Predominance of CD8+ T lymphocytes in the inflammatory lesions of mice with acute Trypanosoma cruzi infection.
Using glycol methacrylate in conjunction with avidin-biotin-peroxidase complex techniques, we studied the contribution of T cell subsets to tissue inflammation during acute Trypanosoma cruzi infection. Two mouse/parasite model systems whose parasitology and pathology behaved differently were used. In C57Bl/6J mice infected with the T. cruzi Brazil strain, the levels of parasitism in blood and tissue (myocardial and skeletal muscle) reached a maximum at week 6 and decreased rapidly thereafter. Inflammatory responses in tissue corresponded with the parasitism, but decreased in intensity more gradually than that of parasitism. The T lymphocytes (Thy 1.2+) were found to be the major lymphocyte population in inflammatory cardiac and skeletal muscles (64.6-81.2%) at both three and six weeks postinfection. Among T cells, CD8+ cells (47.0-58.9%) significantly outnumbered CD4+ cells (9.3-18.6%). The number of B cells (0-1.0%) and macrophages was low. Experiments using C3H/HeSnJ mice infected with the Sylvio X10/4 clone of T. cruzi at 30 days postinfection resulted in similar findings except for a higher CD8+:CD4+ ratio. The primary finding of this study is that Thy 1.2+CD8+CD4- T lymphocytes are the major cell population in both heart and skeletal muscle in acute murine T. cruzi infection. The predominance of CD8+ T cells coincident with the decrease in the tissue parasite burden suggests a role for CD8+ T cells in the control of T. cruzi at the level of the infected cell.
Sun
J
J
Department of Zoology, University of Georgia, Athens.
Tarleton
R L
RL
D000208:Acute Disease; D000818:Animals; D016516:CD4-CD8 Ratio; D014355:Chagas Disease / Q000276:immunology / Q000469:parasitology / Q000473:pathology*; D005260:Female; D006321:Heart / Q000469:parasitology; D007150:Immunohistochemistry; D016130:Immunophenotyping; D007249:Inflammation; D008214:Lymphocytes / Q000473:pathology; D008264:Macrophages / Q000473:pathology; D008297:Male; D051379:Mice; D008809:Mice, Inbred C3H; D008810:Mice, Inbred C57BL; D009132:Muscles / Q000469:parasitology / Q000473:pathology; D009206:Myocardium / Q000473:pathology; D013047:Specific Pathogen-Free Organisms; D013154:Spleen / Q000473:pathology; D050378:T-Lymphocytes, Regulatory / Q000276:immunology / Q000473:pathology / Q000502:physiology*; D014349:Trypanosoma cruzi / Q000254:growth & development