[The place of beta-fetoproteins among other fetal proteins].

Beta1-Fetoprotein (Fbeta1) and fetal hemoglobin (HbF) were compared with the help of immunodiffusion methods. They were shown to be non-identical although Fbeta1, as well as HbF, is stained by benzidine. Antisera against Fbeta1 do not form the line of precipitation with HbF. Besides, we succeeded to differentiate Fbeta1 from Fbeta2 (they are separated under chromatography on sephadex G-200). Fbeta1 differs from Fbeta2 by benzidine staining: Fbeta1 is benzidine-positive and Fbeta2 is benzidine-negative. The constant parallelism in the appearance of Fbeta2 and a monomeric subunit IgMs of the immunoglobulin molecule IgM. Both the proteins, Fbeta1 and Fbeta2, are present in the serum of a newborn, as well as of a patient with ataxia-teleangiectasia. At the same time erythrocytes of the latter do not contain HbF, as was shown by electrophoresis in polyacrylamide gel.