Studies of bactericidal activity to Escherichia coli of porcine serum and colostral immunoglobulins and the role of lysozyme with secretory IgA

Abstract

Gel filtration and immune inhibition techniques were used to study bactericidal activities of IgG, IgM and IgA against smooth strains of Escherichia coli 0141 and 08 in sow serum and colostrum and post-colostral piglet serum. Bactericidal activity in sow sera was primarily associated with IgM and a low molecular weight IgG component, 7S IgG activity was less frequently observed. In colostral whey fractions and post-colostral piglet sera, in the absence of lysozyme, bactericidal antibody activity was associated with IgM and 7S IgG. In post-colostral serum bactericidal antibody was also attributable to a low molecular weight form of IgG.

IgA in serum from the sow and neonate showed no bactericidal activity, even in the presence of lysozyme, whereas in colostrum secretory 11S IgA had bactericidal activity, but only in the presence of complement and lysozyme.