Dynamics of lymphocyte subpopulation changes in the cecal tonsils of chickens infected with Salmonella enteritidis

Salmonella enteritidis (SE)-induced changes in various T and B lymphocyte subpopulations in the cecal tonsils of chickens were analyzed using flow cytometry. At 1 day post-SE inoculation, the percentages of CD3(+) and CD8(+) T lymphocytes were significantly decreased in the group inoculated with 1x10(9) SE colony-forming units (CFU) (SE high) and in the group inoculated with 1 x 10(6) SE CFU (SE low) compared with the uninfected control group. The percentage of CD4(+) T lymphocytes was significantly increased in the SE high group compared to the uninfected and the SE low groups at 4 days after SE inoculation. The percentage of IgG(+) B lymphocytes was also significantly increased in both SE high and low groups compared to the uninfected control at 6 days post-SE inoculation. In contrast, the SE low group showed significantly fewer IgM(+) B lymphocytes compared to the uninfected and SE high groups. These results show that SE infection induces significant changes in the cecal tonsil lymphocytes subpopulations shortly following SE inoculation. (C) 2000 Elsevier Science B.V. All rights reserved.