Parasitologic and immunologic studies of experimental Plasmodium falciparum infection in nonsplenectomized chimpanzees (Pan troglodytes).
Parasitologic, hematologic, and immunologic parameters were monitored in intact (nonsplenectomized), adult chimpanzees infected with a "chimp-adapted" strain of Plasmodium falciparum. Following primary and secondary injections of 10(9) P. falciparum-infected erythrocytes, each chimpanzee developed a low grade parasitemia (up to 1,000/mm3) and maintained the infection without evidence of eliminating the parasites. Hematologic and serum biochemical values, as well as the majority of immunologic parameters tested, remained unaltered in infected chimpanzees. However, 2 weeks after infection T cells from infected chimpanzees demonstrated an enhanced response in vitro to stimulation with the mitogen PHA, and monocyte phagocytic activity for antibody-coated erythrocytes (Fc-mediated phagocytosis) increased significantly. During malarial infection, apes developed a strong T cell proliferative response to P. falciparum antigens and monocytes showed enhanced phagocytic activity for P. falciparum-infected erythrocytes in the absence of immune serum. These results suggest that cellular immune mechanisms, especially macrophage activation, may help control, but not eliminate, P. falciparum malaria in chimpanzees.
D000818:Animals; D001402:B-Lymphocytes / Q000502:physiology; D005260:Female; D007074:Immunoglobulin G / Q000032:analysis; D007958:Leukocyte Count; D008213:Lymphocyte Activation; D008264:Macrophages / Q000502:physiology; D008288:Malaria / Q000276:immunology / Q000469:parasitology*; D008297:Male; D009000:Monocytes / Q000502:physiology; D002679:Pan troglodytes / Q000469:parasitology; D010587:Phagocytosis; D010963:Plasmodium falciparum; D013601:T-Lymphocytes / Q000502:physiology
D007074:Immunoglobulin G