Adsorption in vitro to Escherichia coli of antibodies and other proteins in bovine serum and colostrum and its effects on the production of E. coli agglutinins.

IgGl, IgG2, IgA and IgM from bovine serum and colostrum are adsorbed by Escherichia coli in vitro; lactoferrin is also adsorbed from colostrum and alpha2 macroglobulin from serum. The colostral adsorbed proteins on E. coli appear to reduce formation of agglutinins when the treated bacteria are injected into rabbits and guinea-pigs. Assay of the concentration of proteins dissociated from colostrum-treated cells showed equal amounts of secretory IgA AND IgGl, half that amount of IgG2, and traces of IgM and lactoferrin. Dissociation of proteins from serum-treated E. coli yielded equal amounts of IgGl and IgG2, traces of IgA and an alpha2 macroglobulin, but no IgM.