Objective:Chimeric antigen receptor T-cell(CAR-T)immunotherapy has made major breakthroughs in the treatment of blood tu-mors.However,current CAR-T therapies face several limitations:they require autologous cells,involve a lengthy and costly production pro-cess,and use lentiviral transduction that carry risk of insertional carcinogenesis due to random integration.Therefore,there is an urgent need to develop a universal cost-effective cancer immunotherapy method generating CAR-T cells for in vivo cancer immunotherapy.Meth-ods:This study successfully established an exosome-mediated,T-cell targeted delivery system,demonstrating both precise design and func-tional efficacy for biomedical applications.To optimize CAR-T cell generation the transfection dose was adjusted,and the kinetics of CAR-T cell percentage were recorded.The cytotoxicity of the resulting CAR-T cells was evaluated in vitro by calcein-AM release.To test the tumor-killing in vivo of engineered exosomes,human PBMCs were injected into NPG mice via the tail vein to establish humanized mice,followed by intravenous injection of tumor cells to induce cancer.Results:To overcome the limitations of conditional autologous CAR-T cells,we de-veloped a T cell-targeted exosome system capable of specifically targeting human CD3+,CD4+,and CD8+T cells.CAR-T production was dose-dependent,with transfection efficiency reaching upto 97.8%at 106 particles/cell.Both in vitro cytotoxicity assays and in vivo animal experi-ments demonstrated that exosome-incubated CAR-T cells effectively eliminated CD19-positive Raji cells,highlighting their specificity and therapeutic potential in antigen-directed applications.Conclusions:We successfully established a CD8-targeting exosome delivery system for CAR-T cell production capable of transforming CD8+T cells into functional CAR-T cells,which showed significant tumor-killing ability in vitro and in mice.Compared with the traditional lentiviral vector for the preparation of CAR-T cells in vitro,in vivo-reprogrammed CAR-T cells us-ing our CD8-targeted exosome delivery system,with higher transfection efficiency,shorter production period,lower cost,and eliminated the risk of insertion carcinogenesis.This strategy promises to bring a new era of universal CAR-T medicine,which can improve cancer immuno-therapy and may hold promise as a therapeutic platform to treat various diseases.

Objective:Chimeric antigen receptor T-cell(CAR-T)immunotherapy has made major breakthroughs in the treatment of blood tu-mors.However,current CAR-T therapies face several limitations:they require autologous cells,involve a lengthy and costly production pro-cess,and use lentiviral transduction that carry risk of insertional carcinogenesis due to random integration.Therefore,there is an urgent need to develop a universal cost-effective cancer immunotherapy method generating CAR-T cells for in vivo cancer immunotherapy.Meth-ods:This study successfully established an exosome-mediated,T-cell targeted delivery system,demonstrating both precise design and func-tional efficacy for biomedical applications.To optimize CAR-T cell generation the transfection dose was adjusted,and the kinetics of CAR-T cell percentage were recorded.The cytotoxicity of the resulting CAR-T cells was evaluated in vitro by calcein-AM release.To test the tumor-killing in vivo of engineered exosomes,human PBMCs were injected into NPG mice via the tail vein to establish humanized mice,followed by intravenous injection of tumor cells to induce cancer.Results:To overcome the limitations of conditional autologous CAR-T cells,we de-veloped a T cell-targeted exosome system capable of specifically targeting human CD3+,CD4+,and CD8+T cells.CAR-T production was dose-dependent,with transfection efficiency reaching upto 97.8%at 106 particles/cell.Both in vitro cytotoxicity assays and in vivo animal experi-ments demonstrated that exosome-incubated CAR-T cells effectively eliminated CD19-positive Raji cells,highlighting their specificity and therapeutic potential in antigen-directed applications.Conclusions:We successfully established a CD8-targeting exosome delivery system for CAR-T cell production capable of transforming CD8+T cells into functional CAR-T cells,which showed significant tumor-killing ability in vitro and in mice.Compared with the traditional lentiviral vector for the preparation of CAR-T cells in vitro,in vivo-reprogrammed CAR-T cells us-ing our CD8-targeted exosome delivery system,with higher transfection efficiency,shorter production period,lower cost,and eliminated the risk of insertion carcinogenesis.This strategy promises to bring a new era of universal CAR-T medicine,which can improve cancer immuno-therapy and may hold promise as a therapeutic platform to treat various diseases.

Objective:To establish a green fluorescent protein(GFP)and firefly luciferase(Luc)double-labeled Epstein-Barr virus(EBV)infec-ted B lymphoblastoid cell lines(B-LCL)and apply them to mouse models,then compare the advantages and disadvantages of models inocu-lated by intravenous(IV)or subcutaneous(SC).Methods:B lymphoblastoid cell lines double-tagged with GFP/Luc(B-LCL-GL)were con-structed through lentivirus transduction,puromycin intervention.Subcutaneous xenograft and hematogenous metastasis models were re-spectively established by subcutaneous or intravenous injection of B-LCL-GL cells at three concentrations in(NOD)/Prkdcscid/IL-2Rγnull(NPG)mice for in vivo bioluminescence imaging.Results:In the B-LCL-GL group,the ratio of the GFP-positive cell population was 92.5%,and the average luminescence intensity was as high as 4.80E+08 Photons/s,which was considerably higher than that of untreated B-LCLs.In the hematogenous metastasis models,tumor bioluminescence was initially located in the peritoneal area and then spread throughout the en-tire body between 7 and 28 days.In the subcutaneous xenograft models,strong central and weak peripheral tumor-related biolumines-cence signal was detected on day 7 in the three groups,which then spread throughout the body on day 28 in the high-dose group.Taken to-gether,there was no significant difference in tumor progression between the two routes of administration when using the same dose of B-LCL-GL cells.However,the survival analysis indicated that the IV injection group,in which all the mice ultimately died,had a shorter time frame for testing than that of the SC injection group,in which the mice survived until day 100 in the low-dose and medium-dose groups,thus allowing for long-term testing.Conclusions:GFP and Luc dual-positive B-LCLs were successfully established to generate hematogenous metastasis and subcutaneous xenograft models,which allow the monitoring of the location and size of lymphomas in vivo.It provide plat-form for the study of tumor characteristics and selecting anti-tumor drugs.