IgA immunoglobulin from porcine serum

The isolation and immunologic characterisation of a porcine serum immunoglobulin is described. The isolated protein is shown to be distinct from IgG1, IgG2 and IgM but to share antigenic determinants with a colostral immunoglobulin, thought to be equivalent to human secretory IgA, which possesses additional determinants. It is suggested that the isolated serum immunoglobulin is equivalent to human serum IgA and that the pig possesses an IgA system analogous to that found in man.