Malaria: immunity and prospects for vaccination.

Malaria infections elicit a complex chain of cellular events which can, in some instances, lead to a state of immunity. Although there is strong evidence that a collaboration between specific antibodies and activated macrophages plays the central effector role in malaria immunity, alternative interpretations are possible. It is, for example, not known which malarial antigens are essential for triggering the critical effector functions and how these antigens are presented to the immune system. Under these circumstances, it is not surprising that the search for a vaccine against malaria has used rather empirical methods. Three invasive stages of the parasite (merozoites, sporozoites and gametes) have so far shown a potential efficiency in inducing protection in experimental models, but there is much to be done before vaccination can be an effective tool in malaria control.