CD4 and malaria: “Suppressor” cells—Tr1 (CXCR6+ CD127−), Treg (CD25+ CD127−), or T helper (Th) cells—were sorted from peripheral blood mononuclear cell (PBMC) samples of malaria-exposed Ugandan children and then co-cultured with allogenic “responder” memory CD4+ T cells for four days in the presence of αCD3 and αCD28 (Fig. 3A–B).