Functional Change of Effector Tumor-Infiltrating CCR5CD38HLA-DRCD8 T Cells in Glioma Microenvironment.

Human glioma facilitates an impaired anti-tumor immunity response, including defects in circulation of T lymphocytes. The level of CD8 T-cell activation acts as an immune regulator associated with disease progression. However, little is known about the characteristics of peripheral and tumor-infiltrating CD8 T cells in patients with glioma. In this study, we examined the level of CD8 T-cell activation in a group of 143 patients with glioma and determined that peripheral CD3 T cells decreased in accordance with disease severity. The patients' peripheral CD8 T-cell populations were similar to that of healthy donors, and a small amount of CD8 tumor-infiltrating lymphocytes was identified in glioma tissues. An increase in activated CD8 T cells, characterized as CD38HLA-DR, and their association with disease progression were identified in the patients' peripheral blood and glioma, and shown to display enriched CCR5 and TNFR2 expression levels. examination of CD38HLA-DRCD8 T cells indicated that this subset of cells displayed stronger secretion of IFN-γ and IL-2 before and after a 6-h stimulation with phorbol 12-myristate 13-acetate (PMA) and ionomycin (ION) relative to healthy CD38HLA-DRCD8 T cells, indicating the functional feasibility of CD38HLA-DRCD8 T cells. Higher CCL5 protein and mRNA levels were identified in glioma tissues, which was consistent with the immunohistochemistry results revealing both CCL5 and CD38HLA-DRCD8 T cell expression. Patients' CCR5CD38HLA-DRCD8 T cells were further validated and shown to display increases in CD45RACCR7 and T-bet accompanied by substantial CD107-a, IFN-γ, and Granzyme B levels in response to glioma cells.