A recombinant replication-defective human adenovirus type 3: a vaccine candidate.

Human adenovirus type 3 (HAdV-3) cause respiratory infections globally. There is no safe and efficient HAdV-3 vaccine thus far. In this report, a replication-defective human adenovirus type 3 was constructed by deletion of the whole E1 gene. A HEp-2 cell-based cell line designated HEp-2/E1 was generated and was shown to complement the function of E1 deleted mutant. A partial genome (9.5-100 mu) of HAdV-3 was cloned into pPolyII vector to be a backbone plasmid. A shuttle vector carrying eGFP gene was also constructed. The backbone and shuttle plasmids were co-transfected into the HEp-2/E1 cell line and 293 cell line separately. Typical cytopathic effect (CPE) appeared in the HEp-2/E1, but not in 293 cells 2 weeks after transfection. Wild-type HAdV-3 is neutralized by the sera from the mice immunized with the recombinant HAdV-3. The results demonstrated that the recombinant adenovirus type 3 may serve as a HAdV-3 vaccine candidate.