Lysis of autologous macrophages pulsed with hsp10 from Mycobacterium leprae is associated to the absence of bacilli in leprosy

Peripheral blood mononuclear cells From leprosy patients and normal individ uals were analysed For their ability to lyse autologous macrophages pulsed with the Mycobacterium leprae 10 kDa heat shock protein (hsp10), an antigen considered to have an important rule in the protective responses in lepros y. Strong cytotoxic responses, with an involvement of gamma delta T and cla ss-I and class-II restricted alpha beta T cells and/or CD16 + 56 + cells, w ere observed in normal individuals. paucibacillary (PB) and those multibaci llary (MB) patients with undetectable bacillary load. On the contrary, only a weak class-II restricted cytotoxic response was observed in those MB pat ients with positive: bacillary load (MB(+)). simultaneous addition of IFN g amma plus TNF alpha and IL-12 during hsp10 stimulation could partially upre gulate the low cytotoxic response observed in MB(+) by enhancing class-II r estricted T cell activity and by development of gamma delta T and/or CD16 56 + cell activity. Our results suggest that the ability to mount an effec tive cytotoxic response against hsp10-pulsed macrophages in leprosy patient s is closely related to the patients bacterial load and not to the clinical form of the disease. (C) 2001 Elsevier science B.V. All rights reserved.