Human cytomegalovirus (CMV) remains a serious cause of morbidity and mortality in recipients of allogeneic stem cell transplants (SCT). Current therapies for CMV rely upon drugs that cause myelosuppression and nephrotoxicity, thus limiting their use. Riddell and associates have demonstrated that SCT patients can achieve normal levels of CMV specific cellular immunity following infusions of donor-derived, CMV specific CTL. These technologies, however, are limited by the time and reagents required to cultivate antigen presenting cells (APC), such as donor-derived skin fibroblasts, as well as T cell clones. The applicant's laboratory has encoded pp65, the immunodominant CMV peptide, in a retrovirus (MSCV), and has successfully transduced B lymphoblastoid cells lines (BLCL) and SF to achieve expression of this peptide. Using a single APC, he has developed CMV pp65 and EBV specific, polyclonal CTL. These CTL are MHC Class I restricted and CD8+. These studies will examine the feasibility of cultivating CMV/EBV specific CTL using pp65 transduced BLCL from stem cell donors. He will apply these bi-specific CTL for CMV and EBV prophylaxis in stem cell transplant patients receiving T cell depleted (TCD), matched or partially matched related donor transplants. He will characterize the CMV and EBV specific immunity of these patients at intervals post-infusion and examine the TCR Vbeta repertoire and HLA restriction of cultivated CTL and patient PBMC. Due to risks of graft-versus-host disease (GVHD) if using non-specific donor PBMC for immunotherapy, as well as the morbidity of anti-CMV drugs, this form of therapy may have a significant impact on this patient population. Using a quantitative, competitive PCR assay for CMV, he will measure levels of CMV DAN from the peripheral blood of recipients of CMV/EBV CTL infusions. A semi-quantitative PCR assay will be used to measure levels of EBV DNA. While adoptive immunotherapy is a possibility for patients receiving peripheral blood stem cell or bone marrow transplants, it is not an option for recipients of cord blood transplants or for patients who have donors who are CMV seronegative. As a part of these studies, the applicant will examine the possibility of developing CMV specific CTL using pp65 BLCL from CMV seronegative donors and from CB lymphocytes.
| Sun, Qi; Burton, Robert L; Lucas, Kenneth G (2002) Cytokine production and cytolytic mechanism of CD4(+) cytotoxic T lymphocytes in ex vivo expanded therapeutic Epstein-Barr virus-specific T-cell cultures. Blood 99:3302-9 |
