Antibodies to food and environmental antigens in serum, respiratory tract and intestine of pigs

Serum antibodies to food, bedding and dust were detected in pigs by precipitation and ELISA. There was an age-related decrease in the number of animals with precipitating antibodies and in the specific activity of IgG and IgM antibodies. Antibodies to food, bedding and dust were detected in respiratory and intestinal secretions, but there were differences in the distribution and isotype of antibodies to these three antigens.