Porcine colostral IgA and IgM antibodies to Escherichia coli and their intestinal absorption by the neonatal piglet

Abstract

Antibodies against Escherichia coli 0141 and Escherichia coli 08 have been studied in porcine colostrum and serum using gel filtration and DEAE-cellulose chromatography. Immunoglobulins were assayed by radial immunodiffusion.

Immune inhibition studies with a rabbit anti-IgA-globulin serum showed that a high proportion of antibodies in colostrum measured by the antiglobulin haemagglutination test were associated with IgA. The IgA antibody could not be detected in sow serum where the antibody was almost entirely confined to IgM. Thus it appears that colostral IgA antibody was synthesized in the mammary gland.

Studies of the absorption of immunoglobulins and antibodies from colostrum in six litters of piglets showed that although IgA was absorbed from the colostrum, colostral IgA antibody to E. coli was not acquired as part of the passive immunity of the neonatal piglet.

The absorbed antibody was associated with IgM; another high molecular weight immunoglobulin 18S IgG was also absorbed.

It is suggested that structures on secretory IgA which correspond to cellular receptors for intestinal transmission may be blocked by the integration of secretory `piece'.