Physical interaction between Langerhans cells and T-lymphocytes during antigen presentation in vitro.
Physical interaction between Langerhans cells and T cells is an essential requirement for antigen presentation. In this study we report the ultrastructural characteristics of the antigen-specific physical interactions that occur in vitro between murine Langerhans cells and T cells. Epidermal Langerhans cells enriched to 78% purity by a panning method were pulsed with 2,4-dinitrophenyl-Limulus polyphemus hemocyanin and co-incubated with syngeneic T lymphocytes primed in vivo with the same antigen. A substantial number of conjugates constituted by Langerhans cells surrounded by three or more lymphocytes were obtained after 60 min of incubation at 4 degrees C. Electron microscopy of the conjugates revealed that Langerhans cells and T lymphocytes interacted by two type of contacts. Type I was characterized by glycocalyx-glycocalyx interaction that occurred in relation to protrusions or microvilli of both cells. Type II was characterized by wide and tight areas of close apposition between Langerhans cells and T-lymphocyte plasma membranes. In these areas there were zones with intercellular bridges and small septilaminar junctions highly suggestive of gap junctions. An electron-immunogold procedure demonstrated the presence of DNP-LPH antigen on the type I contact. Our findings suggest that type I contact may represent the locus for antigen presentation whereas the type II contact may be involved in keeping adhesiveness between Langerhans cells and lymphocytes during antigen presentation.
Instituto de Histología y Patología, Facultad de Medicina, Universidad Austral de Chile, Valdivia.
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D000818:Animals; D000938:Antigen-Presenting Cells / Q000166:cytology* / Q000187:drug effects; D002450:Cell Communication / Q000502:physiology; D002462:Cell Membrane / Q000276:immunology; D004136:Dinitrobenzenes / Q000494:pharmacology; D006433:Hemocyanins / Q000494:pharmacology; D000949:Histocompatibility Antigens Class II / Q000032:analysis; D007150:Immunohistochemistry; D007801:Langerhans Cells / Q000166:cytology / Q000276:immunology / Q000648:ultrastructure; D008297:Male; D051379:Mice; D008805:Mice, Inbred A; D008854:Microscopy, Electron / Q000379:methods; D013601:T-Lymphocytes / Q000166:cytology*
D004136:Dinitrobenzenes; D000949:Histocompatibility Antigens Class II; D006433:Hemocyanins