Immunity Protection of H5 Subtype Avian Influenza DNA Vaccine pCAGGoptiHA5 from HPAIV Lethal Challenge

For evaluating the efficacy of DNA vaccine pCAGGoptiHA5,6 groups of 3-week-old SPF chickens were intramuscular inoculated singly and boosted with 100 μg or 10 μg of pCAGGoptiHA5 in 200 μL volume.A group of chickens were injected with 200 μL PBS as controls.Sera were collected weekly after vaccination for detecting the HI,NT and AGP antibodies.Four-weeks after the single vaccination,two weeks after the boost,all chickens were challenged with 100LD_(50) of highly pathogenic A/Goose/GuangDong/1/96(H5N1)strain,oropharyngeal and cloacal swab specimens were collected from all chickens 3,5 and 7 days after inoculation for titration of virus in eggs,and chickens were observed daily for disease signs and deaths for 2 weeks.Results shown that 100 μg or 10 μg pCAGGoptiHA5 boosted chickens,100 μg pCAGGoptiHA5 priming chickens were completely protected from virus challenge(no disease sign,no virus shedding and no death).The constructed pCAGGoptiHA5 could protect chickens from lethal H5N1 virus challenge even at the low dose of 10 μg,implied the potential possibility for the commercialization of(avian) influenza DNA vaccine in the future.