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The Ikaros family transcription factor Aiolos is important for B cell function, since B cells of Aiolos-null mutant mice exhibit an activated phenotype, enhanced B-cell receptor (BCR) signalling response and develop a systemic lupus erythematosus (SLE) type autoimmune disease. Aiolos has also been reported to interact with anti-apoptotic Bcl-2 and Bcl-xL in T cells, but whether Aiolos regulates cell death has not been studied in B cells. Here we show that the disruption of Aiolos in the DT40 B cell line induces a cell death sensitive phenotype, as the Aiolos−/− cells are more prone to apoptosis by nutritional stress, BCR cross-linking, UV- or γ-irradiation. Furthermore, the Aiolos−/− cells have defective Ig gene conversion providing evidence that Aiolos is needed for the somatic diversification of the BCR repertoire. The re-expression of DNA-binding isoform Aio-1 was able to restore the gene conversion defect of the Aiolos-deficient cells, whereas the introduction of dominant negative isofom Aio-2 had no effect on gene conversion, thus demonstrating the functional importance of alternative splicing within Ikaros family. Although the Aiolos−/− cells exhibit reduced expression of activation-induced cytidine deaminase (AID), ectopic AID overexpression did not restore the gene conversion defect in the Aiolos−/− cells. Our findings indicate that Aiolos may regulate gene conversion in an AID independent manner. [ABSTRACT FROM AUTHOR]

Despite immunotherapy's promise in cancer treatment, patient responses vary substantially because of the individual nature of the immune system and the lack of reliable biomarkers. To address this issue, we developed a precision ex vivo platform that integrates patient-specific tumor and immune cells to study the mechanisms of antitumor immune response, predict immunotherapy outcomes, and identify effective treatments. This platform revealed unique single-cell immune response mechanisms and sensitivities to standard-of-care immunotherapies. Furthermore, we were able to identify a synergistic combination of anti-programmed cell death protein 1 (anti-PD-1) together with a Casitas B lineage lymphoma-b inhibitor that overcame anti-PD-1 resistance in selected patient samples. Activation of the interferon-1-stimulated cytokines predicted combination efficacy, while immunosuppressive cytokines were associated with poor response. Our findings underscore the platform's potential in tailoring immunotherapies and advancing drug development, offering avenues for personalized cancer treatment. [ABSTRACT FROM AUTHOR]