Characterization and functional analysis of skin-derived dendritic cells from swine without a requirement for in vitro propagation Elida M. Bautista, Douglas Gregg, William T. Golde * Foot-and-Mouth Disease Unit, Agricultural Research Service, USDA, Plum Island Animal Disease Center, P.O. Box 848, Greenport, NY 11944-0848, USA Received 28 January 2002; received in revised form 1 May 2002; accepted 1 May 2002 Abstract A low-density cell population was isolated from skin explants of pigs and characterized as a highly enriched dendritic cell (DC)populationbasedonphenotypicalandfunctionalproperties.Theskin-derivedDCswereidenti®edbytheircharacteristic ultrastructuralpropertiesaswellasbyconsistentco-expressionoftheCD1andSWC3aantigensthatclearlydifferentiatethem fromotherporcineleukocytes.ThesecellsexhibithigherexpressionofporcineMHCclassII(SLAII)andCD80/86antigensas comparedtomacrophage/monocytecells.TheyconsistentlyexpressedtheS100b antigenathighlevelsanddidnotexpressthe lymphoid markers CD3, CD4 or CD8. Within this population of skin-derived DCs there was variable expression of CD11c, CD14andCD16.FunctionalcharacterizationofthisDCpopulationrevealedthattheyareef®cientinuptakeandprocessingof solubleproteinantigensandinendocytosisofsmall(0.02 mm)butnotlarge(2 mm)polystyrenebeads.Further,thesecellswere ef®cient inducers of primary allogeneic responses and in stimulating antigen-speci®c and mitogen-induced proliferation and IFNg responses in autologous lymphocytes. This study provides important information to further characterize the cutaneous DCs and develop models to analyze the role of these cells in immune responses in vivo. Published by Elsevier Science B.V. Keywords: Dendritic cells; Swine; Antigen processing/presentation; Cell surface molecule 1. Introduction Dendritic cells (DC) play a central role in the induction and regulation of immune responses (Lan- zavecchia and Sallusto, 2001). Extensive knowledge of their phenotypic properties, ontogenic lineage and immunological functions has been derived from stu- dies using the mouse model (Anjuere et al., 1999; HeathandCarbone,2001;Henrietal.,2001;Hochrein et al., 2001). The properties and role of DCs in live- stock species is presently very limited much of the information derived from afferent lymph veiled cells (ALVC) of bovine and to a lesser extent other non- rodentspecies(reviewedby HowardandHope,2000). In vivo analyses of human DC populations are restricted due to ethical considerations. Knowledge ofhumanLangerhanscells(LC)isbasedonanalyses ofcells-derivedfromskinexplantsobtainedinplastic surgery, where extensive manipulation involving Veterinary Immunology and Immunopathology 88 (2002) 131±148 Abbreviations: AB, antibiotics; AM, alveolar macrophages; ASF, African swine fever; BEM, basal eagle medium; CFA, complete Freund's adjuvant; CSF, classical swine fever; CytC, cytochrome C; BrdU, bromo-deoxy uridine; DC, dendritic cell; FMD, foot-and-mouth disease; FS&SS, forward and side scatter analysis; IFA, incomplete Freund's adjuvant; LC, Langerhans cell; MdMO, monocyte-derived macrophages; MFI, mean ¯uorescence intensity; SLA, swine leukocyte antigen; SVD, swine vesicular disease; TEM, transmission electron microscopy * Corresponding author. Tel.: 1-631-323-3249 (O)/323-3285 (Lab); fax: 1-631-323-3295. E-mail address: wgolde@piadc.ars.usda.gov(W.T. Golde). 0165-2427/02/$ ± see front matter. Publishedby Elsevier Science B.V. PII:S0165-2427(02)00152-6