Immunogenicity of poxvirus vector avian influenza vaccines in Muscovy and Pekin ducks.
Fowlpox (FP)-vectored avian influenza (FP-AI) vaccines are used in 1-day-old chickens, but they have also recently been shown to be immunogenic in ducks. The objectives of this work were 1) to evaluate safety and to compare the immunogenicity in ducks of three poxvirus vectors (fowlpox, canarypox, and vaccinia) expressing the same hemagglutinin gene from an H5N1 isolate, 2) to study the effect of the dose of the FP-AI and the presence of an adjuvant in 1-day-old Pekin ducks on antibody response after a boost with inactivated vaccine given 3 wk later, and 3) to confirm the immunogenicity of such a heterologous prime-boost vaccination scheme in 1-day-old Muscovy ducks. Immunogenicity induced by the three poxvirus vectors was comparable, and the FP vector was selected for the other studies. As published previously, there was a strong dose effect of the FP-AI priming on the hemagglutination inhibition (HI) titers induced after the boost with an inactivated vaccine. In contrast, the two tested adjuvants did not significantly increase the activity of FP-AI priming. The heterologous prime-boost regimen given to both Muscovy and Pekin ducklings at 1 and 14 or 21 days of age, respectively, was shown to be at least as immunogenic as two administrations of inactivated vaccines given at 2 and 5 wk of age. However, HI antibody titers were of short duration for both vaccine schemes, and their persistence was heterogeneous among individual birds.
Merial S.A.S., R&D, 69007 Lyon, France. michel.bublot@merial.com
Michel
M
Bublot
Alexandra
A
Richard-Mazet
Sandrine
S
Chanavat-Bizzini
François-Xavier
FX
Le Gros
Michelle
M
Duboeuf
Anna
A
Stoll
Vilmos
V
Palfi
Eric
E
Niqueux
Olivier
O
Guionie
Nick
N
Dren
D000818:Animals; D018150:Avipoxvirus; D004334:Drug Administration Schedule; D004372:Ducks / Q000235:genetics*; D005260:Female; D053124:Influenza A Virus, H5N1 Subtype / Q000276:immunology; D007252:Influenza Vaccines / Q000008:administration & dosage / Q000276:immunology*; D005585:Influenza in Birds / Q000517:prevention & control*; D013997:Time Factors; D015164:Vaccines, Inactivated / Q000008:administration & dosage / Q000276:immunology; D014614:Vaccines, Synthetic / Q000008:administration & dosage / Q000276:immunology
D007252:Influenza Vaccines; D015164:Vaccines, Inactivated; D014614:Vaccines, Synthetic