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ASSOCIATION OF INTERFERON-γ RESPONSES TO PRE-ERYTHROCYTIC STAGE VACCINE CANDIDATE ANTIGENS OF PLASMODIUM FALCIPARUM IN YOUNG KENYAN CHILDREN WITH IMPROVED HEMOGLOBIN LEVELS: XV. ASEMBO BAY COHORT PROJECT

2003; American Society of Tropical Medicine and Hygiene; Volume: 68; Issue: 5 Linguagem: Inglês

10.4269/ajtmh.2003.68.590

1476-1645

John Michael Ong’echa, Altaf A. Lal, Feiko O. ter Kuile, Feiko O. ter Kuile, Simon Kariuki, Venkatachalam Udhayakumar, Alloys S. S. Orago, Allen W. Hightower, Bernard L. Nahlen, Ya Ping Shi,

Viral Infections and Vectors

Previous studies in animal models have revealed an association between interferon-γ (IFN- γ), produced by CD8 + T cells and irradiated sporozoite-induced sterile immunity. To determine whether IFN-γ can serve as a marker of pre-erythrocytic protective immunity in individuals naturally exposed to malaria, we characterized IFN-γ 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- γ positive responders had higher hemoglobin (Hb) levels and significantly reduced prevalence of severe malarial anemia one month after the test compared with IFN- γ non-responders, suggesting that IFN- γ 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- γ production could be used as a potential marker of protective immunity against malaria associated anemia in young children living in malaria holoendemic areas.