Invariant NKT cells are resistant to circulating CD15+ myeloid-derived suppressor cells in patients with head and neck cancer.
Bottom Line: However, the effect on the host immune system, especially on invariant NKT (iNKT) cells with potent anti-tumor activity, remains unclear.However, iNKT cell activation upon α-galactosylceramide (αGalCer) stimulation was not affected by the presence or absence of CD15+ G-MDSC.Cancer immunotherapy designed to enhance the antitumor activity of iNKT cells by stimulation with αGalCer may remain effective in the presence of G-MDSC.
Affiliation: Department of Otorhinolaryngology, Head and Neck Surgery, Graduate School of Medicine, Chiba University, Chiba, Japan.Show MeSH
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Mentions: We evaluated the proliferation and viability of iNKT cells and IFN‐γ production following stimulation with αGalCer in the presence or absence of CD15+ cells. In a representative HNSCC patient, the CD15+ cells comprised 15.8% of the HLA‐DR− Lin− fraction in PBC, and after CD15+ cell depletion, only 0.01% were positive (Fig. 6a). There was no significant difference in the cell number (Fig. 6b), the ratio in PBC (Fig. 6c) and the cell death in iNKT cells (Fig. 6d,e) between CD15+ cell replete cultures and CD15+ cell‐depleted cultures after 5 days. There was no significant difference in the IFN‐γ production of iNKT cells between non‐depleted and CD15+ cell‐depleted cultures after 5 days (Fig. 6f). Similarly, 5 days after stimulation with αGalCer, there was no difference in iNKT cell number between CD15+ cell‐depleted and CD15+ cell‐added PBC (Fig. 5f). These results were repeated in three samples.
Affiliation: Department of Otorhinolaryngology, Head and Neck Surgery, Graduate School of Medicine, Chiba University, Chiba, Japan.