Comparative study of American cutaneous leishmaniasis and diffuse cutaneous leishmaniasis in two strains of inbred mice.

Two Leishmania strains, AZV (isolated from a typical case of American cutaneous leishmaniasis) and AMP (from a case of diffuse cutaneous leishmaniasis), were studied in C57BL/6 and BALB/c mice. After infection with 10(4) amastigotes of either strain, C57BL/6 mice developed self-resolving lesions lasting 20 to 23 weeks and showed both delayed hypersensitivity response to leishmanial antigen and specific agglutinating antibodies. On the other hand, BALB/c mice infected with 10(4) AZV or AMP amastigotes developed chronic, large, ulcerated lesions and showed impaired cellular and humoral responses to the parasite. When BALB/c and C57BL/6 mice received 10(2) AMP amastigotes, patterns of infection were similar to those observed after inoculation of 10(4) amastigotes. In vitro studies revealed that spleen cells from AZV- or AMP-infected C57BL/6 mice showed an increased DNA-synthetic response to leishmanial antigen, concanavalin A, and phytohemagglutinin. Spleen cells from AZV- or AMP-infected BALB/c mice showed an increased response to concanavalin A and diminished responses to leishmanial antigen, phytohemagglutinin, and lipopolysaccharide.