Skin biopsies from psoriasis patients were kindly provided by Dr. Andreas Koerber (Dermatology department at University of Essen, Germany) after oral or written informed consent for scientific use.&#160;
X.H. is also supported by NSFC 61263039 and NSFC 11101321.

NOTE: Skin biopsies from healthy individuals were obtained from abdominal skin leftover of individuals undergoing elective plastic surgery after oral or written informed consent for scientific use. The use of human skin was approved and in accordance with the regulations set by the Medical Ethical Committees for human research of the Radboud university medical centre, Nijmegen, the Netherlands and University of Essen, Germany.
1. Preparation of Single Cell Suspensions from Human Skin (Work Sterile in a Flow-cabinet if Subsequent Cell Culture is Required)
<ol>
	<li>Prepare cell culture medium: RPMI 1640 + penicillin/streptomycin (final concentrations 100 units/ml and 100 &#181;g/ml, respectively) + pyruvate (0.02 mM) and glutamax (0.02 mM), with no serum added.</li>
	<li>Prepare complete culture medium: culture medium prepared in step 1.1 + 10% human pooled serum (HPS); store at 4&#176;C. Bring medium to 20 &#176;C &#177; 2 before using.</li>
	<li>Obtain the skin biopsy using a 4mm round biopsy punch instrument and keep it in RPMI1640 complete culture medium at 20 &#176;C &#177; 2 for up to 4 hr&#160;or at 4 &#176;C ON. Process the biopsy as soon as possible upon arrival in the laboratory. 
	NOTE: Longer storage of skin will influence the cell yield and cell viability.</li>
	<li>Label a blue-capped dissociation tube and add 5 ml complete culture medium into the labelled tube.</li>
	<li>Add 2 ml of complete culture medium into each well (in total 3 wells) of a sterile 6-well culture plate. Use sterile tools to place the biopsy into a single well, rinse, move it over to a second well and repeat this step one more time, thus achieving a total of three rinses.</li>
	<li>Transfer the well rinsed skin biopsy to a sterile Petri dish, add 100 &#181;l of complete culture medium on the top of biopsy, and carefully scrape off the subcutaneous fat tissue using a stainless steel disposable sterile scalpel. 
	NOTE: This is a critical step.</li>
	<li>Cut each skin biopsy into 4 smaller pieces on a sterile Petri dish. Transfer samples (up to four of 4 mm biopsies per tube) to the prepared dissociation tube containing 5 ml of complete culture medium.</li>
	<li>Tightly close the tubes with the cap, and attach upside down to the sleeve of the automated tissue dissociator. Make sure that all sample material is located in the area of the rotor.</li>
	<li>Start the dissociation process by running the &#8220;program m_spleen _01&#8221; (a pre-defined program provided by the instrument&#8217;s internal memory or by the accompanied program card) to dissociate the biopsy at the appropriate rotating speed for 56 sec.</li>
	<li>After processing, detach the dissociation tube from the dissociator and make sure that all the dissociated material is collected at the bottom of the tube.</li>
	<li>Add 150 &#181;l collagenase I-A (80 mg/ml) into the dissociation tube and incubate the sample in a shaking water bath at 37 &#176;C for 60 min. Add 100 &#181;l of DNase I (5 MU/ml) into thedissociation tube, mix well. 
	NOTE: Higher concentration of collagenase or longer incubation time will alter cell viability.</li>
	<li>Attach the dissociation tube to the sleeve of the automated tissue dissociator and run the &#8220;program m_ spleen _01&#8221; to dissociate the biopsy one more time.</li>
	<li>Place a 70 &#181;M nylon cell strainer on the top of a 50 ml Falcon tube. Apply dissociated sample materials to this cell strainer to remove cell clumps/tissue debris.</li>
	<li>Wash cell strainer once with 5 ml of complete culture medium. Centrifuge at 20 &#176;C &#177; 2, 450 x g for 10 min and aspirate supernatant.</li>
	<li>Repeat the washing step one more time. Resuspend cell pellets in 300 &#181;l of complete culture medium. Single-cell suspensions are ready for further analysis; continue with protocols for ex vivo cell culture or flow cytometry analysis.</li>
	<li>In case of further intracellular cytokine staining, stimulate cells with PMA (12.5 ng/ml), Ionomycin (500 ng/ml) and Brefeldine A (5 &#181;g/ml) for 4 hr&#160;at 37 &#176;C, 5% CO2 incubator for 4 hr&#160;before performing flow cytometry analysis.</li>
</ol>
2. Polyclonal Activation of Skin-Resident T Cells (Ex Vivo Cell Culture)
<ol>
	<li>Aliquot 100 &#181;l single-cell suspensions (prepared in step 1.15) into a round-bottom 96-well plate. 
	NOTE: For each of 4 mm skin biopsy, the acquired single-cell suspensions can be split into at least two wells of a 96-well plate.</li>
	<li>Add anti-CD3/anti-CD28 mAb-coated microbeads (25,000 beads per well), recombinant human cytokine rIL-2 (final concentration 25 U/ml) and rIL-1&#946; (final concentration 50 ng/ml).</li>
	<li>Cover the culture plate with a well-labelled plate lid, incubate in 5% CO2, 100% humidity, 37 &#176;C incubator. Change medium when the medium colour turns to yellow. 
	NOTE: A clear cell colony can be observed from day 8 of cell culture.</li>
</ol>
3. Flow Cytometry Analysis of Primary/Cultured Skin-Resident T Cells
<ol>
	<li>Prepare FACS buffer: PBS + 0.2% BSA.</li>
	<li>Transfer cells of interest into a v-bottom 96-well plate. Centrifuge at 20 &#176;C &#177; 2, 450 x g for 2 min, and aspirate supernatant.</li>
	<li>Resuspend the pellet in 100 &#181;l of PBS. Centrifuge at 20 &#176;C &#177; 2, 450 x g for 2 min, and aspirate supernatant.</li>
	<li>Stain cells with 100 &#181;l of prepared eFluorescence780 conjugated fixable viability dye (1:1,000 dilution using PBS) at 4 &#176;C for 30 min. Add 100 &#181;l of FACS buffer, centrifuge at 20 &#176;C &#177; 2, 450 x g for 2 min, and aspirate supernatant.</li>
	<li>Select required cell surface marker mAbs, for example: CD45-BV421 (HI30, 1:20), CD3-ECD(UCHT1, 1:50), CD4-PC5.5(1388.2, 1:200), CD8-APC-AlexFluo700(B9.11, 1:400), CD14-FITC(TUK4, 1:50), CD19-APC-AlexFluo750(13-119, 1:50), CD56-PE(MEM-188, 1:50), CD25-PeCy7(BC96, 1:50), CD11c-PeCy7(BU15, 1:10), and CD1c-APC(AD5-8E7, 1:10), prepare the mAbs-mixture using FACS buffer according to each mAb dilution factor tested. Define gate settings using isotype control of antibody together with non-stain sample.</li>
	<li>Add 25 &#181;l of prepared mAbs-mixture into each well. Incubate 20 min at 20 &#176;C &#177; 2, protect from light.</li>
	<li>Add 100 &#181;l of FACS buffer, centrifuge at 20 &#176;C &#177; 2, 450 x g for 2 min, and aspirate supernatant.</li>
	<li>For samples that only require cell surface staining, continue with step 3.16.</li>
	<li>In case of intra-cellular Foxp3 staining:
	<ol>
		<li>Prepare fixation and permeabilization buffer by mixing one part of concentrate with 3 parts of diluents.</li>
		<li>Prepare 1x permeabilization buffer: 1 part of 10x permeabilization buffer + 9 parts of sterilized H2O.</li>
	</ol>
	</li>
	<li>Resuspend pellets in 100 &#181;l of fixation and permeabilization buffer, mix well, and incubate at 4 &#176;C for 30 min.</li>
	<li>Add 100 &#181;l permeabilization buffer to each well, centrifuge at 450 x g at RT for 2 min, and aspirate supernatant.</li>
	<li>Wash cells with permeabilization buffer one more time.</li>
	<li>Select required intracellular mAbs, for example, Foxp3-eFluo450(PCH101, 1:50), IL-17A-AlexFluo488(eBio64DEC1, 1:50) and IFN&#947;-PeCy7(4S.B3, 1:400). Prepare the mAbs mixture using permeabilization buffer containing 2% normal rat serum according to each mAb dilution factor tested. Define gate settings using isotype control of antibody together with non-stain sample.</li>
	<li>Add 20 &#181;l of prepared mAb-mixture into each well. Incubate at 4 &#176;C for 30 min, protect from light.</li>
	<li>After 30 min incubation, add 100 &#181;l of permeabilization buffer into each well. Centrifuge at 20 &#176;C &#177; 2, 450 x g for 2 min, and aspirate supernatant.</li>
	<li>Wash cells with permeabilization buffer one more time. Resuspend pellet in 110 &#181;l of FACS buffer, and transfer cell suspensions into microFACS tube. 
	NOTE: Sample is ready for measurement using 10-colour flow cytometry.</li>
	<li>In case of exact cell number required, add 10 &#181;l of well-mixed uniform suspension of fluorospheres into each sample immediately before performing measurements using flow cytometry.</li>
</ol>

<ol>
	<li>Clark, R. A., 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=The+vast+majority+of+CLA++T+cells+are+resident+in+normal+skin.">The vast majority of CLA+ T cells are resident in normal skin.</a> J Immunol. 176, 4431-4439 (2006).</li><li>Zaba, L. C., Fuentes-Duculan, J., Steinman, R. M., Krueger, J. G., Lowes, M. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Normal+human+dermis+contains+distinct+populations+of+CD11c+BDCA-1++dendritic+cells+and+CD163+FXIIIA++macrophages.">Normal human dermis contains distinct populations of CD11c+BDCA-1+ dendritic cells and CD163+FXIIIA+ macrophages.</a> J Clin Invest. 117, 2517-2525 (2007).</li><li>Gebhardt, T., 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=Memory+T+cells+in+nonlymphoid+tissue+that+provide+enhanced+local+immunity+during+infection+with+herpes+simplex+virus.">Memory T cells in nonlymphoid tissue that provide enhanced local immunity during infection with herpes simplex virus.</a> Nature Immunol. 10, 524-530 (2009).</li><li>Boyman, O., 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=Spontaneous+development+of+psoriasis+in+a+new+animal+model+shows+an+essential+role+for+resident+T+cells+and+tumor+necrosis+factor-alpha.">Spontaneous development of psoriasis in a new animal model shows an essential role for resident T cells and tumor necrosis factor-alpha.</a> J Exp Med. 199, 731-736 (2004).</li><li>Christophers, E., Mrowietz, U. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+inflammatory+infiltrate+in+psoriasis.">The inflammatory infiltrate in psoriasis.</a> Clin Dermatol. 13, 131-135 (1995).</li><li>Jiang, X., 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=Skin+infection+generates+non-migratory+memory+CD8++T(RM)+cells+providing+global+skin+immunity.">Skin infection generates non-migratory memory CD8+ T(RM) cells providing global skin immunity.</a> Nature. 483, 227-231 (2012).</li><li>Havran, W. 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=Limited+diversity+of+T-cell+receptor+gamma-chain+expression+of+murine+Thy-1++dendritic+epidermal+cells+revealed+by+V+gamma+3-specific+monoclonal+antibody.">Limited diversity of T-cell receptor gamma-chain expression of murine Thy-1+ dendritic epidermal cells revealed by V gamma 3-specific monoclonal antibody.</a> Proc Natl Acad Sci U S A. 86, 4185-4189 (1989).</li><li>Campbell, J. 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=CCR7+expression+and+memory+T+cell+diversity+in+humans.">CCR7 expression and memory T cell diversity in humans.</a> J Immunol. 166, 877-884 (2001).</li><li>He, X., 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=Targeting+PKC+in+human+T+cells+using+sotrastaurin+(AEB071)+preserves+regulatory+T+cells+and+prevents+IL-17+production.">Targeting PKC in human T cells using sotrastaurin (AEB071) preserves regulatory T cells and prevents IL-17 production.</a> J Invest Dermatol. 134, 975-983 (2014).</li><li>Clark, R. A., 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+method+for+the+isolation+of+skin+resident+T+cells+from+normal+and+diseased+human+skin.">A novel method for the isolation of skin resident T cells from normal and diseased human skin.</a> J Invest Dermatol. 126, 1059-1070 (2006).</li><li>Clark, R. A., Kupper, T. S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=IL-15+and+dermal+fibroblasts+induce+proliferation+of+natural+regulatory+T+cells+isolated+from+human+skin.">IL-15 and dermal fibroblasts induce proliferation of natural regulatory T cells isolated from human skin.</a> Blood. 109, 194-202 (2007).</li><li>Keijsers, R. 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=In+vivo+induction+of+cutaneous+inflammation+results+in+the+accumulation+of+extracellular+trap-forming+neutrophils+expressing+RORgammat+and+IL-17.">In vivo induction of cutaneous inflammation results in the accumulation of extracellular trap-forming neutrophils expressing RORgammat and IL-17.</a> J Invest Dermatol. 134, 1276-1284 (2014).</li><li>Hybbinette, S., Bostrom, M., Lindberg, K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Enzymatic+dissociation+of+keratinocytes+from+human+skin+biopsies+for+in+vitro+cell+propagation.">Enzymatic dissociation of keratinocytes from human skin biopsies for in vitro cell propagation.</a> Experimental dermatology. 8, 30-38 (1999).</li><li>Hennino, A., 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=Skin-infiltrating+CD8++T+cells+initiate+atopic+dermatitis+lesions.">Skin-infiltrating CD8+ T cells initiate atopic dermatitis lesions.</a> J Immunol. 178, 5571-5577 (2007).</li></ol>

The authors have nothing to disclose.

Here, we present a protocol to efficiently isolate skin resident T cells from human skin biopsies. The advantage of this protocol is the isolation of relatively high numbers of viable lymphocytes, and expressing relevant surface markers. The cell subsets identified were: CD11c+ DCs, CD4+ and CD8+ T cells and Foxp3+CD25+ cells. Importantly, ex vivo culture of isolated skin resident T cells was very well feasible and allowed for subsequent functional analysis....

The skin, as the primary interface between the body and the environment, provides the first line of defence against external physical, chemical and biological insults such as wounding, ultraviolet radiation and micro-organisms. Skin comprises two main compartments, the epidermis and the dermis, and contains a variety of immune cells including Langerhans cells, macrophages, dendritic cells (DCs), and about 20 billion memory T cells, nearly twice the number present in the entire blood volume1,2. A growing body of data supports the notion that the skin has essential immunological functions, both during tissue homeostasis and in various pathological conditions. Immune cells resident in normal skin are thought to conduct immunosurveillance3 and have been shown to play a role in the development of inflammatory disorders such as psoriasis4. In psoriatic lesional skin, both CD4+ and CD8+ infiltrated T cells were observed and it was shown that the ratio of the CD4 and CD8 varies depending on the disease status5. However, these populations of cells are difficult to study because existing techniques allow the isolation of only few cells.
The currently widely used techniques for T cell isolation from human skin combine mechanical skin dissociation with enzymatic treatment. Human skin biopsies are extensively minced and incubated with enzymes like trypsin, collagenase and/or EDTA6-8. Considering that skin is a barrier tissue which is highly resistant to tensile forces and mechanical disaggregation, the established methods of T cell isolation produced very few cells, and even lower numbers of viable cells, which makes ex vivo cell culture of these cell populations difficult and challenging.
Here, we report a modified method to isolate lymphocytes from both healthy and involved psoriatic human skin by combining mechanical dissociation of the skin using an automated tissue dissociator instead of the established method of extensively mincing, together with enzymatic digestion using collagenase. Various viable immune cell subsets including DCs and T cells were observed after preparation of a single-cell suspension. Importantly the expression of the surface markers CD3, CD4 and CD8 was well preserved. Cells thus prepared, are ready for use in ex vivo cell cultures or flow cytometric analysis. This protocol has been successfully employed for the analysis of single skin biopsies (4 mm) derived from lesional skin of psoriasis patients. Results showed that skin resident patient T cells produced more inflammatory cytokines like IL-17 and IFN&#947; in comparison to healthy volunteers9.

<table border="0" cellpadding="0" cellspacing="0" width="843">
	<tbody>
		<tr height="21">
			<td height="21" style="height:21px;width:281px;">Name of Reagent/ Equipment</td>
			<td style="width:145px;">Company</td>
			<td style="width:119px;">Catalog Number</td>
			<td style="width:299px;">Comments/Description</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Disposable Biopsy Punch</td>
			<td>Kai Europe</td>
			<td>BP-40F</td>
			<td>4 mm</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Disposable sterile scalpels</td>
			<td>Dalhausen</td>
			<td>1100000510</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">gentleMACS C tube</td>
			<td>Miltenyi Biotech</td>
			<td>130-093-237</td>
			<td>Blue-capped, used as the dissociation tube.</td>
		</tr>
		<tr height="63">
			<td height="63" style="height:63px;width:281px;">gentleMACS Dissociator</td>
			<td>Miltenyi Biotech</td>
			<td>130-093-235</td>
			<td style="width:299px;">Automated tissue dissociator. Using the &#34;program spleen_01&#34; for dissociation of the skin biopsy.</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Cell strainer&#160;</td>
			<td style="width:145px;">BD</td>
			<td style="width:119px;">352350</td>
			<td>70 &#181;m nylon</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:281px;">96-well U-bottom plate</td>
			<td style="width:145px;">Greiner Bio-One</td>
			<td style="width:119px;">650180</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">RPMI 1640</td>
			<td>Life Technologies</td>
			<td>22409-015</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:281px;">Sodium pyruvate</td>
			<td>Life Technologies</td>
			<td>11360-039</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:281px;">GlutaMAX</td>
			<td>Life Technologies</td>
			<td style="width:119px;">35050-061</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:281px;">Penicillin/Streptomycin</td>
			<td>Life Technologies</td>
			<td>15140-122</td>
			<td></td>
		</tr>
		<tr height="24">
			<td height="24" style="height:24px;width:281px;">Human Pooled Serum (HPS)</td>
			<td style="width:145px;">in house prepared</td>
			<td style="width:119px;"></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:281px;">Collagenase I</td>
			<td>Sigma-Aldrich</td>
			<td style="width:119px;">C2674</td>
			<td>Type 1-A, suitable for cell culture</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:281px;">DNase I</td>
			<td style="width:145px;">Calbiochem</td>
			<td style="width:119px;">260913</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:281px;">PBS</td>
			<td style="width:145px;">B Braun</td>
			<td style="width:119px;">3623140</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:281px;">BSA</td>
			<td>Sigma-Aldrich</td>
			<td style="width:119px;">A4503-500G</td>
			<td></td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;">Fixable Viability Dye (FVD) APC-eFluo780</td>
			<td>eBioscience</td>
			<td>65-0865-18</td>
			<td style="width:299px;">Stain dead cells prior to cell fixation; dilute with PBS at 1:1000</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Fixation/Permeabilization Concentrate</td>
			<td>eBioscience</td>
			<td>00-5123-43</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Fixation/Permeabilization Diluent</td>
			<td>eBioscience</td>
			<td>00-5223-56</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Permeabilization Buffer (10x)</td>
			<td>eBioscience</td>
			<td>00-8333-56</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:281px;">BV421 Mouse anti-human CD45</td>
			<td style="width:145px;">BD</td>
			<td style="width:119px;">563879</td>
			<td>Clone: HI30; dilution factor 1:50</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:281px;">FITC Mouse anti-human CD14</td>
			<td>Dako</td>
			<td style="width:119px;">T0844</td>
			<td>Clone: TUK4; dilution factor 1:50</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:281px;">PE Mouse anti-human CD56</td>
			<td style="width:145px;">Dako</td>
			<td style="width:119px;">R7127</td>
			<td>Clone: MOC-1; dilution factor 1:50</td>
		</tr>
		<tr height="65">
			<td height="65" style="height:65px;width:281px;">ECD Mouse anti-human CD3</td>
			<td style="width:145px;">Beckman - Coulter</td>
			<td style="width:119px;">A07748</td>
			<td style="width:299px;">Clone: UCHT1; dilution factor 1:50 for surface staining; dilution factor 1:25 for intracellular staining.</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:281px;">PC5.5 Mouse anti-human CD4</td>
			<td style="width:145px;">Beckman - Coulter</td>
			<td style="width:119px;">B16491</td>
			<td>Clone: 13B8.2; dilution factor 1:200</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:281px;">PeCy7 Mouse anti-human CD11c</td>
			<td style="width:145px;">Beckman - Coulter</td>
			<td style="width:119px;">A80249</td>
			<td>Clone: BU15; dilution factor 1:50</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:281px;">APC Mouse anti-human CD1c</td>
			<td style="width:145px;">Miltenyi Biotech</td>
			<td style="width:119px;">130-090-903</td>
			<td>Clone: AD5-8E7; dilution factor 1:10</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:281px;">APC-AlexFluo700 Mouse anti-human CD8</td>
			<td style="width:145px;">Beckman - Coulter</td>
			<td style="width:119px;">A66332</td>
			<td>Clone: B9.11; dilution factor 1:400</td>
		</tr>
		<tr height="23">
			<td height="23" style="height:23px;width:281px;">APC-AlexFluo750 Mouse anti-human CD19</td>
			<td style="width:145px;">Beckman - Coulter</td>
			<td style="width:119px;">A94681</td>
			<td>Clone: J3-119; dilution factor 1:50</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:281px;">PeCy7 Mouse anti-human CD25</td>
			<td style="width:145px;">eBioscience</td>
			<td style="width:119px;">AD5-8E7</td>
			<td>Clone: BC96; dilution factor 1:50</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:281px;">&#160;PE Rat anti-human CLA</td>
			<td style="width:145px;">Miltenyi Biotech</td>
			<td style="width:119px;">130-091-635</td>
			<td>clone: HECA-452; dilution factor 1:</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;">eFluo450 Rat anti-human Foxp3</td>
			<td>eBIoscience</td>
			<td>48-4776-42</td>
			<td style="width:299px;">Clone: PCH101; intracellular staining; dilution factor 1:50</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:281px;">AlexFluo488 Mouse anti-human IL-17A</td>
			<td style="width:145px;">eBioscience</td>
			<td style="width:119px;">53-7179-42</td>
			<td style="width:299px;">Clone: eBio64DEC17; intracellular staining; dilution factor 1:50</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:281px;">PeCy7 Mouse anti-human IFNg</td>
			<td style="width:145px;">eBioscience</td>
			<td style="width:119px;">25-7319-41</td>
			<td style="width:299px;">Clone: 4S.B3; intracellular staining; dilution factor 1:400</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:281px;">Flow-Count Fluorospheres</td>
			<td style="width:145px;">Beckman - Coulter</td>
			<td align="right" style="width:119px;">7547053</td>
			<td>Counting beads, for flow cytometry</td>
		</tr>
	</tbody>
</table>

lymphocyte isolation from human skin for phenotypic analysis and ex vivo cell culture

Human skin has an important barrier function and contains various immune cells that contribute to tissue homeostasis and protection from pathogens. As the skin is relatively easy to access, it provides an ideal platform to study peripheral immune regulatory mechanisms. Immune resident cells in healthy skin conduct immunosurveillance, but also play an important role in the development of inflammatory skin disorders, such as psoriasis. Despite emerging insights, our understanding of the biology underlying various inflammatory skin diseases is still limited. There is a need for good quality (single) cell populations isolated from biopsied skin samples. So far, isolation procedures have been seriously hampered by a lack of obtaining a sufficient number of viable cells. Isolation and subsequent analysis have also been affected by the loss of immune cell lineage markers, due to the mechanical and chemical stress caused by the current dissociation procedures to obtain single cell suspension. Here, we describe a modified method to isolate T cells from both healthy and involved psoriatic human skin by combining mechanical skin dissociation using an automated tissue dissociator and collagenase treatment. This methodology preserves expression of most immune lineage markers such as CD4, CD8, Foxp3 and CD11c upon the preparation of single cell suspensions. Examples of successful CD4+ T cell isolation and subsequent phenotypic and functional analysis are shown.

The protocol presented here will yield between 2,200 &#177; 615 (mean &#177; SEM, skin of healthy volunteers) up to 178,000 &#177; 760 (mean &#177; SEM, lesional skin of psoriasis patients) viable lymphocytes from human skin when using a single 4 mm skin biopsy.
Different types of CD45+ cells were identified in single-cell suspensions derived from skin of healthy individuals including CD4+ T-cells (~45%), CD8+ T-cells (~30%), and CD11c+ DCs (~5%), wh...

Watch this Scientific Journal Video about Lymphocyte Isolation from Human Skin for Phenotypic Analysis and Ex Vivo Cell Culture at JoVE.com

Lymphocyte Isolation from Human Skin for Phenotypic Analysis and Ex Vivo Cell Culture

We describe a protocol to efficiently isolate skin resident T cells from human skin biopsies. This protocol yields sufficient numbers of viable human skin resident lymphocytes for flow cytometric analysis and ex vivo culture.

Lymphocyte Isolation from Human Skin for Phenotypic Analysis and Ex Vivo Cell Culture

Human skin has an important barrier function and contains various immune cells that contribute to tissue homeostasis and protection from pathogens. As the ...

lymphocyte-isolation-from-human-skin-for-phenotypic-analysis-ex-vivo

Research

JoVE Journal

Immunology and Infection

14.4K Views.  Radboud University Medical Centre. We describe a protocol to efficiently isolate skin resident T cells from human skin biopsies. This protocol yields sufficient numbers of viable human skin resident lymphocytes for flow cytometric analysis and ex vivo culture.

Video: Lymphocyte Isolation from Human Skin for Phenotypic Analysis and Ex Vivo Cell Culture

Human T Lymphocyte Isolation, Culture and Analysis of Migration In Vitro

The migration of T lymphocytes involves the adhesive interaction of cell surface integrins with ligands expressed on other cells or with extracellular matrix proteins. The precise spatiotemporal activation of integrins from a low affinity state to a high affinity state at the cell leading edge is important for T lymphocyte migration 1. Likewise, retraction of the cell trailing edge, or uropod, is a necessary step in maintaining persistent integrin-dependent T lymphocyte motility 2. Many therapeutic approaches to autoimmune or inflammatory diseases target integrins as a means to inhibit the excessive recruitment and migration of leukocytes 3. To study the molecular events that regulate human T lymphocyte migration, we have utilized an in vitro system to analyze cell migration on a two-dimensional substrate that mimics the environment that a T lymphocyte encounters during recruitment from the vasculature. T lymphocytes are first isolated from human donors and are then stimulated and cultured for seven to ten days. During the assay, T lymphocytes are allowed to adhere and migrate on a substrate coated with intercellular adhesion molecule-1 (ICAM-1), a ligand for integrin LFA-1, and stromal cell-derived factor-1 (SDF-1). Our data show that T lymphocytes exhibit a migratory velocity of ~15 &mu;m/min. T lymphocyte migration can be inhibited by integrin blockade 1 or by inhibitors of the cellular actomyosin machinery that regulates cell migration 2.

Human T Lymphocyte Isolation, Culture and Analysis of Migration In Vitro

T lymphocyte migration occurs during homing to lymphoid organs, exit from the vasculature, and entering into peripheral tissues. Here, we describe a protocol that can be used to analyze T lymphocyte migration in vitro.

The migration of T lymphocytes involves the adhesive interaction of cell surface integrins with ligands expressed on other cells or with extracellular ...

HLA-Ig Based Artificial Antigen Presenting Cells for Efficient ex vivo Expansion of Human CTL

CTL with optimal effector function play critical roles in mediating protection against various intracellular infections and cancer. However, individuals may exhibit suppressive immune microenvironment and, in contrast to activating CTL, their autologous antigen presenting cells may tend to tolerize or anergize antigen specific CTL. As a result, although still in the experimental phase, CTL-based adoptive immunotherapy has evolved to become a promising treatment for various diseases such as cancer and virus infections. In initial experiments ex vivo expanded CMV (cytomegalovirus) specific CTL have been used for treatment of CMV infection in immunocompromised allogeneic bone marrow transplant patients. While it is common to have life-threatening CMV viremia in these patients, none of the patients receiving expanded CTL develop CMV related illness, implying the anti-CMV immunity is established by the adoptively transferred CTL1. Promising results have also been observed for melanoma and may be extended to other types of cancer2. 
While there are many ways to ex vivo stimulate and expand human CTL, current approaches are restricted by the cost and technical limitations. For example, the current gold standard is based on the use of autologous DC. This requires each patient to donate a significant number of leukocytes and is also very expensive and laborious. Moreover, detailed in vitro characterization of DC expanded CTL has revealed that these have only suboptimal effector function 3. 
Here we present a highly efficient aAPC based system for ex vivo expansion of human CMV specific CTL for adoptive immunotherapy (Figure 1). The aAPC were made by coupling cell sized magnetic beads with human HLA-A2-Ig dimer and anti-CD28mAb4. Once aAPC are made, they can be loaded with various peptides of interest, and remain functional for months. In this report, aAPC were loaded with a dominant peptide from CMV, pp65 (NLVPMVATV). After culturing purified human CD8+ CTL from a healthy donor with aAPC for one week, CMV specific CTL can be increased dramatically in specificity up to 98% (Figure 2) and amplified more than 10,000 fold. If more CMV-specific CTL are required, further expansion can be easily achieved by repetitive stimulation with aAPC. Phenotypic and functional characterization shows these expanded cells have an effector-memory phenotype and make significant amounts of both TNF&alpha; and IFN&gamma; (Figure 3).

HLA-Ig Based Artificial Antigen Presenting Cells for Efficient ex vivo Expansion of Human CTL

A new DC independent method for induction and expansion of antigen-specific T cells is described. HLA A2-Ig based artificial Antigen Presenting Cells (aAPC) are loaded with HLA-A2 restricted peptides to efficiently expand CTL of diverse antigen specificity. This technology holds great potential for CTL-based adoptive immunotherapy.

CTL with optimal effector function play critical roles in mediating protection against various intracellular infections and cancer. However, individuals ...

Assessing the Innate Sensing of HIV-1 Infected CD4+ T Cells by Plasmacytoid Dendritic Cells Using an Ex vivo Co-culture System.

HIV-1 innate sensing requires direct contact of infected CD4+ T cells with plasmacytoid dendritic cells (pDCs). In order to study this process, the protocols described here use freshly isolated human peripheral blood mononuclear cells (PBMCs) or plasmacytoid dendritic cells (pDCs) to sense infections in either T cell line (MT4) or heterologous primary CD4+ T cells. In order to ensure proper sensing, it is essential that PBMC are isolated immediately after blood collection and that optimal percentage of infected T cells are used. Furthermore, multi-parametric flow cytometric staining can be used to confirm that PBMC samples contain the different cell lineages at physiological ratios. A number of controls can also be included to evaluate viability and functionality of pDCs. These include, the presence of specific surface markers, assessing cellular responses to known agonist of Toll-Like Receptors (TLR) pathways, and confirming a lack of spontaneous type-I interferon (IFN) production. In this system, freshly isolated PBMCs or pDCs are co-cultured with HIV-1 infected cells in 96 well plates for 18-22 hr. Supernatants from these co-cultures are then used to determine the levels of bioactive type-I IFNs by monitoring the activation of the ISGF3 pathway in HEK-Blue IFN-&#945;/&#946; cells. Prior and during co-culture conditions, target cells can be subjected to flow cytometric analysis to determine a number of parameters, including the percentage of infected cells, levels of specific surface markers, and differential killing of infected cells. Although, these protocols were initially developed to follow type-I IFN production, they could potentially be used to study other imuno-modulatory molecules released from pDCs and to gain further insight into the molecular mechanisms governing HIV-1 innate sensing.

Assessing the Innate Sensing of HIV-1 Infected CD4+ T Cells by Plasmacytoid Dendritic Cells Using an Ex vivo Co-culture System.

Unlike cell-free HIV-1 particles, infected CD4+ T cells are effectively sensed by plasmacytoid dendritic cells (pDCs). This manuscript describes a method where peripheral blood mononuclear cells (PBMCs) or isolated pDCs are co-cultured with HIV-1 infected T cells to evaluate innate sensing by pDCs as assessed by release of type-I IFN.

HIV-1 innate sensing requires direct contact of infected CD4+ T cells with plasmacytoid dendritic cells (pDCs). In order to study this process, the ...

Preparation of Single-cell Suspensions for Cytofluorimetric Analysis from Different Mouse Skin Regions

The skin is a barrier organ that interacts with the external environment. Being continuously exposed to potential microbial invasion, the dermis and epidermis home a variety of immune cells in both homeostatic and inflammatory conditions. Tools to obtain skin cell release for cytofluorimetric analyses are, therefore, very useful in order to study the complex network of immune cells residing in the skin and their response to microbial stimuli. Here, we describe an efficient methodology for the digestion of mouse skin to rapidly and efficiently obtain single-cell suspensions. This protocol allows maintenance of maximum cell viability without compromising surface antigen expression. We also describe how to take and digest skin samples from different anatomical locations, such as the ear, trunk, tail, and footpad. The obtained suspensions are then stained and analyzed by flow cytometry to discriminate between different leukocyte populations.

The skin is home to a complex immune cell network. We describe an efficient methodology for the digestion of mouse skin, from different parts of the animal's body, in order to obtain a single-cell suspension and analyze the different leukocyte populations resident in the skin by flow cytometry.

The skin is a barrier organ that interacts with the external environment. Being continuously exposed to potential microbial invasion, the dermis and ...

Isolation and Ex Vivo Culture of V&#948;1+CD4+&#947;&#948; T Cells, an Extrathymic &#945;&#946;T-cell Progenitor

The thymus, the primary organ for the generation of &#945;&#946; T cells and backbone of the adaptive immune system in vertebrates, has long been considered as the only source of &#945;&#946;T cells. Yet, thymic involution begins early in life leading to a drastically reduced output of na&#239;ve &#945;&#946;T cells into the periphery. Nevertheless, even centenarians can build immunity against newly acquired pathogens. Recent research suggests extrathymic &#945;&#946;T cell development, however our understanding of pathways that may compensate for thymic loss of function are still rudimental. &#947;&#948; T cells are innate lymphocytes that constitute the main T-cell subset in the tissues. We recently ascribed a so far unappreciated outstanding function to a &#947;&#948; T cell subset by showing that the scarce entity of CD4+ V&#948;1+&#947;&#948; T cells can transdifferentiate into &#945;&#946;T cells in inflammatory conditions. Here, we provide the protocol for the isolation of this progenitor from peripheral blood and its subsequent cultivation. V&#948;1 cells are positively enriched from PBMCs of healthy human donors using magnetic beads, followed by a second step wherein we target the scarce fraction of CD4+ cells with a further magnetic labeling technique. The magnetic force of the second labeling exceeds the one of the first magnetic label, and thus allows the efficient, quantitative and specific positive isolation of the population of interest. We then introduce the technique and culture condition required for cloning and efficiently expanding the cells and for identification of the generated clones by FACS analysis. Thus, we provide a detailed protocol for the purification, culture and ex vivo expansion of CD4+ V&#948;1+&#947;&#948; T cells. This knowledge is prerequisite for studies that relate to this &#945;&#946;T cell progenitor`s biology and for those who aim to identify the molecular triggers that are involved in its transdifferentiation.

Isolation and Ex Vivo Culture of V&#948;1+CD4+&#947;&#948; T Cells, an Extrathymic &#945;&#946;T-cell Progenitor

Here, we provide an optimized protocol for the isolation and cloning of the scarce T-cell entity of peripheral V&#948;1+CD4+ T cells that is, as we showed recently, an extrathymic &#945;&#946; T-cell progenitor. This technique allows to quantitatively isolate, clone and efficiently expand these cells in ex vivo culture.

The thymus, the primary organ for the generation of &#945;&#946; T cells and backbone of the adaptive immune system in vertebrates, has long been ...

Isolation of Infiltrating Leukocytes from Mouse Skin Using Enzymatic Digest and Gradient Separation

Dissociating murine skin into a single cell suspension is essential for downstream cellular analysis such as the characterization of infiltrating immune cells in rodent models of skin inflammation. Here, we describe a protocol for the digestion of mouse skin in a nutrient-rich solution with collagenase D, followed by separation of hematopoietic cells using a discontinuous density gradient. Cells thus obtained can be used for in vitro studies, in vivo transfer, and other downstream cellular and molecular analyses including flow cytometry. This protocol is an effective and economical alternative to expensive mechanical dissociators, specialized separation columns, and harsher trypsin- and dispase-based digestion methods, which may compromise cellular viability or density of surface proteins relevant for phenotypic characterization or cellular function. As shown here in our representative data, this protocol produced highly viable cells, contained specific immune cell subsets, and had no effect on integrity of common surface marker proteins used in flow cytometric analysis.

This protocol describes enzymatic digestion of mouse skin in nutrient-rich medium followed by gradient separation to isolate leukocytes. Cells thus derived can be used for diverse downstream applications. This is an effective, economical, and improved alternative to tissue dissociation machines and harsher trypsin and dispase-based tissue digestion protocols.

Dissociating murine skin into a single cell suspension is essential for downstream cellular analysis such as the characterization of infiltrating immune ...

Isolation and Flow Cytometric Analysis of Immune Cells from the Ischemic Mouse Brain

Ischemic stroke initiates a robust inflammatory response that starts in the intravascular compartment and involves rapid activation of brain resident cells. A key mechanism of this inflammatory response is the migration of circulating immune cells to the ischemic brain facilitated by chemokine release and increased endothelial adhesion molecule expression. Brain-invading leukocytes are well-known contributing to early-stage secondary ischemic injury, but their significance for the termination of inflammation and later brain repair has only recently been noticed.
Here, a simple protocol for the efficient isolation of immune cells from the ischemic mouse brain is provided. After transcardial perfusion, brain hemispheres are dissected and mechanically dissociated. Enzymatic digestion with Liberase&#160;is followed by density gradient (such as Percoll) centrifugation to remove myelin and cell debris. One major advantage of this protocol is the single-layer density gradient procedure which does not require time-consuming preparation of gradients and can be reliably performed. The approach yields highly reproducible cell counts per brain hemisphere and allows for measuring several flow cytometry panels in one biological replicate. Phenotypic characterization and quantification of brain-invading leukocytes after experimental stroke may contribute to a better understanding of their multifaceted roles in ischemic injury and repair.

Inflammation plays a central role in the pathogenesis of ischemic stroke. Increasing evidence suggests that it acts as a double-edged sword which exacerbates early brain injury, but also contributes to later repair. This protocol describes the isolation of immune cells from the ischemic brain and their subsequent flow cytometric phenotyping.

Ischemic stroke initiates a robust inflammatory response that starts in the intravascular compartment and involves rapid activation of brain resident ...

Murine Lymphocyte Labeling by 64Cu-Antibody Receptor Targeting for In Vivo Cell Trafficking by PET/CT

This protocol illustrates the production of 64Cu and the chelator conjugation/radiolabeling of a monoclonal antibody (mAb) followed by murine lymphocyte cell culture and 64Cu-antibody receptor targeting of the cells. In vitro evaluation of the radiolabel and non-invasive in vivo cell tracking in an animal model of an airway delayed-type hypersensitivity reaction (DTHR) by PET/CT are described.
In detail, the conjugation of a mAb with the chelator 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid (DOTA) is shown. Following the production of radioactive 64Cu, radiolabeling of the DOTA-conjugated mAb is described. Next, the expansion of chicken ovalbumin (cOVA)-specific CD4+ interferon (IFN)-&#947;-producing T helper cells (cOVA-TH1) and the subsequent radiolabeling of the cOVA-TH1 cells are depicted. Various in vitro techniques are presented to evaluate the effects of 64Cu-radiolabeling on the cells, such as the determination of cell viability by trypan blue exclusion, the staining for apoptosis with Annexin V for flow cytometry, and the assessment of functionality by IFN-&#947; enzyme-linked immunosorbent assay (ELISA). Furthermore, the determination of the radioactive uptake into the cells and the labeling stability are described in detail. This protocol further describes how to perform cell tracking studies in an animal model for an airway DTHR and, therefore, the induction of cOVA-induced acute airway DHTR in BALB/c mice is included. Finally, a robust PET/CT workflow including image acquisition, reconstruction, and analysis is presented.
The 64Cu-antibody receptor targeting approach with subsequent receptor internalization provides high specificity and stability, reduced cellular toxicity, and low efflux rates compared to common PET-tracers for cell labeling, e.g.64Cu-pyruvaldehyde bis(N4-methylthiosemicarbazone) (64Cu-PTSM). Finally, our approach enables non-invasive in vivo cell tracking by PET/CT with an optimal signal-to-background ratio for 48 h. This experimental approach can be transferred to different animal models and cell types with membrane-bound receptors that are internalized.

Murine Lymphocyte Labeling by 64Cu-Antibody Receptor Targeting for In Vivo  Cell Trafficking by PET/CT

Following the preparation of a 64Cu-modified monoclonal antibody binding to a transgenic murine T cell receptor, T cells are radiolabeled in vivo, analyzed for viability, functionality, labeling stability and apoptosis, and adoptively transferred into mice with an airway delayed-type hypersensitivity reaction for non-invasive imaging by positron emission tomography/computed tomography (PET/CT).

This protocol illustrates the production of 64Cu and the chelator conjugation/radiolabeling of a monoclonal antibody (mAb) followed by murine lymphocyte ...

Quantifying Human Monocyte Chemotaxis In Vitro and Murine Lymphocyte Trafficking In Vivo

Chemotaxis is migration along a specific chemical gradient1. Chemokines are chemotactic cytokines that promote cellular trafficking with anatomic and temporal specificity2. Chemotaxis is a critical function of lymphocytes and other immune cells that can be quantitatively assessed in vitro. This manuscript describes methods that permit the evaluation of chemotaxis, both in vitro and in vivo, for diverse cell types including cell lines and native cells. The in vitro, plate-based format permits the comparison of several conditions simultaneously in real-time, and can be completed within 1-4 h. In vitro assay conditions can be manipulated to introduce agonists and antagonists, as well as differentiate chemotaxis from chemokinesis, which is random movement. For in vivo trafficking assessments, immune cells can be labeled with multiple fluorescent dyes and used for adoptive transfer. The differential labeling of cells allows for mixed cell populations to be introduced into the same animal, thereby decreasing variance and reducing the number of animals required for an adequately powered experiment. Migration into lymphoid tissue occurs in as little as 1 h, and multiple tissue compartments can be sampled. Flow cytometry following tissue harvest allows for a rapid and quantitative analysis of the migratory patterns of multiple cell types.

Quantifying Human Monocyte Chemotaxis In Vitro and Murine Lymphocyte Trafficking In Vivo

Protocols for quantitative assessment of lymphocyte chemotaxis and migration are important tools for immunology research. Here, an in vitro protocol is described that permits real-time, multiplexed evaluation of cell migration, as well as a complementary in vivo technique enabling tracking of native cells to spleen.

Chemotaxis is migration along a specific chemical gradient1. Chemokines are chemotactic cytokines that promote cellular trafficking with anatomic and ...

Assessment of Lymphocyte Migration in an Ex Vivo Transmigration System

Herein, we present an efficient method that can be executed with basic laboratory skills and materials to assess lymphocyte chemokinetic movement in an ex vivo transmigration system. Group 2 innate lymphoid cells (ILC2) and CD4+ T helper cells were isolated from spleens and lungs of chicken egg ovalbumin (OVA)-challenged BALB/c mice. We confirmed the expression of CCR4 on both CD4+ T cells and ILC2, comparatively. CCL17 and CCL22 are the known ligands for CCR4; therefore, using this ex vivo transmigration method we examined CCL17- and CCL22-induced movement of CCR4+ lymphocytes. To establish chemokine gradients, CCL17 and CCL22 were placed in the bottom chamber of the transmigration system. Isolated lymphocytes were then added to top chambers and over a 48 h period the lymphocytes actively migrated through 3 &#181;m pores towards the chemokine in the bottom chamber. This is an effective system for determining the chemokinetics of lymphocytes, but, understandably, does not mimic the complexities found in the in vivo organ microenvironments. This is one limitation of the method that can be overcome by the addition of in situ imaging of the organ and lymphocytes under study. In contrast, the advantage of this method is that is can be performed by an entry-level technician at a much more cost-effective rate than live imaging. As therapeutic compounds become available to enhance migration, as in the case of tumor infiltrating cytotoxic immune cells, or to inhibit migration, perhaps in the case of autoimmune diseases where immunopathology is of concern, this method can be used as a screening tool. In general, the method is effective if the chemokine of interest is consistently generating chemokinetics at a statistically higher level than the media control. In such cases, the degree of inhibition/enhancement by a given compound can be determined as well.

In this protocol, lymphocytes are placed in the top chamber of a transmigration system, separated from the bottom chamber by a porous membrane. Chemokine is added to the bottom chamber, which induces active migration along a chemokine gradient. After 48 h, lymphocytes are counted in both chambers to quantitate transmigration.

Herein, we present an efficient method that can be executed with basic laboratory skills and materials to assess lymphocyte chemokinetic movement in an ex ...