Cellular changes and apoptosis in the spleens and peripheral blood of miceinfected with blood-stage Plasmodium chabaudi chabaudi AS

Infection with blood-stage Plasmodium chabaudi chabaudi AS results in splen omegaly, peripheral leukocytosis, and a major activation of the immune syst em. The frequencies and absolute numbers of T-cell, B-cell, and macrophage populations in spleen and peripheral blood from P. chabaudi-infected BALB/c mice were compared and found to be significantly altered during acute infe ction. The kinetics of the redistribution of the different cell types in sp leen and peripheral blood were different, with T and B cells appearing in t he blood when their frequencies and absolute numbers in the spleen were low . The frequency and absolute number of apoptotic cells in the spleen were i ncreased during acute P. chabaudi infection and involved both T cells, B ce lls, and macrophages. Both Fas and Fas-ligand expression were increased in the spleen. Taken together, our data provide new information on the complex cellular interactions that take place in the immune system during blood-st age malaria infection in a mouse model.