Chimeric antigen receptor (CAR)-T cell therapy holds significant potential for the treatment of solid tumors. However, immune suppression and tumor-specific barriers limit its application. Claudin 18.2 (CLDN18.2), a gastric lineage-specific tight junction protein highly expressed in gastric and pancreatic cancers, is a promising therapeutic target. In this study, we aimed to develop a next-generation tri-cistronic CLDN18.2-directed CAR-T cell platform that integrates a programmed cell death protein 1 (PD-1)/CD28 chimeric switch receptor with cyclophilin A (CypA). This platform sought to counteract PD-1–mediated immunosuppression and enhance T-cell activation and persistence. We generated CLDN18.2 CAR-T cells incorporating costimulatory inducible T-cell costimulator (ICOS) domains using lentiviral vector-based recombinant engineering. We further evaluated their cytokine release, cytotoxic activity, and safety profiles. In vitro, tri-cistronic CAR-T cells exhibited markedly increased interferon γ and tumor necrosis factor α secretion and enhanced cytotoxicity against CLDN18.2-positive gastric cancer cells compared with conventional CAR-T constructs. In vivo, these cells showed superior antitumor efficacy and sustained tumor regression without observable toxicity in xenograft gastric cancer models. Collectively, these findings demonstrate that the integration of PD-1/CD28 signaling and CypA within a tri-cistronic framework significantly reinforces CAR-T cell functionality and durability. This suggests strong clinical potential as a next-generation immunotherapy for solid tumors.
The widespread use of antibiotics in aquaculture has led to the emergence of multidrug-resistant pathogens and environmental concerns, highlighting the need for sustainable, eco-friendly alternatives. In this study, we isolated and characterized three novel bacteriophages from aquaculture effluents in Korean shrimp farms that target the key Vibrio pathogens, Vibrio harveyi, and Vibrio parahaemolyticus. Bacteriophages were isolated through environmental enrichment and serial purification using double-layer agar assays. Transmission electron microscopy revealed that the phages infecting V. harveyi, designated as vB_VhaS-MS01 and vB_VhaS-MS03, exhibited typical Siphoviridae morphology with long contractile tails and icosahedral heads, whereas the phage isolated from V. parahaemolyticus (vB_VpaP-MS02) displayed Podoviridae characteristics with an icosahedral head and short tail.
Whole-genome sequencing produced complete, circularized genomes of 81,710 bp for vB_VhaS-MS01, 81,874 bp for vB_VhaS-MS03, and 76,865 bp for vB_VpaP-MS02, each showing a modular genome organization typical of Caudoviricetes. Genomic and phylogenetic analyses based on the terminase large subunit gene revealed that although vB_VhaS-MS01 and vB_VhaS-MS03 were closely related, vB_VpaP-MS02 exhibited a distinct genomic architecture that reflects its unique morphology and host specificity. Collectively, these comparative analyses demonstrated that all three phages possess genetic sequences markedly different from those of previously reported bacteriophages, thereby establishing their novelty. One-step growth and multiplicity of infection (MOI) experiments demonstrated significant differences in replication kinetics, such as burst size and lytic efficiency, among the phages, with vB_VhaS-MS03 maintaining the most effective bacterial control, even at an MOI of 0.01. Additionally, host range assays showed that vB_VhaS-MS03 possessed a broader spectrum of activity, supporting its potential use as a stand-alone agent or key component of phage cocktails. These findings highlight the potential of region-specific phage therapy as a targeted and sustainable alternative to antibiotics for controlling Vibrio infections in aquaculture.
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