In vitro studies with lymphocytes from sheep orally inoculated with an aromatic-dependent mutant of Salmonella typhimurium.
It was previously shown that a live aroA-strain of Salmonella typhimurium of ovine origin was a safe and effective vaccine against salmonellosis in sheep. The protective effect was observed in the apparent absence of a detectable, systemic T cell response. In the present study, populations of B and T cells from the peripheral blood of sheep vaccinated with S25/1aroA were separated and their responsiveness in vitro to Salmonella was examined. The purified T cells proliferated very weakly in response to Salmonella in the absence of interferon-gamma and interleukin 2/4 production. However, whole peripheral blood mononuclear cells and purified B cells proliferated strongly in response to Salmonella, and Salmonella-specific IgM antibodies could be detected in cell supernatants. Furthermore, Salmonella-specific IgM-producing cells were detected at low frequency by enzyme linked immunospot techniques. These observations extend the earlier findings that oral vaccination with S25/1aroA primes predominantly antigen-specific B cells in the absence of strong Salmonella-specific T cell responses.
Brennan
F R
FR
Moredun Research Institute, Edinburgh.
Oliver
J J
JJ
Baird
G D
GD
D000284:Administration, Oral; D000818:Animals; D000907:Antibodies, Bacterial / Q000096:biosynthesis; D001402:B-Lymphocytes / Q000276:immunology; D001428:Bacterial Vaccines / Q000008:administration & dosage / Q000276:immunology*; D004797:Enzyme-Linked Immunosorbent Assay / Q000662:veterinary; D066298:In Vitro Techniques; D008214:Lymphocytes / Q000276:immunology*; D012486:Salmonella typhimurium / Q000235:genetics / Q000276:immunology*; D012756:Sheep / Q000276:immunology*; D013601:T-Lymphocytes / Q000276:immunology
D000907:Antibodies, Bacterial; D001428:Bacterial Vaccines