Characterization of T cell hybridomas raised against a glycopeptide containing the tumor-associated T antigen, (βGal (1–3) αGalNAc-O/Ser)

T cell hybridomas were raised against the glycopeptide S 72 (Core-1) containing the tumor-associated disaccharide βGal (1–3) αGalNAc (Core-1) O -linked to serine at position 72 in the mouse hemoglobin derived decapeptide Hb (67–76). All hybridomas recognized the glycopeptide S 72 (Core-1). Two of the selected hybridomas responded, however, much better to the S 72 (Tn) glycopeptide containing the monosaccharide αGalNAc O -linked to serine. In addition, one hybridoma cross-responded to the glycopeptide T 72 (Core-1) having a threonine at position 72 instead of a serine. No cross-responses were found to other glycopeptides consisting of the same hemoglobin peptide with different glycans attached or to the unglycosylated peptides. The T cell receptor Vα and Vβ usage was clearly diverse. The CDR3α regions demonstrated moreover a predominance of small polar amino acid side chains, and three hybridomas contained a common sequence motif. All the sequenced CDR3β regions contained furthermore a conserved proline-glycine motif. In conclusion, immunization with the disaccharide containing glycopeptides S 72 (Core-1) created a heterogeneous population of glycopeptide specific T cells with the ability of cross-responding toward related glycopeptides.