Protective immunity induced with malaria vaccine, RTS, S, is linked to Plasmodium falciparum circumsporozoite protein-specific CD4+ and CD8+ T cells producing IFN …

P Sun, R Schwenk, K White, JA Stoute… - The Journal of …, 2003 - journals.aai.org
P Sun, R Schwenk, K White, JA Stoute, J Cohen, WR Ballou, G Voss, KE Kester
The Journal of Immunology, 2003journals.aai.org
The Plasmodium falciparum circumsporozoite (CS) protein-based pre-erythrocytic stage
vaccine, RTS, S, induces a high level of protection against experimental sporozoite
challenge. The immune mechanisms that constitute protection are only partially understood,
but are presumed to rely on Abs and T cell responses. In the present study we compared CS
protein peptide-recalled IFN-γ reactivity of pre-and RTS, S-immune lymphocytes from 20
subjects vaccinated with RTS, S. We observed elevated IFN-γ in subjects protected by RTS …
Abstract
The Plasmodium falciparum circumsporozoite (CS) protein-based pre-erythrocytic stage vaccine, RTS, S, induces a high level of protection against experimental sporozoite challenge. The immune mechanisms that constitute protection are only partially understood, but are presumed to rely on Abs and T cell responses. In the present study we compared CS protein peptide-recalled IFN-γ reactivity of pre-and RTS, S-immune lymphocytes from 20 subjects vaccinated with RTS, S. We observed elevated IFN-γ in subjects protected by RTS, S; moreover, both CD4+ and CD8+ T cells produced IFN-γ in response to CS protein peptides. Significantly, protracted protection, albeit observed only in two of seven subjects, was associated with sustained IFN-γ response. This is the first study demonstrating correlation in a controlled Plasmodia sporozoite challenge study between protection induced by a recombinant malaria vaccine and Ag-specific T cell responses. Field-based malaria vaccine studies are in progress to validate the establishment of this cellular response as a possible in vitro correlate of protective immunity to exo-erythrocytic stage malaria vaccines.
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