Antibodies to Escherichia coli J5 core glycolipids in gnotobiotic and conventionally reared piglets.

Antibody titers to Escherichia coli J5 endotoxin core glycolipids were determined in 5-week-old, unvaccinated, conventionally reared and gnotobiotic pigs in a micro-ELISA. Both groups of pigs had naturally occurring antibody of all major isotypes. The conventionally reared pigs had significantly (P less than 0.05) more serum antibody to J5 endotoxin glycolipids (geometric mean titer, GMT = 2.07) than gnotobiotes (GMT = 0.85). This relationship was not necessarily true in fluids from various anatomical structures. In gnotobiotes, mucosal-associated, anti-J5 glycolipid immunoglobulin was primarily IgM. In conventionally reared piglets, the mucosal-associated, anti-J5 glycolipid antibody contained more IgA. Such naturally occurring antibody could confer partial to complete immunity from challenge with Gram-negative bacteria.