Objective: To investigate immunity of a recombinant adenovirus vaccine (rAdV) containing codon-modified neuraminidase (Mod. NA) gene of H5N1 influenza virus in BALB/c mice and to screen for appropriate dose.
Methods: BALB/c mice were immunized with the rAdV-Mod.NA vaccine intramuscularly twice (double injection at 0 and 4th week) in three groups, low dosage (10(5) TCID50 per dose), medium dosage (10(7) TCID50 per dose) and high dosage (10(9) TCID50 per dose). The effect of humoral and cell-mediated immunity were analysed at 5th week.
Results: (1) The rAdV-Mod.NA vaccine could elicit both humoral and cell-mediated robust NA specific immunity in mice by neuraminidase inhibitor assay and IFN-gamma ELISpot assay; (2) 10(7) TCID50 per dose was the appropriate dose; (3) Peptide NA(109-124): CRTFFLTQGALLNDKH and peptide NA(182-199): AVAVLKYNGIITDTIKSW were the dominant epitopes for neuraminidase-immunized BALB/c mice, which was screened out from the whole length of neuraminidase of an H5N1 virus, A/Anhui/1l/2005.
Conclusion: The recombinant adenovirus NA could induce specific humoral and cellular immune responses in BALB/c after immunization, which suggest rAdV-Mod.NA vaccine was a potential vaccine candidate against H5N1 influenza and worthy of further investigation.