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Adoptive transfer of tumor infiltrating lymphocytes (TIL therapy) has proven highly effective for treating solid cancers, including non-small cell lung cancer (NSCLC). However, not all patients benefit from this therapy for yet unknown reasons. Defining markers that correlate with high tumor-reactivity of the autologous TIL products is thus key for achieving better tailored immunotherapies. We questioned whether the composition of immune cell infiltrates correlated with the tumor-reactivity of expanded TIL products. Unbiased flow cytometry analysis of immune cell infiltrates of 26 early-stage and 20 late-stage NSCLC tumor lesions was used for correlations with the T cell differentiation and activation status, and with the expansion rate and anti-tumor response of generated TIL products. The composition of tumor immune infiltrates was highly variable between patients. Spearman's Rank Correlation revealed that high B cell infiltration negatively correlated with the tumor-reactivity of the patient's expanded TIL products, as defined by cytokine production upon exposure to autologous tumor digest. In-depth analysis revealed that tumor lesions with high B cell infiltrates contained tertiary lymphoid structure (TLS)-related immune infiltrates, including BCL6+ antibody-secreting B cells, IgD+BCL6+ B cells and CXCR5+BLC6+ CD4+ T cells, and higher percentages of naïve CD8+ T cells. In conclusion, the composition of immune cell infiltrates in NSCLC tumors associates with the functionality of the expanded TIL product. Our findings may thus help improve patient selection for TIL therapy. [ABSTRACT FROM AUTHOR]

CD8+ T cells kill target cells by releasing cytotoxic molecules and proinflammatory cytokines, such as TNF and IFN‐γ. The magnitude and duration of cytokine production are defined by posttranscriptional regulation, and critical regulator herein are RNA‐binding proteins (RBPs). Although the functional importance of RBPs in regulating cytokine production is established, the kinetics and mode of action through which RBPs control cytokine production are not well understood. Previously, we showed that the RBP ZFP36L2 blocks the translation of preformed cytokine encoding mRNA in quiescent memory T cells. Here, we uncover that ZFP36L2 regulates cytokine production in a time‐dependent manner. T cell‐specific deletion of ZFP36L2 (CD4‐cre) had no effect on T‐cell development or cytokine production during early time points (2–6 h) of T‐cell activation. In contrast, ZFP36L2 specifically dampened the production of IFN‐γ during prolonged T‐cell activation (20–48 h). ZFP36L2 deficiency also resulted in increased production of IFN‐γ production in tumor‐infiltrating T cells that are chronically exposed to antigens. Mechanistically, ZFP36L2 regulates IFN‐γ production at late time points of activation by destabilizing Ifng mRNA in an AU‐rich element‐dependent manner. Together, our results reveal that ZFP36L2 employs different regulatory nodules in effector and memory T cells to regulate cytokine production. [ABSTRACT FROM AUTHOR]

T cells are key players in our defence against infections and malignancies. When T cells differentiate or become activated, they undergo substantial alterations in gene expression. Even though RNA expression levels are now well documented throughout different stages of T cells, it is not well understood how mRNA expression translates into the protein landscape. By combining paired RNA sequencing and mass spectrometry data of primary human CD8+ T cells, we report that mRNA expression is a poor proxy for the overall protein output, irrespective of the differentiation or activation status. Yet, gene class stratification revealed a function-specific correlation of mRNA with protein expression. This gene class-specific expression pattern associated with differences in gene characteristics such as sequence conservation and untranslated region (UTR) lengths. In addition, the presence of AU-rich elements in the 3'UTR associated with alterations in mRNA and protein abundance T cell activation dependent, gene class-specific manner. In conclusion, our study highlights the role of gene characteristics as a determinant for gene expression in T cells. [ABSTRACT FROM AUTHOR]