The objective of the study was to compare efficacy of two fowlpox (FP) vector vaccines (FP-AI) against H5N1 highly pathogenic avian influenza (HPAI): one (vFP89) expressing the native hemagglutinin (HA) gene from H5N8 A/turkey/Ireland/1378/83 and the other (vFP2211) expressing a modified synthetic HA gene from H5N1 A/chicken/Indonesia/7/2003. Four groups of 20 1-day-old specific-pathogen-free chickens were made: Groups 1 and 2 were immunized with 3 log10 tissue-culture infectious dose 50% (TCID50) of vFP89 and vFP2211, respectively, whereas group 3 was immunized with vFP89, but received a booster immunization at 2 wk of age with an inactivated vaccine containing A/turkey/Wisconsin/68 H5N9 virus (inH5N9); group 4 was left unvaccinated. Ten birds from each group were challenged on day 21 with A/turkey/Turkey/1/2005 clade 2.2 H5N1 HPAI virus. The 10 other chickens from each group were put in contact with their groupmates on day 22. FP-AI induced low hemagglutination inhibition (HI) titers before challenge (GMT <4 log2) and an HI titer boost was observed 1 wk after the inH5N9 boost. All directly challenged and 9/10 nonvaccinated contact chickens died after challenge (mean death time of 2.3 and 6.1 days, respectively) and most of them shed virus before death via cloacal and buccal routes. All vaccinated birds were clinically protected from HPAI challenge. One (vFP2211), 2 (vFP89 inact.), or 3 (vFP89) out of the 10 directly challenged vaccinated chickens shed virus via the buccal route 2–5 days postinfection. No shedding was detected in the contact-challenged vaccinated birds. Altogether, these data show excellent levels of protection in all three vaccinated groups, and therefore no detectable effect of the origin of the inserted H5 gene on protection under these tested conditions.
You have requested a machine translation of selected content from our databases. This functionality is provided solely for your convenience and is in no way intended to replace human translation. Neither BioOne nor the owners and publishers of the content make, and they explicitly disclaim, any express or implied representations or warranties of any kind, including, without limitation, representations and warranties as to the functionality of the translation feature or the accuracy or completeness of the translations.
Translations are not retained in our system. Your use of this feature and the translations is subject to all use restrictions contained in the Terms and Conditions of Use of the BioOne website.
Vol. 54 • No. s1