[Dynamics of splenic lymphocytes and immunosuppression in Toxoplasma infected mice (author's transl)].

Mice infected with high-virulent strains of T. gondii sustained a marked decrease of splenic lymphocytes within 7-10 days after infection, just prior to death. When infected with a low-virulent strain, the numbers of splenic lymphocytes and of T-lymphocytes fluctuated, but gradually increased over a period of 30 days. To evaluate their immunologic potential, the mice infected with a low-virulent strain of Toxoplasma were immunized with sheep erythrocytes on different days after infection, and antibody levels were measured by direct hemagglutination. Antibody response was minimal when sheep cells had been injected 10 days after infection with Toxoplasma; subsequently immunologic reactivity improved, but even after 30 days anti-sheep agglutinin titers were still below pre-infection levels.