Cytotoxic T Lymphocytes (CTL) specific for CMV, adenovirus, and EBV can be generated from naive T cells for adoptive immunotherapy (145.22)

Abstract

Abstract Adoptive transfer of virus-specific T cells can effectively restore anti-viral immunity after stem cell transplant. However, standard protocols for eliciting virus-specific T cells from adult seropositive donors have been ineffective when applied to cord blood (CB) or virus-naïve adult donors. We tested alternative techniques for eliciting primary T cell responses in vitro. Culturing APC transduced with an Ad5f35pp65 vector and cytokines IL-2,7,12 and 15, we generated T cells specific for multiple viruses from CB and CMV-seronegative (CMVneg) donors. 9 CB-derived T cell lines contained 87% (range 81-94) CD8+ and 26% (12-40) CD4+ T cells. Specificity was determined in 51Cr release and IFN-γ ELISPOT assays against CMVpp65, adenovirus, and EBV targets. Results showed mean spot forming cells (SFC) following incubation with CMVpp65 (209;range 45-694), Adhexon (74;0-128), and EBV (157;23-291) targets. Further, CMVpp65-specific T cells expanded from 7 CMVneg adult donors showed mean 142(38-410) SFC to CMVpp65. CB and CMVneg-derived T cells derived only from naïve (CD45RA+/CCR7+) T cells and recognized "unconventional" CMVpp65 epitopes as identified by overlapping pp65 peptide pools using IFN-γ ELISPOT, suggesting an inherent difference between naïve and memory T cell responses to CMV. Virus-specific T cells can now be generated from naïve sources and could potentially be used clinically in these highest risk patients after transplant.