HUMAN PBMC PROLIFERATIVE RESPONSE TO LEISHMANIA-INFANTUM PROMASTIGOTES IS INHIBITED BY ANTI-IFN-GAMMA MAB GAMMA-123

PBMC from individuals both exposed and non-exposed to leishmaniae prol iferative and produce interferon-gamma (IFN-gamma) following stimulati on with Leishmania antigens. We studied the kinetics of the proliferat ive response of PBMC from non-exposed individuals and from patients re covering from visceral leishmaniasis due to Leishmania infantum, using heat-killed stationary-phase promastigotes of L. infantum as stimulat ing agent. The kinetics of both groups followed a similar temporal pat tern, with higher values in the patient's group. Moreover, we observed that in both groups the activation was dose-dependently inhibited fol lowing the addition of gamma 123 anti-IFN-gamma monoclonal antibody. T hese results indicate the need for IFN-gamma in the activation process of PMBC induced by Leishmania antigens and stress the role of IFN-gam ma in the immune response to leishmaniasis. The relevance of the eluci dation of the immune response mechanism in human leishmaniasis for the rapy and vaccination is briefly discussed.