Immunological regulation of experimental cutaneous leishmaniasis. 2. Studies with Biozzi high and low responder lines of mice

Abstract

Susceptibility to Leishmania tropica was studied in Biozzi high (Ab/H) and low (Ab/L) responder mice of Selections I and III which, although originally selected with heterologous erythrocytes and Salmonella flagellar antigens, respectively, both show non-specific separation of antibody responses. Ab/H Sel I rapidly develop large, ulcerated, progressive, non-healing lesions (occasionally disseminating fatally) accompanied by rising serum antibody titers. Ab/L Sel I produce only small lesions, even with the largest infecting dose, which heal after 2 mo. with minimal antibody responses. Specific delayed-type hypersensitivity (DTH) levels found in both are normal and equivalent. (Ab/H .times. Ab/L)F1 mice behave intermediately. A smaller inter-line difference is only detectable in Sel III with lower infecting doses. Both Ab/L and Ab/H mice given high-doses develop chronic non-healing disease. Spontaneous resolution of cutaneous L. tropica lesions during the immune phase is independent of humoral antibody. While the great resistance and slower development of lesions found in Ab/L Sel I are entirely consistent with the macrophage hyperactivity characteristic of the line, attempts to demonstrate this in vitro with comparisons of infected peritoneal exudate cells were inconclusive.