The invention provides a gene delivery vehicle and a gene of interest comprising at least one Ad35 element or a functional equivalent thereof, responsible for avoiding or diminishing neutralizing activity against adenoviral elements by the host to which the gene is to be delivered. A functional equivalent/homologue of an Ad35 (element) includes an adenovirus (element) which, like adenovirus 35, encounters pre-existing immunity in less than about 10% of the hosts to which it is administered for the first time, or which is capable in more than about 90% of the hosts to which it is administered of avoiding or diminishing the immune response.