In vitro induction of specific CD8 ⁺ T lymphocytes by tumor-associated antigenic peptides in patients with oral squamous cell carcinoma

The aim of this study was to clarify candidate peptides for peptide-based specific immunotherapy of patients with oral squamous cell carcinoma (SCC). Thirteen peptides were examined for in vitro induction of peptide-specific CD8 ⁺ T lymphocyte (CD8 ⁺TL) activity in peripheral blood mononuclear cells from 35 patients with oral SCC. A correlation between the induction ability of CD8 ⁺TL and in vivo immune response of host was carried out immunohistochemically in 23 patients. Peptide-specific activities of CD8 ⁺TL for at least one peptide were detectable in 21/35 patients (60.0%). The potent peptides were SART-1 ₆₉₀ in 9/35 (25.7%), SART-2 ₉₃, and ART4 ₇₅ in 7/35 (20.0%), respectively. In the 9 patients with SART-1 ₆₉₀-specific activity, the whole of activities was significantly inducible for more number of other peptides compared to that in 26 patients without the activity (P=0.035). Cellular responses in 7 patients with SART-1 ₆₉₀-specific activity were significantly stronger than those in 16 patients without the activity (P=0.027). Furthermore, the number of CD3 ⁺ T cells around the SCC was also significantly different between the 2 groups of patients (P=0.041). In conclusion, SART-1 ₆₉₀, SART-2 ₉₃, and ART4 ₇₅ could be applicable as peptide-based specific immunotherapies for the majority of patients with oral SCC.