Interleukin 10–Mediated Immunosuppression by a Variant CD4 T Cell Epitope of Plasmodium falciparum

Abstract

The immunodominant CD4 T cell epitope region, Th2R, of the circumsporozoite protein of Plasmodium falciparum is highly polymorphic. Such variation might be utilized by the parasite to escape from or interfere with CD4 T cell effector functions. Here, we show that costimulation with naturally occurring altered peptide ligands (APL) can induce a rapid change from IFNγ production to the immunosuppresive mediator interleukin 10 (IL-10). This mechanism may contribute to the low levels of T cell responses observed to this pathogen in malaria-endemic areas.