Antibody response of the lactating sow to oral immunization with Escherichia coli.

Oral immunization of the lactating sow with live Escherichia coli (O8:K88) stimulated an IgA anti-K88 antibody response in mammary secretions and significantly enhanced the capacity of whey to inhibit adhesion of the inoculum E. coli strain to isolate pig enterocytes. An increase in agglutinating anti-O8 activity was also evident in jilk and was associated with both the IgA and IgM immunoglobulin classes. These results are consistent with the concept of a gut-mammary link, although measurement of specific antibody in the intestinal secretions of these animals suggested that there may be a difference in response duration at the two secretory sites. Prolonged oral administration of heat-killed organisms also stimulated specific antibody synthesis within the mammary gland, although the response, particularly to the O antigen, was both reduced and delayed in its appearance.