Submitted to: Veterinary Immunology and Immunopathology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: June 12, 1999
Publication Date: N/A
Interpretive Summary: Understanding host immune response to enteric pathogens such as Salmonella is becoming important since Salmonella contaminated meat products can affect public health. In this study, ARS scientist collaborated with scientists at Osaka University in Japan to investigate the local immune response to Salmonella infection. The results showed that host lymphocytes, which are present in the reproductive immune system, play an important role in host resistance against Salmonella infection. These findings provide important basic information concerning Salmonella infection in poultry and will lay groundwork for future development of immunological control strategy against Salmonellosis.
Subsets of T lymphocytes, B. lymphocytes and macrophages in the ovaries and oviducts of laying hens were enumerated by immunohistochemistry after intravenous inoculation with Salmonella enteritidis. Almost all T cell subsets in the ovaries and different regions of the oviduct increased in number at 7 days post-inoculation and reached a peak by day 10. This T cell surge was followed by a peak in B cell numbers at day 14. The number of macrophages declined initially but recovered to preinoculation levels by day 21. At day 21, the numbers of T and B cells also returned to normal levels, except for IgG B cells in the infundibulum, isthmus, and vagina where they remained consistently elevated. The T and B cell proliferation at 10-14 days post- inoculation immediately proceeded a decline in recoverable S. enteritidis from the reproductive tract beginning at day 14 suggesting that these lymphocytes play a major role in the local immune response S. enteritidis. The Salmonella-oviduct model will be useful for future studies on local immunity to various infectious agents.