Human PBMC-derived dendritic cells transduced with an adenovirus vector induce cytotoxic T-lymphocyte responses against a vector-encoded antigen in vitro

Dendritic cells (DC) are among the most potent antigen-presenting cells kno wn and play an important role in the initiation of antigen-specific T-lymph ocyte responses. Several recent studies have demonstrated that DG expressin g vector-encoded tumour-associated antigens can induce protective and thera peutic immunity in murine cancer models. In the current study we set out to examine in vitro the utility of adenovirus vectors in the transduction of human DC for the induction of antigen-specific T-lymphocyte responses again st a defined vector-encoded antigen. DC were derived from the adherent frac tion of PBMC by culture in defined medium containing GM-CSF and IL-4. A rep lication-defective E1/E3-deleted type 5 adenovirus vector encoding bacteria l beta-galactosidase (beta-gal) under the transcriptional control of a CMV promoter was used to transduce DC at multiplicities of infection (MOI) up t o 1000. While high MOI were required to achieve efficient transduction ther e was no significant effect on DC morphology, immunophenotype or potency in allogeneic lymphocyte proliferation assays. Furthermore, transduced DG-ind uced antigen-specific CTL activity against adenoviral proteins and more sig nificantly, the vector-encoded antigen beta-gal. These data clearly demonst rate the potential of adenovirus vectors in anticancer DC vaccine strategie s and provide an important link between existing animal data and human clin ical application.