CELL-MEDIATED-IMMUNITY AND PROTECTION AGA INST BLOOD STAGES OF PLASMODIUM-FALCIPARUM

In recent years, cell-mediated immunity against malaria has been the s ubject of intensive investigation either in humans from malaria endemi c areas, or experimental models. Cellular immune mechanisms have been regarded as secondary to humoral immunity but, there is increasing evi dence that shows its critical role in protection against blood stage p lasmodium parasites. In the context of a large humoral-cellular intera ction,T helper lymphocytes and monocytes/macrophages may play a key ro le in the elimination of plasmodial blood stages, particularly P. falc iparum. IL-2, IL-4, IL-5, IFN-gamma cytokines secreted principally by CD4+T lymphocytes and oxygen and nitrogen radicals produced by activat ed macrophages, are involved in the control of plasmodial infection. T he spleen also plays a very important function in the anti-malarial pr otection by its increased capacity for filtration/destruction of paras itized red blood cells and by induction of B and T memory lymphocytes. Successful vaccination against malaria needs a choice of plasmodial a ntigens or B and T immunodominants epitopes able to stimulate plasmodi um-specific lymphocytes and functional modification in the spleen.