Susceptibility of multipotent haemopoietic stem cell deficient W/Wv mice to Plasmodium berghei-infection.

The susceptibility of haemopoietic stem cell deficient W/Wv mice to infection with Plasmodium berghei was examined. The mean survival time of W/Wv mice after the infection was shorter than that of the +/+ mice. Splenomegaly, a characteristic pathological change of the host after infection with malaria parasites was not observed in W/Wv mice. When haemopoietic activity of the infected mice was examined, a substantial increase in number of multipotent haemopoietic stem cells (CFU-S) and the committed stem cells for granulocytes and macrophages (CFU-GM) or for erythrocytes (CFU-E) was observed in the bone marrow and spleen of +/+ but not of W/Wv mice. CFU-S were not detected in W/Wv mice before or after infection. The number of CFU-GM and CFU-E in bone marrow and spleen of W/Wv mice decreased after infection. Bone marrow grafting from +/+ to W/Wv mice 8 weeks before infection prolonged the mean survival time of the mice and effectively restored the number of CFU-S in the spleen of W/Wv mice. These results indicate that multi-potent haemopoietic stem cells play an important role in the host's defence mechanisms against P. berghei-infection.