IMMUNE-RESPONSES IN CHICKENS AGAINST LIPOPOLYSACCHARIDE OF ESCHERICHIA-COLI AND SALMONELLA-TYPHIMURIUM

Immunization of chickens with whole bacteria results in the production of antibodies specific to lipopolysaccharide (LPS), a major constitue nt of the outer membrane of Gram-negative bacteria. However, there is relatively limited information available concerning immune response of purified LPS in this species. In the present study, immune responses were examined in serum and egg yolk from two groups of chickens inject ed with entire LPS from Escherichia coli and lipid A free LPS from Sal monella typhimurium. The results demonstrated that the increase of ant ibody activity occurs first in serum, and then in egg yolk with a lag in time of 1 to 3 wk in both groups of chickens. However, the time of elevated levels of antibody activity was much shorter in chickens immu nized with S, typhimurium LPS (< 1 wk) than in those immunized with E, coli LPS (4 wk). A lack of lipid A in the S, typhimurium antigen may be a factor related to this difference.