Microb Pathog. 2016 Jun 11. pii: S0882-4010(16)30194-2. doi: 10.1016/j.micpath.2016.06.011. [Epub ahead of print]
Reverse genetics based rgH5N2 vaccine provides protection against high dose challenge of H5N1 avian influenza virus in chicken.

Bhatia S1, Khandia R2, Sood R2, Bhat S2, Siddiqui A2, Jahagirdhar G2, Mishra S2, Mishra A2, Pateriya AK2, Kulkarni DD2.
Author information


An inactivated vaccine was developed using the rgH5N2 virus (6 + 2 reassortant) generated by plasmid based reverse genetics system (RGS) with WSN/33/H1N1 as backbone virus. Following mutation of the basic amino acid cleavage site RRRKKR*GLF to IETR*GLF, the H5-HA (haemagglutinin) gene of the selected donor H5N1 virus (A/chicken/West Bengal/80995/2008) of antigenic clade 2.2 was used along with the N2-NA gene from H9N2 field isolate (A/chicken/Uttar Pradesh/2543/2004) for generation of the rgH5N2 virus. A single dose (0.5 ml/bird) of the inactivated rgH5N2 vaccine protected 100% of the vaccinated chickens (n = 10) on 28th dpv (early challenge) and 90% of the vaccinated chickens (n = 10) on 200 dpv (late challenge) against high dose challenge with HPAI virus (109 EID50/bird). Challenge virus shedding via oropharynx and cloaca of the vaccinated chickens was detectable by realtime RT-PCR during 1-5 dpc and 1-9 days dpc in the early and the late challenge, respectively. The protective level of antibodies (mean HI titre > 128) was maintained without booster vaccination for 200 days. The present study provides the experimental evidence about the extent of protection provided by a reverse genetics based vaccine for clade 2.2 H5N1 viruses against challenge with high dose of field virus at two different time points (28 dpv and 200 dpv). The challenge study is uniquely different from the previous similar experiments on account of 1000 times higher dose of challenge and protection at 200 dpv. The protection and virus shedding data of the study may be useful for countries planning to use H5 vaccine in poultry especially against the clade 2.2 H5N1 viruses.
Copyright 2016. Published by Elsevier Ltd.


Avian influenza; H5N1; Reverse genetics; Vaccine

PMID: 27296706 [PubMed - as supplied by publisher]