Altered tropism of recombinant bovine adenovirus type-3 expressing chimeric fiber

Recombinant bovine adenovirus-3 (BAV-3) has been used as a gene delivery vector for vaccination of calves. However, its usefulness as a vector for non-bovine species is limited due to poor transduction efficiency. To develop BAV-3 based vector for non-bovine species, we determined the feasibility of making targeted BAV-3 vector by modifying its natural tropism. We constructed a chimeric virus, BAV600, in which the knob region of the BAV-3 fiber protein was replaced with that from human adenovirus type 5 (HAV-5). Unmodified BAV-3 vector (BAV304) was able to transduce and direct the expression of green fluorescent protein (GFP) in non-bovine cells, with low efficiency. In contrast, the transduction efficiency of BAV600 in these cells was increased by 3-67-fold. Although, expression of early and late genes was detected in non-human cells, no progeny virus (BAV600) was detected in these cells. Our results suggest that it is possible to develop BAV-3 vectors with tropism for non-bovine species.