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Only some cancer patients respond to the immune-checkpoint inhibitors being used in the clinic, and other therapeutic targets are sought. Here, we investigated the HLA-G/ILT2 checkpoint in clear-cell renal-cell carcinoma (ccRCC) patients and focused on tumor-infiltrating CD8 + T lymphocytes (TIL) expressing the HLA-G receptor ILT2. Using transcriptomics and flow cytometry, we characterized both peripheral blood and tumor-infiltrating CD8 + ILT2 + T cells from cancer patients as late-differentiated CD27 - CD28 - CD57 + cytotoxic effectors. We observed a clear dichotomy between CD8 + ILT2 + and CD8 + PD-1 + TIL subsets. These subsets, which were sometimes present at comparable frequencies in TIL populations, barely overlapped phenotypically and were distinguished by expression of exclusive sets of surface molecules that included checkpoint molecules and activating and inhibitory receptors. CD8 + ILT2 + TILs displayed a more mature phenotype and higher expression of cytotoxic molecules. In ex vivo functional experiments with both peripheral blood T cells and TILs, CD8 + ILT2 + T cells displayed significantly higher cytotoxicity and IFNγ production than their ILT2 - (peripheral blood mononuclear cells, PBMC) and PD-1 + (TILs) counterparts. HLA-G expression by target cells specifically inhibited CD8 + ILT2 + T-cell cytotoxicity, but not that of their CD8 + ILT2 - (PBMC) or CD8 + PD-1 + (TIL) counterparts, an effect counteracted by blocking the HLA-G/ILT2 interaction. CD8 + ILT2 + TILs may therefore constitute an untapped reservoir of fully differentiated cytotoxic T cells within the tumor microenvironment, independent of the PD1 + TILs targeted by immune therapies, and specifically inhibited by HLA-G. These results emphasize the potential of therapeutically targeting the HLA-G/ILT2 checkpoint in HLA-G + tumors, either concomitantly with anti-PD-1/PD-L1 or in cases of nonresponsiveness to anti-PD-1/PD-L1., (©2019 American Association for Cancer Research.)

Hepatitis B virus (HBV) is a major cause of liver disease and hepatocellular carcinoma. Chronic HBV infection is currently managed with either nucleoside/nucleotide-based or interferon-based therapies, but fails to clear infection in a substantial proportion of cases, and antiviral strategies targeting the early stages of infection are therefore required for the prevention of HBV infection. In this study, we examined some common phytochemicals and identified epigallocatechin-3-gallate (EGCG) as a new inhibitor of HBV entry. EGCG, a flavonoid present in green tea extract, belongs to the subclass of catechins. We demonstrated that EGCG at a concentration of 50μM inhibited HBV entry into immortalized human primary hepatocytes by more than 80%, whereas the other four catechins tested had much weaker inhibitory effects. DMSO-differentiated HuS-E/2 cells expressed sodium taurocholate cotransporting polypeptide (NTCP), which is a receptor for HBV. Application of EGCG during HBV inoculation markedly inhibited infection in both DMSO-differentiated HuS-E/2 cells and HA-NTCP-expressing Huh7 cells. Interestingly, EGCG induced clathrin-dependent endocytosis of NTCP from the plasma membrane followed by protein degradation. In addition, EGCG inhibited the clathrin-mediated endocytosis of transferrin. Treatment of cells with EGCG had no effect on HBV genome replication or virion secretion. Moreover, the characteristic of HBV virion and the expression of known HBV entry factors were unaltered by EGCG. Finally, the antiviral activity of EGCG on HBV entry was observed using four different genotypes, A to D. These results show that the green tea-derived molecule EGCG potently inhibits HBV entry and could be used in prevention of HBV reinfection., (Copyright © 2014 Elsevier B.V. All rights reserved.)