Expression of Tumor‐associated Glycoantigen, Sialyl Lewis(a), in Human Head and Neck Squamous Cell Carcinoma and Its Application to Tumor Immunotherapy

The glycoantigen sialyl Lewis(a) (sLe(a)) is widely expressed on a variety of gastrointestinal tumor cells. Here, we immunohistochemically demonstrated the expression of sLe(a) antigen in 54% (7 out of 13) of human head and neck squamous cell carcinoma (H‐NSCG) samples. Frequent expression of sLe(a) antigen was also demonstrated on a variety of H‐NSCC cell lines using flow cytometry. Both CD4(+) and CD8(+) T cells, which were activated with immobilized OKT3 monoclonal antibody plus inter‐leukin‐2, showed augmented cytotoxicity against sLe(a)‐positive H‐NSCC, including autologous tumor cells, on targeting with anti‐CD3 x anti‐sLe(a) bispccific antibody, suggesting that sLe(a) antigen is a good target molecule for bispecific antibody‐dependent adoptive tumor immunotherapy of human head and neck cancer.