Metabolic disorders mediated chimeric antigen receptor - T cell (CAR-T) exhaustion impaired cancer immunotherapy. Endogenous sulfur dioxide (SO₂) derived from L-cysteine catalysis regulated immune cell functions. However, its role in CAR-T cell exhaustion remained unknown. In this study, we identified that SO₂ accumulated in the bone marrow microenvironment of relapsed multiple myeloma patients inhibited CD8⁺ T cell and CAR-T cell infiltration and promoted a transcriptional profile consistent with functional exhaustion, leading to impaired antitumor immunity. Tumor cell derived SO₂ altered mitochondrial morphology and disrupted mitochondrial membrane potential in CAR-T cells, accompanied by impaired cytokine secretion and loss of cytotoxic function. Mechanistically, SO₂ enhanced interaction of dynamin-related protein 1 (DRP1) and voltage-dependent anion channel 1 and mitochondrial fission via DRP1 sulphenylation at cysteine 607 (Cys607), with abnormal increases in DRP1 GTPase activity, disrupting mitochondrial integrity. Site mutation of Cys607 in CAR-T cells abrogated DRP1 sulphenylation and restored mitochondrial structure and improves antitumor immunity. These findings define a novel redox-mediated mechanism of mitochondrial dysfunction in CAR-T cells exhaustion and identify the SO₂-DRP1 axis as a potential therapeutic target to overcome metabolic exhaustion in CAR-T cell therapy.

Porcine epidemic diarrhea virus (PEDV) and porcine deltacoronavirus (PDCoV) cause severe diarrhoea in piglets, requiring rapid laboratory differentiation. In this technical note, we evaluated primer–probe sets from Chinese quarantine industry standards on the Coyote Flash10 cartridge-based POCT combined primer–probe RT qPCR platform. Assays were characterised using a digitally PCR-quantified single-target in vitro transcribed viral RNA and RNA-spiked porcine faecal matrix. Exploratory low-concentration amplifications were observed at 3.222 copies/μL (PEDV) and 2.28 copies/μL (PDCoV); however, the corresponding Ct values fell within an indeterminate range, and no statistically validated limits of detection were established. The PEDV standard curve included concentrations with mean Ct values in the indeterminate and negative ranges, so its apparent efficiency was not considered a validated performance metric. PDCoV efficiency was sub-optimal (~77.7%). Low intra run Ct variability (CV < 3%) was observed in spiked matrix tests. No cross amplification was detected against four selected swine pathogens under the tested conditions. Notably, mixed-ratio co-template viral RNA experiments simulating co-infection were not performed. The proprietary internal control (IC) was recorded descriptively and was not used to assess extraction efficiency or sample validity. This work demonstrates preliminary analytical feasibility of this primer–probe combination on the Flash10 platform; full clinical diagnostic performance remains to be validated in further studies.