Co-administration of adenovirus vector expressing CTLA4-Ig prolongs transgene expression in the brain of mice sensitized with adenovirus

The duration of transgene expression in the brain is known to be shortened by previous sensitization to adenovirus. In order to prolong transgene expression, adenovirus vectors expressing CTLA4-Ig (AdCTLA), which blocks the B7-CD28 co-stimulatory signals required for T-cell activation, were used. Local administration of AdCTLA into the brain suppressed both the cellular and humoral immune responses to adenovirus vectors, and prolonged the duration of transgene expression. AdCTLA may be an effective tool for repeated gene transfer.