Ex vivo cytokine and memory T cell responses to the 42-kDa fragment of Plasmodium falciparum merozoite surface protein-1 in vaccinated volunteers

Abstract

A number of blood-stage malaria Ags are under development as vaccine candidates, but knowledge of the cellular responses to these vaccines in humans is limited. We evaluated the nature and specificity of cellular responses in healthy American volunteers vaccinated with a portion of the major merozoite surface protein-1 (MSP1) of Plasmodium falciparum, MSP142, formulated on Alhydrogel. Volunteers were vaccinated three times with 80 μg of either MSP142-FVO/Alhydrogel or MSP142-3D7/Alhydrogel. Cells collected 2 wk after the third vaccination produced Th1 cytokines, including IFN-γ and IL-2 following Ag stimulation, and greater levels of the Th2 cytokines IL-5 and IL-13; the anti-inflammatory cy..