Research paper
Passive inhalation of dry powder influenza vaccine formulations completely protects chickens against H5N1 lethal viral challenge

https://doi.org/10.1016/j.ejpb.2018.10.008Get rights and content
Under a Creative Commons license
open access

Abstract

Bird to human transmission of high pathogenicity avian influenza virus (HPAIV) poses a significant risk of triggering a flu pandemic in the human population. Therefore, vaccination of susceptible poultry during an HPAIV outbreak might be the best remedy to prevent such transmissions. To this end, suitable formulations and an effective mass vaccination method that can be translated to field settings needs to be developed. Our previous study in chickens has shown that inhalation of a non-adjuvanted dry powder influenza vaccine formulation during normal breathing results in partial protection against lethal influenza challenge. The aim of the present study was to improve the effectiveness of pulmonary vaccination by increasing the vaccine dose deposited in the lungs and by the use of suitable adjuvants. Two adjuvants, namely, Bacterium-like Particles (BLP) and Advax, were spray freeze dried with influenza vaccine into dry powder formulations. Delivery of dry formulations directly at the syrinx revealed that BLP and Advax had the potential to boost either systemic or mucosal immune responses or both. Upon passive inhalation of dry influenza vaccine formulations in an optimized set-up, BLP and Advax/BLP adjuvanted formulations induced significantly higher systemic immune responses than the non-adjuvanted formulation. Remarkably, all vaccinated animals not only survived a lethal influenza challenge, but also did not show any shedding of challenge virus except for two out of six animals in the Advax group. Overall, our results indicate that passive inhalation is feasible, effective and suitable for mass vaccination of chickens if it can be adapted to field settings.

Abbreviations

HPAIV
high pathogenicity avian influenza virus
BLP
bacterium-like particles
WIV
whole inactivated virus vaccine
SFD
spray freeze drying
HI
hemagglutination inhibition
EID50
50% embryo infectious dose
TCID50
50% tissue culture infective dose

Keywords

Passive
Influenza
Powders
Inhalation
Adjuvants
Pulmonary
Challenge
Protection

Cited by (0)