Aberrant expression of programmed death ligand 1 (PD-L1) on tumor cells impedes antitumor immunity and instigates immune evasion. The remarkable efficacy of immune checkpoint blockade has been confirmed in various solid tumors. However, the correlation between PD-L1 expression and host immunological landscape remains of considerable controversy in non-small cell lung cancer (NSCLC). In the present study, PD-L1 expression and CD8+ tumor-infiltrating lymphocyte (TIL) infiltration levels were determined by immunohistochemistry (IHC) in tumor sections of 138 NSCLC patients. The expression level of PD-L1 was positively correlated with the abundance of CD8 + TILs (p < 0.0001). Furthermore, no constitutive expression of PD-L1 was observed in the majority of six NSCLC cell lines detected by Western blot; but exposure to interferon-γ (IFN-γ), a primary cytokine secreted by activated CD8+ T cells, prominently increased PD-L1 expression. Notably, a significantly positive association was determined within PD-L1, CD8 and IFN-γ gene expression by qRT-PCR, which was corroborated by RNA-sequencing from TCGA lung cancer dataset. These findings demonstrate that PD-L1 expression indicates an adaptive immune resistance mechanism adopted by tumor cells in the aversion of immunogenic destruction by CD8+ TILs. Both higher expression of PD-L1 and infiltration of CD8+ TILs were correlated with superior prognosis (p = 0.044 for PD-L1; p = 0.002 for CD8). Moreover, Cox multivariate regression analysis showed that the combination of PD-L1 and CD8 were independent prognostic factors, which was more accurate in prediction of prognosis in NSCLC than individually. Finally, we found that IFN-γ induced the upregulation of PD-L1 in NSCLC cells, mainly through the JAK/STAT1 signaling pathway. In conclusion, PD-L1 expression is mainly induced by activated CD8+ TILs via IFN-γ in the immune milieu and indicates pre-existing adaptive immune response in NSCLC.

Methicillin-resistant Staphylococcus aureus (MRSA) has become an important nosocomial pathogen, causing considerable morbidity and mortality. During the last 20 years, a variety of genotyping methods have been introduced for screening the prevalence of MRSA. In this study, we developed and evaluated an improved approach capillary gel electrophoresis based multilocus variable-number tandem-repeat fingerprinting (CGE/MLVF) for rapid MRSA typing. A total of 42 well-characterized strains and 116 non-repetitive clinical MRSA isolates collected from six hospitals in northeast China between 2009 and 2010 were tested. The results obtained by CGE/MLVF against clinical isolates were compared with traditional MLVF, spa typing, Multilocus sequence typing/ staphylococcal cassette chromosome mec (MLST/SCCmec) and pulse field gel electrophoresis (PFGE). The discriminatory power estimated by Simpson's index of diversity was 0.855 (28 types), 0.855 (28 patterns), 0.623 (11 types), 0.517 (8 types) and 0.854 (28 patterns) for CGE/MLVF, traditional MLVF, spa typing, MLST/SCCmec and PFGE, respectively. All methods tested showed a satisfied concordance in clonal complex level calculated by adjusted Rand's coefficient. CGE/MLVF showed better reproducibility and accuracy than traditional MLVF and PFGE methods. In addition, the CGE/MLVF has potential to produce portable results. In conclusion, CGE/MLVF is a rapid and easy to use MRSA typing method with lower cost, good reproducibility and high discriminatory power for monitoring the outbreak and clonal spread of MRSA isolates.

Blockade of the immunosuppressive checkpoint receptors cytotoxic T-lymphocyte-associated protein 4 (CTLA4) or programmed death 1 (PD-1) and its cognate ligand, programmed death 1 ligand (PD-L1), has altered the landscape of anti-tumor immunotherapy. B7 family and tumor necrosis factor receptor (TNFR) superfamily play a crucial role in T cell activation, tolerance, and anergy through co-stimulatory and inhibitory signal transduction. Investigating the immune molecular landscapes of the B7 and TNFR families is critical in defining the promising responsive candidates. Herein, we performed comprehensive alteration analysis of the B7 and TNFR family genes across six hepatocellular carcinoma (HCC) datasets with over 1000 patients using cBioPortal TCGA data. About 16% of patients had both B7 and TNFR gene alterations. TNFR gene amplifications were relatively more common (1.73⁻8.82%) than B7 gene amplifications (1.61⁻2.94%). Analysis of 371 sequenced samples revealed that all genes were upregulated: B7 and TNFR mRNA were upregulated in 23% of cases (86/371) and 28% of cases (105/371), respectively. Promoter methylation analysis indicated an epigenetic basis for B7 and TNFR gene regulation. The mRNA levels of B7 and TNFR genes were inversely correlated with promoter methylation status. B7-H6 expression was significantly associated with worse overall survival, and B7-H6 mRNA was increased gradually in cases with gene copy number alterations. B7-H6 overexpression was associated with aggressive clinicopathologic features and poor prognosis in HCC. Downregulation of B7-H6 in HCC cells significantly inhibited cell adhesion, proliferation, migration, and invasion. Knockdown of B7-H6 in HCC cells inhibited tumor growth and metastasis in vivo. B7-H6 promoted HCC metastasis via induction of MMP-9 expression and STAT3 activation. B7-H6 and STAT3 performed functional overlapping roles on enhancing the MMP-9 promoter activity in HCC cells. These results suggest that alterations of the immunologic co-stimulator B7 and TNFR families correlate with HCC metastasis and prognosis, and especially B7-H6 plays a critical role in promoting metastasis of HCC.

Wilms tumor 1 (WT1) oncoprotein is an intracellular oncogenic transcription factor which is barely expressed in normal adult tissues but over expressed in a variety of leukemias and solid cancers. WT1-derived HLA-A*02:01 T cell epitope, RMFPNAPYL (RMF), is a validated target for T cell-based immunotherapy. We generated two T cell receptor mimic antibody-drug conjugates (TCRm-ADCs), ESK-MMAE, and Q2L-MMAE, against WT1 RMF/HLA-A*02:01 complex with distinct affinities, which mediate specific antitumor activity. Although ESK-MMAE showed higher tumor growth inhibition ratio in vivo, the efficacy of them was not so promising, which might be due to low expression of peptide/HLA targets. Therefore, we explored a bispecific TCRm-ADC that exerted more potent tumor cytotoxicity compared with TCRm-ADCs. Hence, our findings validate the feasibility of the presenting intracellular peptides as the targets of ADCs, which broadens the antigen selection range of antibody-based drugs and provides new strategies for precision medicine in tumor therapy.