Fusion of DsbA to the N-terminus of CTL chimeric epitope, F/M2:81-95, of respiratory syncytial virus prolongs protein- and virus-specific CTL responses in Balb/c mice

In an effort to seek a means of inducing long lasting respiratory syncytial virus-specific CTL responses in mice, we constructed a new recombinant protein, DsbA–F/M2:81-95, by fusing carrier protein DsbA (disulfide bond isomerase) to the N-terminus of CTL chimeric epitope F/M2:81-95 of this virus. DsbA–F/M2:81-95 can induce effectively virus-specific CTL responses as well as protective immunity without association with enhanced disease. Furthermore, compared with F/M2:81-95 alone, it increases the longevity of CTL responses in vivo up to 2.93 folds. Our study emphasizes that appropriate stimulation of non-antigen-specific T helper cells is essential to induce long lasting CD8+ CTL, and also implies DsbA–F/M2:81-95 may be a promising candidate for RSV vaccine development since it is an efficacious and safe immunogen.