Plasmodium coatneyi: Differential clinical and immune responses of two populations of Macaca fascicularis from different origins

Two species of macaques, including two Macaca fascicularis from the Philipp ines, two M. fascicularis from Mauritius, and one Macaca mulatta, were expe rimentally infected with blood stages of Plasmodium coatneyi and followed d uring their clinical, parasitological, biological, and immunological evolut ion. Plasma cytokine (TNF-alpha, IL-1 beta, IL-6, IFN-gamma) production pea ked for all monkeys 11 days after inoculation, concomitantly with peaks of parasitemia. Only the M. fascicularis from the Philippines survived the inf ection. The main features, which discriminated nonfatal from fatal cases, w ere the observation in M. fascicularis from the Philippines of a mean CD4()/CD8(+) ratio below 1 and of their ability, as revealed by mitogenic stimu lation of whole blood, to produce increasing amounts of IFN-gamma as infect ion evolved. The contribution of environmental and genetic factors, which m ay differentiate the three groups of monkeys and therefore explain fatal or nonfatal evolution of the infection among them, is discussed. (C) 1999 Aca demic Press.