THE RESOLUTION OF ACUTE MALARIA IN A DEFINITIVE MODEL OF B-CELL DEFICIENCY, THE J(H)D MOUSE

Because the role of cell-mediated immunity (CMI) in the resolution of blood-stage malaria remains unclear, we examined the question of wheth er mice completely lacking Ab-mediated immunity (AMI) but possessing s ome CMI can resolve experimental malaria previously reported not to re quire AMI for resolution. Severe combined immunodeficient mice reconst ituted with enriched immune T cells (<0.5% B220(+) cells) suppressed a cute Plasmodium chabaudi adami parasitemia, suggesting that T, but not B, cells are required to clear this form of malaria. In addition, J(H )D mice, which are a definitive model of B cell deficiency, were also shown to resolve P. chabaudi adami, Plasmodium vinckei petteri and Pla smodium chabaudi chabaudi malaria. These observations collectively est ablish that CMI alone can mediate the clearance of acute malaria cause d by these subspecies of Plasmodium. Moreover, the protective cell-med iated immune response involved depends upon CD4(+) T cells because J(H )D mice treated with anti-CD4 mAb do not resolve their infections. The se results suggest that evaluation of immunization regimens to activat e CD4(+) T cell dependent cell mediated immunity against Plasmodium fa lciparum may be appropriate.