Both HAdV5 vectors were used at the same vector dose of 30 vp/cell and in complex with BVCAR. No morphological changes were observed in both the mock-transduced and BVCARHAdV5-GFP-transduced FLS at 24 h post transduction (Fig. 2a,b,g,h). However, both human and rat FLS transduced with BVCARHAdV5-PUMA show massive cell death (Fig. 2c,i). To mimic the inflammatory conditions in arthritic joints, human and rat FLSs were pre-treated with proinflammatory cytokines TNFα and IL-17 before vector transduction (Fig. 2d,e,f,j,k,l). Similarly, massive cell death was observed in both types of FLS transduced with BVCARHAdV5-PUMA (Fig. 2f,l). This implied that cell death of both human and rat FLS could be induced by an HAdV5 vector expressing a proapoptotic gene such as PUMA, and achieved with the cooperation of a BVCAR vector. Since rat FLS are sensitive to PUMA-induced apoptosis, a rat in vivo model of arthritis could be evaluated with the BVCARHAdV5-PUMA vector.Fig. 2Cell death of human and rat FLS induced by BVCARHAdV5-PUMA. Cultures of human and rat FLS were non-treated a–c,g–i or treated d–f,j–l with proinflammatory cytokines, TNFα and IL-17. The FLS samples were mock-infected a,d,g,j, infected with BVCARHAdV5-GFP b,e,h,k or infected with BVCARHAdV5-PUMA c,f,i,l. Note the rounding-up of FLS after transduction with BVCARHAdV5-GFP in c,f,i,l. Scale bars, 20 μm