Differential dendritic cell‐mediated activation and functions of invariant NKT ‐cell subsets in oral cancer

Objectives Invariant natural killer T (i NKT ) cells are unique subset of glycolipid‐reactive T lymphocytes with potent antitumour characteristics. This study was planned to understand Th‐like cytokine profiles of i NKT ‐cell subsets and modulation of their functions in response to glycolipid ligand and tumour cell lysate ( TL ). Subjects and Methods Cytokine profile of iNKT ‐cell subsets was evaluated from the peripheral blood of eight oral squamous cell carcinoma ( OSCC ) patients by flow cytometry and enzyme‐linked immunosorbent assay ( ELISA ), while antitumour activity of iNKT cells was measured by methyl tetrazolium salt assay. Results CD 4 + ( CD 4 + CD 8 − ) iNKT subset from OSCC patients showed significant ( P  < 0.01) expansion and higher IL‐4 production following activation with α ‐GalCer‐pulsed DC s, while CD 4 − CD 8 − double negative ( DN ) and CD 8 + ( CD 4 − CD 8 + ) i NKT subsets produced IFN ‐ γ predominantly. i NKT cells showed significantly ( P  = 0.02) increased secretion of IFN ‐ γ and enhanced cytotoxicity to KB and SCC ‐4 tumour cells in response to α ‐GalCer and TL ‐pulsed DC s. Conclusion It appears that mutual balance/ratio of i NKT subsets may be important for their effector functions. Selectively expanded DN and CD 8 + i NKT cells with α ‐GalCer and TL may be a better candidate vaccine for i NKT ‐cell‐based adoptive cancer immunotherapy.