Immunotherapy of Adenovirus Infections in Stem Cell Transplnt Recipients

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The goal of this proposal is to identify potential immunotherapeutic targets for treatment of adenovirus disease in cancer patients who receive allogeneic stem cell transplants. Although adenoviruses can cause fatal infections post- stem cell transplant, there is no established therapy. Based on the successful use of donor lymphocyte infusions to treat other viral infections such as Epstein Barr virus, we propose that T cell immunotherapy may help control adenovirus disease post-transplant. Our lab was the first to document adenovirus -specific memory CD4+ and CD8+ T cell responses in peripheral blood from most healthy adults. We have identified hexon as the immunodominant capsid protein target, containing epitopes highly conserved among different adenovirus serotypes. However, it is not known whether hexon-specific T cell responses alone are adequate to control acute infection. We hypothesize that, in vivo, T cells targeted to regulatory adenovirus proteins expressed early in infected cells may be more efficient than hexon-specific J cells because they will 1)eliminate infected cells prior to viralreplication and 2) recognize cells prior to adenovirus ¿3 19k-mediated inhibition of MHC class l-restricted antigen presentation. We propose to identify major early protein targets by analysis of memory adenovirus-specific T cell responses in healthy adults against individual proteins and synthetic peptides. Additionally, patterns of virus-specific T cell responses in stem cell transplant recipients who develop acute adenovirus infections will be evaluated by IFN-y ELISPOT, cytokine flow cytometry, and cytotoxic T cell assays and correlated with clinical outcomes. These studies will provide the tools and scientific basis for a future immunotherapy trial for the treatment of adenovirus disease. It is anticipated that this work will lead to an improvement in the survival of patients who undergo stem cell transplants.