and II molecules in different mouse strains including C57BL/6 mice was an important step toward understanding and studying T cell-mediated alloresponses. In the tail-skin transplantation model described here, a three-point mutation (I-Abm12) in the antigen-presenting groove of the MHC-class II (I-Ab) molecule is sufficient to induce strong allogeneic CD4+ T cell activation in C57BL/6 mice. Skin grafts from I-Abm12 mice on C57BL/6 mice are rejected within 12-15 days, while syngeneic grafts are accepted for up to 100 days. The absence of T cells (CD3-/- and Rag2-/- mice) allows skin graft acceptance up to 100 days, which can be overcome by transferring 2 x 104 wild type or transgenic T cells. Adoptively transferred T cells proliferate and produce IFN-&#947; in I-Abm12-transplanted Rag2-/- mice.

Tail-skin transplantation is a powerful model for studying T cell-dependent rejection and tolerance induction during allogeneic immune responses in mice. The advantages of this protocol are minor invasive surgery, and ease of monitoring with no need to sacrifice the recipient mouse.

The study of T cell responses and their consequences during allo-antigen recognition requires a model that enables one to distinguish between donor and ...

Isolation and Transplantation of Different Aged Murine Thymic Grafts.

The mechanisms that regulate the efficacy of thymic selection remain ill-defined. The method presented here allows in vivo analyses of the development and selection of T cells specific for self and foreign antigens. The approach entails implantation of thymic grafts derived from various aged mice into immunodeficient scid recipients. Over a relatively short period of time the recipients are fully reconstituted with T cells derived from the implanted thymus graft. Only thymocytes seeding the thymus at the time of isolation undergo selection and develop into mature T cells. As such, changes in the nature and specificity of the engrafted T cells as a function of age-dependent thymic events can be assessed. Although technical expertise is required for successful thymic transplantation, this method provides a unique strategy to study in vivo a wide range of pathologies that are due to or a result of aberrant thymic function and/or homeostasis.

This report provides a detailed description of transplanting murine thymi from different aged donor mice under the kidney capsule of immunodeficient mouse recipients. The goal of this approach is to model T cell development and thymic selection events in vivo.

The mechanisms that regulate the efficacy of thymic selection remain ill-defined. The method presented here allows in vivo analyses of the development and ...

In Vitro and In Vivo Assessment of T, B and Myeloid Cells Suppressive Activity and Humoral Responses from Transplant Recipients

The main concern in transplantation is to achieve specific tolerance through induction of regulatory cells. The understanding of tolerance mechanisms requires reliable models. Here, we describe models of tolerance to cardiac allograft in rat, induced by blockade of costimulation signals or by upregulation of immunoregulatory molecules through gene transfer. Each of these models allowed in vivo generation of regulatory cells such as regulatory T cells (Tregs), regulatory B cells (Bregs) or regulatory myeloid cells (RegMCs). In this manuscript, we describe two complementary protocols that have been used to identify and define in vitro and in vivo regulatory cell activity to determine their responsibility in tolerance induction and maintenance. First, an in vitro suppressive assay allowed rapid identification of cells with suppressive capacity on effector immune responses in a dose dependent manner, and can be used for further analysis such as cytokine measurement or cytotoxicity. Second, the adoptive transfer of cells from a tolerant treated recipient to a newly irradiated grafted recipient, highlighted the tolerogenic properties of these cells in controlling graft directed immune responses and/or converting new regulatory cells (termed infectious tolerance). These methods are not restricted to cells with known phenotypic markers and can be extended to any cell population. Furthermore, donor directed allospecificity of regulatory cells (an important goal in the field) can be assessed by using third party donor cells or graft either in vitro or in vivo. Finally, to determine the specific tolerogenic capacity of these regulatory cells, we provide protocols to assess the humoral anti-donor antibody responses and the capacity of the recipient to develop humoral responses against new or former known antigens. The models of tolerance described can be used to further characterize regulatory cells, to identify new biomarkers, and immunoregulatory molecules, and are adaptable to other transplantation models or autoimmune diseases in rodent or human.

In Vitro and In Vivo Assessment of T, B and Myeloid Cells Suppressive Activity and Humoral Responses from Transplant Recipients

Here, we present a protocol to induce tolerance in transplantation, and assess in vitro and in vivo the suppressive capacity of distinct cell subsets from the recipient and the immune status of the recipient toward donor or exogenous antigens.

The main concern in transplantation is to achieve specific tolerance through induction of regulatory cells. The understanding of tolerance mechanisms ...

Using Robotic Systems to Process and Embed Colonic Murine Samples for Histological Analyses

The understanding of human diseases has been greatly expanded thanks to the study of animal models. Nonetheless, histopathological evaluation of experimental models needs to be as rigorous as that applied for human samples. Indeed, drawing reliable and accurate conclusions is critically influenced by the quality of tissue section preparation. Here, we describe a protocol for histopathological analysis of murine tissues that implements several automated steps during the procedure, from the initial preparation to the paraffin embedding of the murine samples. The reduction of methodological variables through rigorous protocol standardization from automated procedures contributes to increased overall reliability of murine pathological analysis. Specifically, this protocol describes the utilization of automated processing and embedding robotic systems, routinely used for the tissue processing and paraffin embedding of human samples, to process murine specimens of intestinal inflammation. We conclude that the reliability of histopathological examination of murine tissues is significantly increased upon introduction of standardized and automated techniques.

Lack of standardization for murine tissue processing reduces the quality of murine histopathological analysis as compared to human specimens. Here, we present a protocol to perform histopathological examination of murine inflamed and uninflamed colonic tissues to show the feasibility of robotic systems routinely used for processing and embedding&#160;human samples.

The understanding of human diseases has been greatly expanded thanks to the study of animal models. Nonetheless, histopathological evaluation of ...

Renal Subcapsular Transplantation of 2'-Deoxyguanosine-Treated Murine Embryonic Thymus in Nude Mice

The thymus is an important central immune organ, which plays an essential role in the development and differentiation of T cells. Thymus transplantation is an important method for investigating thymic epithelial cell function and T cells maturation in vivo. Here we will describe the experimental methods used within our laboratory to transplant 2&#8217;-deoxyguanosine (to deplete donor&#8217;s lymphocytes) treated embryonic thymus into the renal capsule of an athymic nude mouse. This method is both simple and efficient and does not require special skills or devices. The results obtained via this simple method showed that transplanted thymus can effectively support the recipient&#8217;s T cells production. Additionally, several key points with regards to the protocol will be further elucidated.

We provide a simple and efficient method to transplant 2&#8217;-deoxyguanosine treated E18.5 thymus into the renal capsule of a nude mouse. This method should aide in the study of both thymic epithelial cells function and T cells maturation.

The thymus is an important central immune organ, which plays an essential role in the development and differentiation of T cells. Thymus transplantation ...

Isolation of Lamina Propria Mononuclear Cells from Murine Colon Using Collagenase E

The intestine is the home to the largest number of immune cells in the body. The small and large intestinal immune systems police exposure to exogenous antigens and modulate responses to potent microbially derived immune stimuli. For this reason, the intestine is a major target site of immune dysregulation and inflammation in many diseases including but, not limited to inflammatory bowel diseases such as Crohn&#8217;s disease and ulcerative colitis, graft-versus-host disease (GVHD) after bone marrow transplantation (BMT), and many allergic and infectious conditions. Murine models of gastrointestinal inflammation and colitis are heavily used to study GI complications and to pre-clinically optimize strategies for prevention and treatment. Data gleaned from these models via isolation and phenotypic analysis of immune cells from the intestine is critical to further immune understanding that can be applied to ameliorate gastrointestinal and systemic inflammatory disorders. This report describes a highly effective protocol for the isolation of mononuclear cells (MNC) from the colon using a mixed silica-based density gradient interface. This method reproducibly isolates a significant number of viable leukocytes while minimizing contaminating debris, allowing subsequent immune phenotyping by flow cytometry or other methods.

The goal of this protocol is to isolate mononuclear cells that reside in the lamina propria of the colon by enzymatic digestion of the tissue using collagenase. This protocol allows for the efficient isolation of mononuclear cells resulting in a single cell suspension which in turn can be used for robust immunophenotyping.

The intestine is the home to the largest number of immune cells in the body. The small and large intestinal immune systems police exposure to exogenous ...

Optimization of the Cuff Technique for Murine Heart Transplantation

Murine cardiac transplantation has been performed for more than 40 years. With advancements in microsurgery, certain new techniques have been used to improve surgical efficiency. In our lab, we have optimized the cuff technique with two major steps. First, we used the inner tube technique to insert a temporary inner tube into the external jugular vein and carotid artery blood vessel to facilitate eversion of the vessel over the cuff. Second, we performed complete heterotopic cardiac transplantation through the collaboration of two experienced surgeons. These modifications effectively reduced the operation time to 25 minutes, with a success rate of 95%. In this report, we describe these procedures in detail and provide a supplemental video. We believe that this report on the improved cuff technique will offer practical guidance for murine heterotopic heart transplantation and will enhance the utility of this mouse model for basic research.

We introduce an inner tube approach to the cuff technique for mouse cervical heterotopic heart transplantation to help evert the vessel over the cuff. We found that cooperation between two experienced surgeons markedly shortens the operation time.

Murine cardiac transplantation has been performed for more than 40 years. With advancements in microsurgery, certain new techniques have been used to ...