The effect of pre-existing adenovirus-specific immunity on immune responses induced by recombinant adenovirus expressing glycoprotein D of bovine herpesvirus type 1

We investigated whether pre-existing adenovirus-specific immunity influence d the development of immunity to a foreign antigen expressed by recombinant adenovirus. Active adenovirus-specific immunity was induced in cotton rats by i.n. administration of wild type human adenovirus type 5 (HAd5) two wee ks before immunisation with a HAd5 vector expressing the glycoprotein D (gD ) of bovine herpesvirus type 1 (gD-dE3 recombinant adenovirus). Active aden ovirus-specific immunity inhibited gD-specific immune responses, following either i.n. or gastrointestinal immunisation with gD-dE3. An inhibitory eff ect was present even if infection with HAd5 and immunisation with gD-dE3 we re 13 weeks apart. Passive transfer of adenovirus specific antibodies to co tton rats one day before immunisation, however, did not significantly inhib it gD-specific immune responses induced by i.n. immunisation with gD-dE3. R epealed administration of an adenovirus vector, therefore, may have a limit ed ability to deliver antigen, while passive immunity to adenovirus may not interfere with the success of immunisation. (C) 1999 Elsevier Science Ltd. All rights reserved.