Characterization of Thomsen-Friedenreich Antibody Subpopulations from Normal Human Serum

Abstract

Thomsen-Friedenreich (TF) antibodies were prepared from human serum by different enrichment procedures. This resulted in three antibody preparations all of which agglutinated neuraminidase-treated erythrocytes. On the other hand, each of the three antibody populations showed a distinct specificity pattern. Anti-TF1 antibodies could be inhibited in the hemagglutination inhibition assay by asialofetuin, asialotransferrin, asialoglyco-phorin and asialomucin. The sialylated form of these glycoproteins showed no inhibition. No significant inhibition could be achieved with several mono- or disaccharides. This suggests that anti-TF1 recognizes common structures on glycoproteins normally hidden by sialic acid. Anti-TF2 antibodies showed specificity for asialofetuin, bovine submaxillary mucin, asialomucin, asialoglycophorin, the disaccharide gal-β(l-3)N-acetyl-galactosamine (galNAc) and nitrophenyl-β-galactoside. Because asialotransferrin or unbound lactosamine were not inhibitory, we suppose that the residual common structure of the inhibitors is (gal)-galNAc-O-Ser/Thr, which is present in high amounts in submaxillary mucin. Anti-TF3 antibodies were inhibited by asialoglycophorin but not by asialomucin or asialofetuin. Strong saccharide inhibitors were gal-β(l-3)galNAc, nitrophenyl-β-galactoside, as well as galactose. Therefore, both of the antibody preparations, anti-TF2 and anti-TF3, could be inhibited by gal-β-( 1– 3)galNAc, but showed preference to one or the other sugar component of the disaccharide resulting in a differential recognition of glycoconjugate inhibitors. Anti-TF2 and anti-TF3 seem to recognize the carbohydrates in the context of a protein backbone, because gal-β-(l-3)galNAc in connection with a ceramide backbone (GMj) was not inhibitory. When tested on three human breast cancer cell lines, only anti-TF2 recognized epitopes exposed on the cell surface. We, therefore, conclude that human serum contains at least three subpopulations of TF antibodies with distinct specificities. Only anti-TF2 can detect cryptic eryth-rocyte epitopes which are also exposed on human breast cancer cell lines.

Increased Expression of Thomsen-Friedenreich Antigens during Tumor Progression in Breast Cancer Patients

“…Several groups have demonstrated the presence of TF antigens in carcinoma as well as in lymphoma cells [1,[3][4][5][6]. Antisera and lectins were used for their detection and it was shown that these reagents bind to differ ent epitopes on the cell membrane or to structures in the cytoplasm [3,14], The use of peanut agglutinin in breast cancer tissue resulted in an overall staining of cancerous tissue regardless of tumor stage as well as structures in normal tissue [15,16] [unpubl.…”

“…TF antigens are defined as epitopes which are present on human erythrocytes after removal of surface sialic acid. They can be detected by antisera, monoclonal anti bodies (Mab) or peanut agglutinin [1,[3][4][5][6], Several lines of evidence suggest that the expression of TF antigens might have a role in organotropic metastasis of tumor cells into the liver. Most of the TF antigens carry terminal galactose residues and are, there fore, believed to interact with the asialogly coprotein receptor of the liver [7] as shown for lymphocytes and erythrocytes which ac cumulate in the liver after neuraminidase (NDA) treatment [8], Another example is the selective adherence of a highly metastatic variant of a mouse lymphoma cell line to syngeneic hepatocytes in contrast to its poorly metastatic parental line [9], The elu cidation of antigenic structures associated with metastasis is of clinical importance, be cause the intensity of the antigen on the tumor cells or the number of cells in the sur gically removed primary tumor expressing the antigen might correlate with the biologi cal behavior of tumor cells and might, final ly, lead to a better estimate of prognosis for the patients.…”

Isolation and Characterization of Thomsen-Friedenreich-Specific Antibodies from Human Serum

“…The presence of such autoantibodies against GP (as well as antibodies directed against peptide epitopes unmasked by desialylation of GP) in human sera has to our knowledge not yet been described in the literature. It has to be considered if aGP is used as an immunosorbent for the isolation of anti-TF antibodies, as has been done in previous publications [15,19,20,22,23], and it underscores the advantage of the immunosorbent used in our study.…”

“…This method was also used by Wolf et al [20]. They obtained two fractions with different specificities, in which the hemagglutination by one of them was not inhibited by the TF disaccharide.…”

Bridging Innate and Adaptive Antitumor Immunity Targeting Glycans

“…Two TACAs that are highly thought of as immune targets are the Thomsen-Friedenreich (TF or T) antigen (Galb1-3GalNAca) and the Tn (GalNAca) antigens [60]. Human blood serum contains natural TF- and Tn antibodies whose subpopulations may bind the corresponding antigens on human tumor cell lines [61, 62]. The high level of anti-TF and Tn IgG, observed in some patients with cancer, may be a sign of an ongoing immune response, as indicated by the switching of antibody to the IgG-class.…”