INDUCTION OF INTERLEUKIN-1-ALPHA IN MURINE MACROPHAGES INFECTED IN-VITRO WITH DIFFERENT SPECIES AND STRAINS OF LEISHMANIA

It is now generally agreed that several cytokines released by immunoco mpetent cells such as macrophages play a crucial role in the outcome o f infections caused by protozoa belonging to the genus Leishmania. In particular, tumor necrosis factor (TNF) induction during the course of cutaneous leishmaniasis has been related to resistance to L. major in fection in mice. However, the role played by interleukin 1 (IL-1) in t he host response to leishmaniasis has yet to be completely elucidated. The aim of this work was to study whether different species and strai ns of Leishmania could induce IL-1 alpha. in murine macrophages in vit ro. Resident peritoneal macrophages of BALB/c and C3H/HeN mice were in fected with L. donovani, L. major, or different strains of L. infantum . It was found that L. donovani did not induce IL-1 alpha in macrophag es from either mice strain. Infection with L. major or with three out of six strains of L. infantum induced consistent amounts of IL-1 alpha , but only in macrophages from genetically resistant C3H/HeN mice. No relationship was found between the rate of infection of macro phages a nd the amount of IL-1 alpha detected in the supernatants of infected m acrophages. Data obtained confirm that the release of IL-1 alpha by mu rine macrophages infected in vitro with Leishmania is influenced by th e genetic background of the cells as well as by the parasite species.