DIFFERENCES IN THE KINETICS OF T-CELL ACCUMULATIONS IN C3H HEN (BCG-RESISTANT) AND C57BL/6 (BCG-SUSCEPTIBLE) MICE INFECTED WITH MYCOBACTERIUM-PARATUBERCULOSIS/

The accumulation of various T cell subsets in Bcg-susceptible (C57BL/6 ) and -resistant (C3H/HeN) strains of mice were compared following an intraperitoneal infection with Mycobaeterium paratuberculosis. Groups of mice from both strains were killed at 3, 5, 10, 15, 30, and 150 day s after infection and lymphocytes were harvested from the peritoneal e xudate cells (PEG), spleen, intestinal epithelial lymphocytes (IEL), l amina propria lymphocytes (LPL), Peyer's patches, and mesenteric lymph node (MLN) and labelled with monoclonal antibodies to CD3, CD4, CD8, gamma delta TCR, CD25, and CD44 for flow cytometric analysis. Uninfect ed C3H/HeN mice had higher proportions of CD4+ cells in the spleen, ML N, LPL, IEL and Peyer's patches, while uninfected C57BL/6 mice had hig her proportions of CD8+ and/or gamma delta T cells. Significant increa ses in accumulation of CD8+ and gamma delta T cells were detected in t he peritoneum and other tissues in both strains of mice after infectio n. Higher CD4/CD8 ratios were observed in most lymphoid tissues of C3H /HeN mice, while increased proportions of CD8+ and/or gamma delta T ce ns were present in C57BL/6 mice. These results indicate that significa nt differences in T cell profiles exist between these two strains of m ice, both inherently and in response to infection with M. paratubercul osis. Innately lower levels of CD4+ cells and/or higher percentages of CD8+ and gamma delta T cells may play a role in the increased suscept ibility of C57BL/6 mice to infection with M. paratuberculosis. Copyrig ht (C) 1996 Elsevier Science Ltd.