Leishmania mexicana: Immunology and histopathology in C3H mice

Abstract

Leishmania mexicana: Immunology and histopathology in C3H mice. Experimental Parasitology 50, 45-56. C3H mice were infected subcutaneously with lo5 promastigotes of Leishmania mexicana and subsequent lesions were examined at 3, 5, and 8 months. All animals developed persistent nonulcerating nodules of variable size which did not metastasize. The nodules contained amastigotes with a mononuclear infiltrate of histiocytes, lymphocytes, and plasma cells, but without formation of tuberculoid-type granulomas. Neutrophils and eosinophils were also encountered in some cases. Specific antileishmanial antibodies and delayed-type hypersensitivity to leishmanial antigen were present at 3, 5, and 8 months postinfection. L. mexicana infection in C3H mice differs from classic self-healing cutaneous leishmaniasis by the persistence of nonhealing, nonulcerating, nonmetastasizing lesions, despite evidence of cellular and humoral immunity.