Leishmania amazonensis infection in nude mice

Leishmania amazonensis is an intracellular protozoan parasite of macrophage s. Cutaneous leishmaniasis in an immunocompetent host begins as papules or nodules followed by ulceration at the site of promastigote inoculation. In this study, the pathological changes of cutaneous leishmaniasis lesions in T cell deficient nude mice were examined. When infected with L. amazonensis promastigotes, nude mice developed non-ulcerative cutaneous nodules, By hi stological examination of cutaneous lesions, massive accumulation of vacuol ated histiocytes containing amastigotes was observed in all the nude mice. Although infiltration of mononuclear and polymorphonuclear cells was seen i n the lesions of immunocompetent mice, few such cells were observed in the lesions of nude mice. These results indicate the importance of T cells on t he ulcer formation in cutaneous leishmaniasis.