ObjectiveTo optimize the flow cytometric sorting workflow for myeloid-derived suppressor cells （MDSCs） from murine Lewis lung carcinoma （LLC） subcutaneous tumor tissues， improving single-cell suspension preparation efficiency and sorting purity， thereby providing high-quality cells for subsequent functional studies. MethodsSubcutaneous LLC tumor tissues were harvested from C57BL/6 mice， and two enzymatic digestion protocols were first compared to evaluate their effects on single-cell suspension preparation. After staining with a viability dye （Live/Dead） and fluorochrome-conjugated anti-mouse antibodies against CD45， CD11b， and Gr-1， cells were loaded onto a Beckman CytoFLEX cell sorter. Next， conventional and optimized gating strategies were applied. In the optimized strategy， the CD45⁺ population was used as the initial gate to directly define an MDSC-enriched region， followed by selection of CD11b⁺Gr-1⁺ cells. Finally， purity was assessed by flow cytometry， viability was determined by trypan blue staining， and RT-qPCR was performed to measure the expression of MDSC signature genes， including Arg1， Nos2， IL-10， and S100A8/A9. ResultsThe optimized enzymatic digestion protocol significantly increased the yield and viability of single cells. After optimization of the gating strategy， the post-sort positivity rate （purity） was markedly improved. Arg1， Nos2， IL-10 and S100A8/A9 were highly expressed in the sorted cells， indicating that the isolated cells retained characteristic MDSC features and functional signatures. ConclusionBy optimizing both the tissue digestion protocol and the flow cytometric gating strategy， we establish an efficient workflow for isolating MDSCs from tumor tissues. This method improves the yield and purity of single-cell preparations while preserving antigen integrity， providing a reliable methodological foundation for subsequent studies on MDSC function and metabolism.

Drug-induced liver injury(DILI)is one of the major challenges in drug development and clinical practice,and effective prevention and con-trol measures remain lacking.Research has shown that DILI is primarily mediated by immune respons-es.Human leukocyte antigen(HLA)alleles are cur-rently the strongest genetic factors reported to be associated with DILI.Due to the low positive predic-tive value of HLA alleles,preemptive HLA genetic screening has limited clinical utility in preventing DILI.However,its high negative predictive value makes it valuable for DILI diagnosis and causality assessment.In recent years,polymorphisms in im-mune-related genes-such as those involved in anti-gen processing and presentation pathways,T-cell receptors,immunostimulatory molecules,and cyto-kines-have been found to be associated with DILI.Future studies combining these genes with HLA analysis may provide deeper mechanistic insights into DILI and facilitate their translational applica-tion in clinical practice,ultimately improving drug safety.

Drug-induced liver injury(DILI)is one of the major challenges in drug development and clinical practice,and effective prevention and con-trol measures remain lacking.Research has shown that DILI is primarily mediated by immune respons-es.Human leukocyte antigen(HLA)alleles are cur-rently the strongest genetic factors reported to be associated with DILI.Due to the low positive predic-tive value of HLA alleles,preemptive HLA genetic screening has limited clinical utility in preventing DILI.However,its high negative predictive value makes it valuable for DILI diagnosis and causality assessment.In recent years,polymorphisms in im-mune-related genes-such as those involved in anti-gen processing and presentation pathways,T-cell receptors,immunostimulatory molecules,and cyto-kines-have been found to be associated with DILI.Future studies combining these genes with HLA analysis may provide deeper mechanistic insights into DILI and facilitate their translational applica-tion in clinical practice,ultimately improving drug safety.