Blood stage parasites: Sufficient to induce protective immunity

Merozoites are the surface antigens and variant antigens expressed on the surface of malaria-infected erythrocytes (including PfEMPI) are both targets of protective antibody responses. The mechanism of the modified immune response was observed after subpatent infections. Subpatently infected mice had increased antigen-specific T-cell responses; they were not better protected than patently infected mice. The study of human volunteers, the absence of detectable malaria-specific antibodies probably reflects the extremely low parasite doses used for immunization. Induction of this type of immunity by immunizing with low doses of purified antigens from whole parasites may be an alternative but highly effective vaccine strategy.