Visceral Leishmaniasis in the Golden Hamster as a Model for Human Kala-Azar

摘要

Leishmania donovani infection in the golden hamster was studied as a model for human kala azar. Following intradermal inoculation of L. donovani amastigotes, hamsters developed positive DTH responses to parasite antigens and expressed resistance to reinfection. Lymphoid cells from these hamsters responded to antigens in in vitro proliferation assays and transferred DTH reactivity to normal recipients. In contrast, hamsters inoculated intracardially with live amastigotes developed progressive visceral infections and failed to respond to skin-test antigens. Spleen cells, lymph node cells and peripheral blood cells (PBL) were unresponsive to parasite antigens in vitro and spleen cells failed to transfer DTH to recipient animals. Spleen and lymph node cells but not PBLs, also displayed depressed responses to mitogens. The addition of indomethacin or catalase failed to reconstitute proliferative responses. However, removal of adherent cells from populations of spleen but not lymph node and peripheral blood cells restored responsiveness to parasite antigens. Non-adherent spleen cells also transferred DTH to normal hamsters. These studies provide evidence that hamsters with visceral infections develop a population of antigen-reactive cells and that in the absence of suppression, these cells may express functional activities including DTH reactivity. Keywords: Immunity, Prostaglandins. (AW)