Onchocerciasis and immunity in humans: enhanced T cell responsiveness to parasite antigen in putatively immune individuals.
To identify possible immune mechanisms in human onchocerciasis, we compared a group of 12 individuals who had no clinical or parasitological evidence of infection, despite ongoing exposure to the parasite, with a group of 16 individuals from the same area who had active Onchocerca volvulus infection. Despite having less parasite-specific serum antibody, the infection-free ("putatively immune") individuals showed greater lymphocyte responsiveness, especially interleukin-2 (IL-2) production, to O. volvulus antigen (OVA) than did the infected subjects; lymphocyte responses (including IL-2 production) to mitogens and nonparasite antigen in both study groups were equivalent and normal. Our findings define differences in parasite-specific T cell subpopulations between infected and putatively immune subjects that could be a central element in developing or maintaining protective immunity to O. volvulus infection.
D000293:Adolescent; D000328:Adult; D000818:Animals; D000909:Antibodies, Helminth / Q000032:analysis; D000947:Antigens, Helminth / Q000276:immunology*; D005260:Female; D006801:Humans; D007371:Interferon-gamma / Q000096:biosynthesis; D007376:Interleukin-2 / Q000096:biosynthesis; D008213:Lymphocyte Activation; D008297:Male; D008875:Middle Aged; D009854:Onchocerca / Q000276:immunology*; D009855:Onchocerciasis / Q000276:immunology*; D013601:T-Lymphocytes / Q000276:immunology*
D000909:Antibodies, Helminth; D000947:Antigens, Helminth; D007376:Interleukin-2; D007371:Interferon-gamma