CD4 and malaria: These immune responses are critically dependent on α/β_CD4_ lymphocytes and established that T cells play a crucial role in the clearance of asexual blood-stage malaria parasites by activating the secretion of cytokines and that CD4 T cells constitute two functionally different subsets, i.e., Th1 (IFN-γ producing) and Th2 (interleukin-4 [IL-4]/IL-5-producing) cells.