Use of a synthetic hapten in the demonstration of the Thomsen-Friedenreich (T) antigen on neuraminidase-treated human red blood cells and lymphocytes.

Using an artificial T hapten, we have confirmed that human sera contain agglutinins for neuraminidase-treated red blood cells (N'RBC), specific for the disaccharide beta DGal(1 leads to 3)alpha DGalNAc. Further, we have shown that these agglutinins are antibodies largely of the IgM subclass that bind equally to neuraminidase-treated lymphocytes (N'lymphocytes). The anti-T antibody in human serum is cytotoxic for N'RBC in complement fixation assays. The synthetic hapten has biologic activity as shown in inhibition experiments and by the specificity of a rabbit antibody raised to the hapten for the naturally occurring antigen on N'RBC and N'lymphocytes. An immunoadsorbent prepared from the hapten was used to obtain biologically active antibodies from human serum with specificity for the naturally occurring antigen.