T-antigen (Gal β3 GaINAc α-) containing glycoproteins of human reace.

Desialation of cell surface glycoconjugates due to bacterial or viral infection can expose epitopes like T-antigenic structure which can also occur during oncological transformations. Human platelet plasma membrane glycoproteins were isolated by jacalin affinity chromatography. Potential T-antigen containing glycoproteins which were not reported before could be identified on the Western blot using peanut agglutinin-horse radish peroxidase (PNA-HRP) after neuraminidase treatment. Alpha-galactosyl epitopes recognized by anti-gal were found to be absent in human platelet plasma membrane glycoproteins. Under the experimental conditions employed, the Gp IIbα was identified most rich in T-antigenic structures. Probable role of exposed T-antigenic structures and α-galactosyl epitopes in pathological conditions is discussed. The identity of major glycoprotein bands was confirmed by differential lectin-binding studies with Concanavalin A on the Western blot. The higher binding affinity of jacalin for T-antigenic structures when compared to PNA enabled the isolation and detection of the antigen containing platelet surface glycoproteins which were not reported before.