Submitted to: Annual Conference on Vaccine Research
Publication Type: Abstract Only
Publication Acceptance Date: 11/20/2002
Publication Date: N/A
Technical Abstract: The present study was conducted to investigate the effect of age on cell-mediated immune responses to different antigens from Salmonella serovar Enteritidis (SE) following vaccination with the commercially available heat-the killed bacterin. Eight-month- and 4-week-old chickens were given two subcutaneous injections with SE bacterin at 2 weeks apart. At 4, 7, 11, 14, 18, and 21 days post immunization (PI), spleen lymphocytes were stimulated with Concanavalin (Con) A, heat-killed SE (HK-SE), LPS, flagella, outer membrane protein (OMP), and porin and their proliferation measured by a non-radioactive method using a tetrazolium salt, WST-8. Interferon (IFN-g) and interleukin-2 (IL-2) produced by spleen cells stimulated with different SE antigens and serum cytokine levels were assessed using an ELISA specific for cytokines. Vaccinated chickens of 4-week of age showed higher proliferation response to LPS and flagella antigen, but not to the other antigens, compared to the unvaccinated young chickens, whereas 8-month-old chickens showed a reduced proliferation response to SE antigens. Serum IFN-( and IL-2 levels were higher in the vaccinated birds compared to the age-matched control chickens regardless of the age group. The levels of IFN-( produced by the SE antigen-stimulated spleen cells were higher in the vaccinated young birds compared to the old chickens. These results indicate that various antigenic components of SE bacteria induce IFN-( and IL-2 production, and younger chickens show better T-lymphocyte-mediated immunity following SE vaccination .