ABSTRACT
The K88 antigen of porcine enterotoxigenic Escherichia coli strains is a surface, filamentous, proteinaceous structure which promotes attachment of the organisms to the brush border surface of the epithelial cells, and thereby allows colonization of the small intestine. This chapter is concerned with the nature of the receptor on the brush borders of intestinal epithelial cells and also the characteristics of the binding mechanism. Attachment of K88-positive E. coli to brush borders can be seen when brush borders are mixed with K88-positive E. coli. The attachment can be inhibited completely with either cell free K88 antigen or with K88 antiserum. The K88 receptor appears to be a complex carbohydrate structure and the binding mechanism probably requires both a specific, possibly hydrophilic interaction and a much stronger possibly hydrophobic interaction. The first step may act as a key to initiate the second interaction since hydrophobic interactions do not appear to have great specificity.
