Association of Interferon-gamma Responses to Pre-erythrocytic Stage Vaccine Candidate Antigens of Plasmodium Falciparum in Young Kenyan Children with Improved Hemoglobin Levels: XV. Asembo Bay Cohort Project.

Thumbnail Image
Ong'echa, J. M.
Lal, A. A.
Terlouw, D. J.
Ter Kuile, F. O.
Kariuki, S. K.
Udhayakumar, V.
Orago, A. S.
Hightower, A. W.
Nahlen, B. L.
Shi, Y. P..
Journal Title
Journal ISSN
Volume Title
The American Journal of Tropical Medicine and Hygiene
Previous studies in animal models have revealed an association between interferon-gamma (IFN-gamma), produced by CD8+ T cells and irradiated sporozoite-induced sterile immunity. To determine whether IFN-gamma can serve as a marker of pre-erythrocytic protective immunity in individuals naturally exposed to malaria, we characterized IFN-gamma and lymphocyte proliferative responses to previously defined CD8+ cytotoxic T lymphocyte (CTL) epitopes from six pre-erythrocytic stage antigens in 107 children six months to two years old from a community-based birth cohort in western Kenya. We found that IFN-gamma positive responders had higher hemoglobin (Hb) levels and significantly reduced prevalence of severe malarial anemia one month after the test compared with IFN-gamma non-responders, suggesting that IFN-gamma immune responses to these pre-erythrocytic antigens were associated with protection against malarial anemia. Children who responded by lymphocyte proliferation had a significantly longer time to first documented malaria parasitemia after birth; however, there was no correlation between the presence of lymphocyte proliferative response and higher Hb levels. We propose that IFN-gamma production could be used as a potential marker of protective immunity against malaria associated anemia in young children living in malaria holoendemic areas.
Am J Trop Med Hyg. 2003 May;68(5):590-7.