An enzyme-linked lectin sorbent assay (ELLSA) has been used to determine quantitatively the amount of soya-bean agglutinin (SBA) binding sites in and the sialic acid contents of small intestinal brush border membranes (BBM) of a group of 14 clinically healthy veal calves. Computer analysis of the results indicated 704 (s.e. 27) nmol SBA binding sites per mg of BBM protein with a Kj of 2·63 (s.e. 0·15) × 10-5mol/l; the sialic acid contents were 2·67 (s.e. 0·43) mg/g BBM protein. We could not demonstrate a correlation between the amount of binding sites and the sialic acid contents of the BBM.
Incubation with neuraminidase did not alter the number of SBA binding sites.