Spleen cell changes during fatal and self-limiting malarial infections of mice

Changes in the proportions and total numbers of splenic Thy-1.2+ cells, Ig+ cells and normoblasts were analysed during fatal Plasmodium berghei and non-fatal P. yoelii infections in mice. Thy-1.2+ and Ig+ cells were identified by rosetting techniques, and normoblasts by morphological criteria. The splenomegaly observed during these infections was found to be caused mainly by proliferation of normoblasts. An early increase in the numbers of Thy-1.2+ and Ig+ cells was detected in both infections, but in P. berghei infections these responses were subsequently suppressed. In P. yoelii infections Thy-1.2+ and Ig+ cell numbers were maintained at four to five-fold above normal levels until the mice had completely recovered. During the acute phase of P. yoelii infection it appeared that most splenic T-cells expressed surface immunoglobulin.