Combination of H120 and 1/96 avian infectious bronchitis virus vaccine strains protect chickens against challenge with IS/1494/06 (variant 2)-like infectious bronchitis virus

M. HABIBI, V. KARIMI, A. G. LANGEROUDI, S. A. GHAFOURI, M. HASHEMZADEH, R. K. FARAHANI, H. MAGHSOUDLOO, H. ABDOLLAHI, P. SEIFOURI
2017 Acta virologica  
Avian infectious bronchitis (IB) is a worldwide chicken disease, caused by avian infectious bronchitis virus (IBV) which infects all commercial poultry lines. Th e present study was done to evaluate protection caused by two diff erent serotype vaccines (Massachusetts and 793/B) in order to evaluate protection against challenge with IS/1494/06-like virus (variant 2-like virus), which is prevalent in the Middle East. SPF chickens were divided into four groups (n = 20). First and second group as
more » ... d second group as negative control group and non-vaccinated-challenged group received no vaccine. Groups 3 and 4 received H120-H120 and H120-1/96 IBV vaccine strains at the 1 st and 14 th day, respectively. Twenty one days aft er last vaccination, non-vaccinatedchallenged group and vaccinated group were challenged using variant 2-like IBV. Serum samples were collected before challenge to measure humoral immune response of chickens. Five days aft er challenge, the tissue samples from the trachea, lungs and kidneys were taken to evaluate cilliary activity, viral load (quantitative real-time RT-PCR), and histopathological evaluation. Clinical sign scores were also recorded aft er challenge. Overall, the results showed a protective effi cacy of the used vaccination program. Best cross protection (69.2%) was obtained in the H120-1/96 vaccinated group. Virus replication of the challenged virus in H120-1/96 group compared with H120-H120 group showed a signifi cant reduction of viral load in trachea (1.5×10 3 compared to 503) and kidneys. Clinical sign scores of the challenged groups showed signifi cant eff ect of the vaccination program to reduce clinical signs. Th e trachea pathological scores and histopathological fi ndings in the lungs and kidneys also confi rmed better protective effi cacy of vaccinated groups. In conclusion, using combination of heterologous IBV vaccine serotypes (Massachusetts and 793/B) would be a better strategy to control variant 2-like viruses, but more evaluation is needed using other circulating isolates to fi nd the best combination of vaccines. Abbreviations: GMT = geometric mean titer; IB = infectious bronchitis; IBV = infectious bronchitis virus; Mass = Massachusetts serotype; SPF = specifi c pathogen free
doi:10.4149/av_2017_02_04 pmid:28523921 fatcat:vd2edk4mwvarfntneg2rybx33y