Specific precipitation of mouse and rat alpha 2-macroglobulin by immune sera directed against murine leukemia viruses.

Leukemia viruses preparations obtained from plasma of leukemic mice or rats were used to immunize rabbits. By immunoelectrophoresis, these non-absorbed antisera reacted specifically with one single mouse serum alpha 2 globulin which was further identified as alpha 2-macroglobulin by several criteria, including gel chromatography and nitracentrifugation. When mouse plasma derived virions were used as antigen, they gave rise to antibodies cross-reacting completely with the corresponding mouse and guinea pig protein and partially with rat and calf globulin. Immunization of rabbits with rat plasma derived virions induced antibodies directed preferentially against the rat alpha 2-macroglobulin.