Fig. 9

Effects of Usp22 on T cell cytotoxicity. a T cell killing assay of B16-F10 transfected with Pd-l1-His plasmids and Usp22 siRNA. Lymphocytes were isolated from C57BL/6 mice. Lymphocytes were stimulated with 5 μg/ml Concanavalin A (conA) for 48 h before co-cultured with B16-F10 cells for another 48 h in the presence of 5 μg/ml conA. The supernatant was used for LDH release assay. Error bars represent SD (n = 4). **P < 0.01, *P < 0.05, Statistical differences were determined by two sided Student’s t-test. b Western blot analysis of B16-F10 cells illustrated in (a). c KM plotter analysis of the relation between USP22 gene expression and prognosis (OS) in lung cancer patients. d Representative immunohistochemical staining results for US22 and PD-L1 in human lung adenocarcinoma (ADC) and squamous cell carcinoma (SCC). Scale bar, 50 μm (e) Proposed modal of USP22-mediated PD-L1 regulation. On the one hand, USP22 directly removed PD-L1 ubiquitination; on the other hand, USP22 modulated CSN5 through deubiquitination and regulated PD-L1 ubiquitination through USP22-CSN5-PD-L1 axis