T cells from different subsets play a major role in protective immunity against pre-erythrocytic stages of malaria parasites. Exposure of humans and animals to malaria sporozoites induces (αβ CD8⁺ and CD4⁺ T cells specific for antigens expressed in pre-erythrocytic stages of Plasmodium. These T cells inhibit parasite development in the liver, and immunization with subunit vaccines expressing the respective antigenic moieties confers protection against sporozoite challenge. γδ and natural killer T cells can also play a role in protective immunity. Recent studies with mice transgenic for the αβ T-cell receptor have revealed the existence of complex mechanisms regulating the induction and development of these responses.