Adenovirally transduced dendritic cells induce bispecific cytotoxic T lymphocyte responses against adenovirus and cytomegalovirus pp65 or against adenovirus and Epstein-Barr virus EBNA3C protein: A novel approach for immunotherapy

Cytomegalovirus (CMV), Epstein-Barr virus (EBV), and adenovirus (Ad) cause significant morbidity and mortality in immunocompromised patients undergoing allogeneic stem cell transplantation. We have established a procedure to generate polyclonal cytotoxic T lymphocyte (CTL) populations with specificity against Ad and CMV or against Ad and EBV. Healthy donor-derived dendritic cells (DCs) were transduced with recombinant adenovirus encoding either CMV pp65 or EBV EBNA3C and used to stimulate autologous T cells. Stimulated T lymphocytes displayed specific simultaneous cytotoxicity against CMV and adenovirus and to a lesser extent against adenovirus and EBV. Recombinant vaccinia virus encoding individual adenovirus proteins showed that the T cell response to the adenovirus was directed mainly against the capsid protein hexon. The frequency of IFN-gamma-secreting T cells was 0.02% for adenovirus alone, and 0.05 and 0.14% for adenoviruses encoding EBNA3C and pp65, respectively. pp65-specific CTLs killed autologous fibroblasts infected with the laboratory strain CMV AD169. The culture conditions were specific as alloreactive T cells were not expanded. Therefore, this approach could be considered in order to generate efficient virus cytolytic T cells to be used as adoptive immunotherapy in transplanted patients.