Antibodies to calf thymus RNA polymerase II from egg yolks of immunized hens

Polyclonal antibodies to calf thymus RNA polymerase II were raised in laying hens. Up to 75 mg of immunoglobulin/egg yolk were extracted by the polyethylene glycol procedure of Roeder (Roeder, R.G. (1976) in RNA Polymerase (Losick, R., and Chamberlin, M., eds) pp. 285-330, Cold Spring Harbor Laboratory, Cold Spring Harbor, NY). The concentration of specific antibody in egg yolks (IgY) was comparable to that of serum as measured by enzyme-linked immunoassay. Purified antibody was shown to be directed against enzyme by removal of enzyme activity in immune complexes precipitated by rabbit anti-chicken IgY. The antibodies recognized several of the subunits of the enzyme as determined by their reactivity with polypeptides transferred to nitrocellulose paper after gradient sodium dodecyl sulfate-gel electrophoresis. Production of antibodies in laying hens may facilitate the study of other highly conserved antigens that are poorly immunogenic in mammalian hosts.