Lymphocyte subpopulations and function in chronic murine toxoplasmosis.
A long-lasting, chronic infection with Toxoplasma gondii was established in C57Bl/6J mice as a model system of slow parasite infection. We quantified all nucleated cells and Thy-1+ and Thy-1- cell subpopulations in thymus, spleen and peripheral and mesenteric lymph nodes throughout the first 8 months of life of mice infected at 8 weeks of age. We found a physiological pattern of change with age in the lymphocyte subpopulations examined; the pattern was distinctive for each lymphoid organ. These normal patterns were altered in infected mice from the beginning of the observation period. The most prominent findings were (a) a relatively early atrophy of the thymus and (b) no increase in Thy-1+ lymphocyte numbers in either spleen or lymph nodes during the first 3 months post-infection, followed by decreasing numbers afterwards. Other findings were a rapid increase in the number of Thy-1- cells in the thymus before the onset of generalized atrophy; accumulation of erythrocytes in the spleen and splenomegaly during the first 3 months post-infection, despite a steady decrease in the number of nucleated cells; and an increase in Thy-1- cells in the peripheral but not in the mesenteric nodes, thereby diluting the Thy-1+ lymphocyte subpopulation.
D000375:Aging; D000818:Animals; D000961:Antilymphocyte Serum / Q000494:pharmacology; D005260:Female; D007958:Leukocyte Count; D008198:Lymph Nodes / Q000473:pathology; D008214:Lymphocytes / Q000145:classification* / Q000276:immunology; D008221:Lymphoid Tissue / Q000473:pathology*; D051379:Mice; D008810:Mice, Inbred C57BL; D013154:Spleen / Q000473:pathology; D013601:T-Lymphocytes / Q000276:immunology; D013950:Thymus Gland / Q000473:pathology; D014124:Toxoplasmosis, Animal / Q000276:immunology / Q000473:pathology*
D000961:Antilymphocyte Serum