Induction of tumor specific cytotoxic T lymphocyte by using transfer of co-simulatory molecule gene

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Interaction between the costimulatory molecule B7-1 (CD80) on antigen-presenting cells and its counter-receptor CD28 on T lymphocyte plays a key role in the induction of cell-mediated immune responses including cancer. Many solid tumor lack expression of B7-1 and this has been suggested to contribute to the failure of immune recognition of these diseases. Based on this knowledge, we hypothesized that co-stimulatory signal delivered through B7-1 or B7-2 molecule expressed on lung cancer cells using replication deficient adenovirus vector (Ad) would induce tumor-specific cytotoxic T lymphocyte (CTL). To evaluate this hypothesis, we constructed two Ads ; AdCMVhB7 (am E1^- Ad5 based vector containing human B7-1 cDNA driven by cytomegalovirus immediate early promoter and enhancer) ; AdNull (above same vector withour expression of exogenous gene) as control. Theoretical advantages of Ad consist in capacity of high efficient gene transduction. Using these Ads, generation of tumor specific CTL … More was studied in a primary syngeneic mixed lymphocyte tumor culture by using both lung cancer cells and peripheral blood lymphocytes obtained from patients with lung cancer. Inoculation of lung cancer cells with 10 multiplicity of infection of AdCMVhB7 resulted in rapid and efficient cell surface expression of B7-1 molecule (>90% of cell at 24h). Cytolytic activity of lymphocytes by using ^<51>Cr-releasing assay (E/T=40) demonstrated that effector lymphocytes induced by hB7-1(+)lung cancer cells treated with AdCMVhB7 could lyse 45% parental lung cancer cells hB7-1(-) with a maximum lysis of 62%, in addition, the effector lymphocytes could not lyse the irrelevant syngeneic fibroblast. In countrast, effector lymphocytes induced by lung cancer cells treated with AdNull as control virus or PBS as control could not lyse parental lung cancer cells at all. Furthermore, cytolytic activity of the effector lymphocytes induced by B7-1 transduced lung cancer cells was inhibited by addition of anti-CD3 antibody (10ug/ml). These data suggested that effector lymphocytes induced by lung cancer treated with AdCMVhB7 have a character of tumor-specific CTL.Adenovirus mediated-hB7-1 gene transfer may be a useful means for gene therapy for lung cancer in application of adoptive immunotherapy. Less