Submitted to: North Central Avian Disease Conference
Publication Type: Abstract Only
Publication Acceptance Date: 2/4/2001
Publication Date: N/A
Technical Abstract: Vaccination strategies for the prevention and eradication of Salmonella require further insight into the immunological mechanisms of infection, resistance to infection and elimination of Salmonella. We have attempted to examine the relative roles of some components of the local and systemic immune system after vaccination and infection with Salmonella. Four groups sof SOF leghorns were reared in separate isolation units for 4 weeks. The first group (n=8) was vaccinated with a live, avirulent vaccine strain at 1 day of age and received a booster dose at 14 days; the second (n=8), with an inactivated bacterin against various Salmonella species at the same time and interval as the first group; the third (n=8) was experimentally infected with a wild type Salmonella enteritidis (SE) PT4 at 1 day of age; the fourth (n=8) served as a control. Eight birds from each group were sacrificed and bled at 4 weeks of age. IgA, IgG, and IgM responses to Salmonella in serum and IgA in intestinal mucus were determined by isotype specific ELISA. Mean sample-to-positive (S/P) ratios of all three experimental groups were elvated at 4 weeks for all isotypes relative to the control. The two vaccinated groups showed higher serum antibody responses relative to the SE-infected group and control. Salmonella- specific IgA in the intestinal mucus at 4 weeks of age was detected in only 2/8 birds in the inactivated vaccine group. Intestinal IgA from the other groups were negligible.