Absence of germline infection in male mice following intraventricular injection of adenovirus

The possibility of inadvertent exposure of gonadal tissue to gene therapy v ectors has raised safety concerns about germline infection. We show here th at the receptor for coxsackie B viruses and adenoviruses 2 and 5 (CXADR) is expressed in mouse germ cells, suggesting the possibility that these virus es could infect germ cells. To directly assess the risk of germline infecti on in vivo, we injected an adenovirus carrying the germ-cell-specific prota mine promoter fused to the bacterial lacZ reporter gene into the left ventr icular cavity of mice and then monitored expression of the reporter gene in germ cells. To differentiate between infection of stem cells and different iating spermatogenic cells, we analyzed expression of the reporter cassette at different times after viral delivery. Under all conditions tested, mice did not express the Escherichia coil beta -galactosidase protein in develo ping spermatids or in mature epididymal spermatozoa. Primary germ cells cul tured in vitro were also refractory to adenoviral infection. Our data sugge st that the chance of vertical germline transmission and insertional mutage nesis is highly unlikely following intracoronary adenoviral delivery.