Submitted to: Poultry Science Association Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: May 1, 2002
Publication Date: N/A
This study was conducted to investigate the differential impact of live and killed Salmonella enteritidis (SE) vaccines on cell-mediated immunity of very young birds (2-5 weeks of age) as well as 16-week-old White Leghorn hens. The hens were vaccinated with the 2 vaccines, and two weeks later, CMI was assessed using splenic mononuclear cell proliferation, in response to Con A and antigen and cell subpopulation numbers as indices. Mitogen- and SE flagella- mediated proliferation and the cell populations were determined by 3H-thymidine uptake and flow cytometry, respectively. Con A-mediated response was generally higher in the live vaccine group compared to the control and the killed vaccine treated groups. Splenic lymphocyte proliferation to Con A was significantly lower in the killed vaccine group of all the younger birds tested, compared to the control group. SE-flagella mediated splenic lymphocyte response was very low and variable among the young birds. These changes in the function were accompanied by some transient changes in the cell populations. Con-A mediated and the SE flagella-mediated proliferation were enhanced in the 16-week-old birds vaccinated with live vaccine, compared to the corresponding control birds. However, Con A-mediated response was higher in the killed vaccine group of only the 16-week old birds compared to the corresponding control birds. These functional changes were accompanied by increased CD4 and decreased CD8 populations in the live vaccine group. Overall, live vaccine appeared to result in a greater proliferation of splenic lymphocytes in very young birds. Thus, live vaccine may prove beneficial in protecting hens that are infected with the wild type SE, since CMI plays an important role in protection against SE infection.