Immunochemical studies of infectious mononucleosis. III. Isolation and characterization of heterophile antibodies.

The heterophile antibody of infectious mononucleosis was isolated using an immunoabsorbent containing highly purified glycoprotein from horse erythrocyte membrane. Only the IgM fraction of this antibody agglutinated sheep erythrocytes or precipitated with the heterophile antigens from sheep, ox or horse red cells. The IgM antibody contained both κ and λ light chain determinants. The only reactivity which could be attributed to the IgG fraction of infectious mononucleosis serum was a slight degree of antigen binding by indirect radioimmunoelectrophoresis using 131I-labelled horse erythrocyte glycoprotein.