Murine epidermal Langerhans cells are potent stimulators of an antigen‐specific T cell response toLeishmania major, the cause of cutaneous leishmaniasis

摘要

AbstractCutaneous leishmaniasis is initiated by the bite of an infected sandfly and inoculation ofLeishmania majorparasites into the mammalian skin. Macrophages are knownto play a central role in the course of infection because they are the prime host cellsand function as antigen‐presenting cells (APC) for induction of the cell‐mediated immune response. However, in addition to macrophages in the dermis, the skin contains epidermal Langerhans cells (LC) which can present antigen (Ag) to T cells. Therefore, using a murine model of cutaneous leishmaniasis, we analyzed the ability of epidermal cells to induce a T cell response toL.major. The results demonstrated that freshly isolated LC, but not cultured LC, are highly active in presentingL.majorAgin vitroto T cells from primed mice and toaL.major‐specific T cell clone. Furthermore, freshly isolated LC had theability to retainL.majorAg in immunogenic form for at least 2 days. Their efficiency was much greater than that of irradiated spleen cells, a standard population of APC. LC stimulated both Tcell proliferation and production of the lymphokines interleukin (IL)‐2 and IL‐4. The response was Ag specific and could be induced by lysate ofL.majorparasites and by live organisms. The data suggest that epidermal LC are important APC in cutaneous leishmaniasis. They may perform a critical function by capturingL.majorAg in the skin and presenting it either to quiescent T cells circulating through the draining lymph node or locally to T effector cells infiltrating the cutaneo