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Natural Killer (NK) cell dysfunction is associated with poorer clinical outcome in cancer patients. What regulates NK cell dysfunction in tumor microenvironment is not well understood. Here, we demonstrate that the human tumor-derived NKG2D ligand soluble MIC (sMIC) reprograms NK cell to secrete pro-tumorigenic cytokines with diminished cytotoxicity and polyfunctional potential. Antibody clearing sMIC restores NK cell to a normal cytotoxic effector functional state. We discovered that sMIC selectively activates the CBM-signalosome inflammatory pathways in NK cells. Conversely, tumor cell membrane-bound MIC (mMIC) stimulates NK cell cytotoxicity through activating PLC2γ2/SLP-76/Vav1 pathway. Ultimately, antibody targeting sMIC effectuated the in vivo anti-tumor effect of adoptively transferred NK cells. Our findings uncover an unrecognized mechanism that could instruct NK cell to a dysfunctional state in response to cues in the tumor microenvironment. Our findings provide a rationale for co-targeting sMIC to enhance the efficacy of the ongoing NK cell-based cancer immunotherapy. Dhar et al used primary human and mouse natural killer (NK) cells to demonstrate that tumor-derived NKG2D ligand soluble MIC (sMIC) can reprogram the NK cells to secrete pro-tumorigenic cytokines with diminished cytotoxicity and polyfunctional potential. Their study provides a rationale for co-targeting sMIC in order to enhance current NK cell-based cancer immunotherapies. [ABSTRACT FROM AUTHOR]

SARS-CoV-2 emerged as a worldwide pandemic in late 2019 and initially was described as a primary respiratory illness. The clinical manifestations of COVID-19 are now known to encompass nearly all organ systems, including the central nervous system. We present a case of an allogeneic hematopoietic stem cell transplant recipient who recovered from documented SARS-CoV-2 infection and later presented with symptoms of meningitis. While cerebrospinal fluid analysis did not reveal any bacterial or viral etiologies, evidence of an inflammatory state, including ophthalmologic findings of episcleritis, indicate what is likely the first reported case of aseptic meningitis associated with SARS-CoV-2 infection after initial clinical recovery. [ABSTRACT FROM AUTHOR]

SARS-CoV-2 emerged as a worldwide pandemic in late 2019 and initially was described as a primary respiratory illness. The clinical manifestations of COVID-19 are now known to encompass nearly all organ systems, including the central nervous system. We present a case of an allogeneic hematopoietic stem cell transplant recipient who recovered from documented SARS-CoV-2 infection and later presented with symptoms of meningitis. While cerebrospinal fluid analysis did not reveal any bacterial or viral etiologies, evidence of an inflammatory state, including ophthalmologic findings of episcleritis, indicate what is likely the first reported case of aseptic meningitis associated with SARS-CoV-2 infection after initial clinical recovery. [ABSTRACT FROM AUTHOR]

Background: Melanoma patients who have detectable serum soluble NKG2D ligands either at the baseline or post-treatment of PD1/PDL1 blockade exhibit poor overall survival. Among families of soluble human NKG2D ligands, the soluble human MHC I chain-related molecule (sMIC) was found to be elevated in melanoma patients and mostly associated with poor response to PD1/PDL1 blockade therapy. Methods: In this study, we aim to investigate whether co-targeting tumor-released sMIC enhances the therapeutic outcome of PD1/PDL1 blockade therapy for melanoma. We implanted sMIC-expressing B16F10 melanoma tumors into syngeneic host and evaluated therapeutic efficacy of anti-sMIC antibody and anti-PDL1 antibody combination therapy in comparison with monotherapy. We analyzed associated effector mechanism. We also assessed sMIC/MIC prevalence in metastatic human melanoma tumors. Results: We found that the combination therapy of the anti-PDL1 antibody with an antibody targeting sMIC significantly improved animal survival as compared to monotherapies and that the effect of combination therapy depends significantly on NK cells. We show that combination therapy significantly increased IL-2Rα (CD25) on NK cells which sensitizes NK cells to low dose IL-2 for survival. We demonstrate that sMIC negatively reprograms gene expression related to NK cell homeostatic survival and proliferation and that antibody clearing sMIC reverses the effect of sMIC and reprograms NK cell for survival. We further show that sMIC/MIC is abundantly present in metastatic human melanoma tumors. Conclusions: Our findings provide a pre-clinical proof-of-concept and a new mechanistic understanding to underscore the significance of antibody targeting sMIC to improve therapeutic efficacy of anti-PD1/PDL1 antibody for MIC/sMIC+ metastatic melanoma patients. [ABSTRACT FROM AUTHOR]

The ETS factor Friend leukemia virus integration 1 (FLI1) is a key modulator of lupus disease expression. Overexpressing FLI1 in healthy mice results in the development of an autoimmune kidney disease similar to that observed in lupus. Lowering the global levels of FLI1 in two lupus strains (Fli1+/-) significantly improved kidney disease and prolonged survival. T cells from MRL/lpr Fli1+/- lupus mice have reduced activation and IL-4 production, neuraminidase 1 expression, and the levels of the glycosphingolipid lactosylceramide. In this study, we demonstrate that MRL/lpr Fli1+/- mice have significantly decreased renal neuraminidase 1 and lactosylceramide levels. This corresponds with a significant decrease in the number of total CD3+ cells, as well as CD4+ and CD44+CD62L- T cell subsets in the kidney of MRL/lpr Fli1+/- mice compared with the Fli1+/+ nephritic mice. We further demonstrate that the percentage of CXCR3+ T cells and Cxcr3 message levels in T cells are significantly decreased and correspond with a decrease in renal CXCR3+ cells and in Cxcl9 and Cxcl10 expression in the MRL/lpr Fli1+/- compared with the Fli1+/+ nephritic mice. Our results suggest that reducing the levels of FLI1 in MRL/lpr mice may be protective against development of nephritis in part through downregulation of CXCR3, reducing renal T cell infiltration and glycosphingolipid levels. [ABSTRACT FROM AUTHOR]

Systemic Lupus erythematosus (SLE) is an autoimmune disease caused, in part, by abnormalities in cells of the immune system including B and T cells. Genetically reducing globally the expression of the ETS transcription factor FLI1 by 50% in two lupus mouse models significantly improves disease measures and survival through an unknown mechanism. In this study we analyze the effects of reducing FLI1 in the MRL/lpr lupus prone model on T cell function. We demonstrate that adoptive transfer of MRL/lpr Fli1+/+ or Fli1+/- T cells and B cells into Rag1-deficient mice results in significantly decreased serum immunoglobulin levels in animals receiving Fli1+/- lupus T cells compared to animals receiving Fli1+/+ lupus T cells regardless of the genotype of co-transferred lupus B cells. Ex vivo analyses of MRL/lpr T cells demonstrated that Fli1+/- T cells produce significantly less IL-4 during early and late disease and exhibited significantly decreased TCR-specific activation during early disease compared to Fli1+/+ T cells. Moreover, the Fli1+/- T cells expressed significantly less neuraminidase 1 (Neu1) message and decreased NEU activity during early disease and significantly decreased levels of glycosphingolipids during late disease compared to Fli1+/+ T cells. FLI1 dose-dependently activated the Neu1 promoter in mouse and human T cell lines. Together, our results suggest reducing FLI1 in lupus decreases the pathogenicity of T cells by decreasing TCR-specific activation and IL-4 production in part through the modulation of glycosphingolipid metabolism. Reducing the expression of FLI1 or targeting the glycosphingolipid metabolic pathway in lupus may serve as a therapeutic approach to treating lupus. [ABSTRACT FROM AUTHOR]