In Vitro Expansion of Anti-viral T Cells from Cord Blood by Accelerated Co-cultured Dendritic Cells

Abstract

Hematopoietic stem cell transplantation (HSCT) using unrelated cord blood (CB) donors is a suitable approach when an HLA-matched donor is not available. However, one important drawback is the risk of life-threatening viral infections prior to immune reconstitution, particularly from adenoviruses (AdVs). Although adoptive therapy with ex vivo expanded virus-reactive donor T cells has proven effective to treat these infections in HSCT recipients, the manufacturing process is complex and requires large numbers of cells, which is incompatible with CB donor units. Here, we have adapted our previous accelerated co-cultured dendritic cell (acDC) method, which allows to efficiently and rapidly expand peripheral blood T cells reactive to a given antigen, for use on limited CB material. Selected cytokine cocktails induced DC differentiation and maturation from unfractionated CB mononuclear cell cultures and simultaneously stimulated and expanded, within 10 days, functional CD8+ T cells specific for the model antigen MelanA or AdV immunodominant peptides. In addition, the use of G-Rex cultures yielded numbers of AdV-reactive CD8+ T cells compatible with adoptive cell therapy applications. Our acDC strategy, which uses reagents compatible with good manufacturing practices, may be promptly translated into the clinic for treating intercurrent infections in CB HSCT recipients. Keywords: cord blood, expansion, virus-specific T cells, dendritic cells, cytokine cocktail, stem cell transplantation