Identification of early cellular immune factors regulating growth of malaria parasites in humans.

In many host-parasite systems, regulatory T cells (CD4+, CD25+, FOXP3+) have been shown to modulate cellular immunity and pathology. In this issue of Immunity, Walther et al. have now shown that following experimental malaria infection of human volunteers, enhanced TGF-beta and T reg responses are associated with a faster parasite growth rate. The study demonstrates that regulation of cellular immunity must be addressed if we are to develop successful interventions.