Adult female mice of the ICR/JCL strain were injected intraperitoneally with an emulsion of Toxoplasma lysate antigen (TLA; 100 micrograms per head) in light mineral oil (LMO) twice at 2 weeks' interval. Each mouse was inoculated intraperitoneally with 10(2) erythrocytes infected with Babesia rodhaini 2 weeks after the second injection of the emulsion. The rates of decrease in the erythrocyte count, hemoglobin concentration, and hematocrit value 10 days after inoculation, as compared with the counterparts determined 1 day before inoculation, were distinctly lower in these treated mice than in untreated control mice. In the course of Babesia inoculations, substantial reduction in size and weight of the thymus became higher in untreated control than in TLA-treated mice as the infection progressed. In untreated controls, the number of Thy-1 positive (Thy-1 (+) ) cells was about 91.9% of the normal value being 3.7 X 10(7) cells in the whole thymus 1 day before inoculation while those in TLA-treated mice were 6.5 X 10(7) and 0.9 X 10(7) cells 1 day before inoculation and 10 days after inoculation, respectively. The size and weight of the spleen increased in both groups by day 10 after inoculation. The total number of Thy-1 (+) cells in the spleen was 3.9 X 10(7) and 11.7 X 10(7) 1 day before and 10 days after inoculations, respectively in untreated and 12.9 X 10(7) and 15.6 X 10(7), respectively in TLA-treated mice. The number of Thy-1 (+) cells in the liver was 0.5 X 10(7) and 1.2 X 10(7) 1 day before and 10 days after inoculations, respectively in untreated and 0.3 X 10(7) and 3.4 X 10(7), respectively, showing a rate increase of 1033.3% in TLA-treated mice. The rate of increase in count of Thy-1 (+) cells contained in the peripheral blood was 61.4% in the former and 64.1% in the latter. In untreated mice, degeneration and destruction of lymphocytes in the thymus and spleen follicles and aggregation of lymphocytes, which were not found in Thy-1 (+) staining, around pericapillary ducts in the liver were seen histopathologically 10 days after inoculation. In TLA-treated mice, however, perivascular infiltration by Thy-1 (+) lymphocytes and activation of Kupffer cells in the liver and activation of spleen follicles were observed locally 10 days after inoculation.
Animals Antibodies, Protozoan