[CA antibodies (Enterobacteriaceae common antigen) in the sera of domestic animals].

Using the indirect hemagglutination test, antibodies against Enterobacteriaceae common antigen (CA) were tested in the sera of 123 horses, 142 cows, 108 sheep, 142 mature pigs and 60 piglets (3-4 weeks of age). Anti CA antibody level and antibody titers for somatic antigens (phenol-water extracts) various serogroups of E. coli (0149, 0138, 0115, 078, 09) and S. typhimurium were compared. Ca antibodies in titer equal or higher than 1:15 were found to occur in 100% of the examined horses and cows, while in the sera of 92% sheep, 80% of mature pigs and 60% of piglets antibodies to the common Enterobacterial antigen were present in titer equal or higher than 1:7.5. In all sera examined the antibody level to somatic antigens of E. coli and S. typhimurium exceeded that to Enterobacteriaceae common antigen. The influence of absorption of sera with CA preparation on the antibody level to heterologous antigens was also examined. It was found that the absorption caused a statistically significant decrease of the titers to O antigens E. coli and S. typhimurium in comparison with those found in unabsorbed sera.