A study on antigenic relatedness protection of vaccine H9 virus against H9 virus isolates in 1389 and 1390
2011
Mohammad Javad Mehrabanpour
Avian influenza (AI) is a viral respiratory disease in wild and domesticated bird and cause serious economic losses to poultry industry of Iran. In Iran, avian influenza viruses outbreak have been frequently recoded since 1998. The inactivated AI vaccine has been used as part of an AI disease control in poultry. Serum hemagglutination inhibition (HI) antibody titers are the most commonly measured by correlate of protection and immunity induced by influenza virus vaccines provides optional protection against viruses that are antigenically closely matched with those in the vaccine. Six of the isolates were selected randomly to produce experimental vaccine. Seven groups (each group consisted 10 of 4 week-old-SPF chicken) were selected and six groups of them were immunized with experimentally prepared vaccines, and one group (positive control) was vaccinated with commercial vaccine. Fourteen days after vaccination blood sample was collected from each bird and serum was separated to perform HI using each isolate as well as vaccinal strain.for evaluation of potency of razi vaccine, challenge of vaccinal group was performed by 10 virus isolates. Tracheal and cloacal swabs were taked in 1, 3, 5, 7, 9 days after challenge for evaluation of virus shedding by EID50. The HI results were positive with any influenza virus isolates and vaccinal strain also, although the obtained titers showing variations among isolates being used. The result indicates that the present vaccine (Razi vaccine) can be protected chicken against 6 isolated uses in this study and none protected against 4 virus isolates. Results of shedding confirmed the variation of vaccine potency against some variants.
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