tetano
Editor, Senior Moderator
Vaccine. 2014 Mar 24. pii: S0264-410X(14)00363-6. doi: 10.1016/j.vaccine.2014.03.019. [Epub ahead of print]
A model for early onset of protection against lethal challenge with highly pathogenic H5N1 influenza virus.
R?hrs S1, Kalthoff D1, Beer M2.
Author information
Abstract
Highly pathogenic avian influenza viruses (HPAIV) H5N1 sporadically cause severe disease in humans and involve the risk of inducing a pandemic by gaining the ability for human-to-human transmission. In na?ve poultry, primarily gallinaceous birds, the virus induces fatal disease and the used inactivated vaccines occasionally are unable to provide efficient and early onset of protection. Therefore, optimized vaccines must be developed and evaluated in model systems. In our study, we tested a novel H5 neuraminidase-deleted influenza A virus variant to analyze the induction of a very early onset of immunity. Ferrets, mice and chickens were each immunized with a single vaccine dose seven, three and one day before lethal challenge infection, respectively. Sound protection was conferred in 100% of animals immunized seven days prior to challenge infection. In these animals, no clinical signs were observed, and no challenge virus RNA was detected by real-time RT-PCR analyses of swabs, nasal washings, and organ samples. Moreover, the attenuated modified-live virus variant protected all chickens, mice, and ferrets as early as three days after vaccination against severe clinical signs. Chickens and ferrets developed hemagglutinin-specific antibodies after seven days, but no neuraminidase-specific antibodies, making this kind of neuraminidase-negative strain suitable for the DIVA ("differentiating vaccinated from infected animals") strategy.
Copyright ? 2014 Elsevier Ltd. All rights reserved.
KEYWORDS:
Avian influenza virus, Early onset of protection, H5N1, Neuraminidase
PMID:
24674664
[PubMed - as supplied by publisher]
http://www.ncbi.nlm.nih.gov/pubmed/24674664
A model for early onset of protection against lethal challenge with highly pathogenic H5N1 influenza virus.
R?hrs S1, Kalthoff D1, Beer M2.
Author information
Abstract
Highly pathogenic avian influenza viruses (HPAIV) H5N1 sporadically cause severe disease in humans and involve the risk of inducing a pandemic by gaining the ability for human-to-human transmission. In na?ve poultry, primarily gallinaceous birds, the virus induces fatal disease and the used inactivated vaccines occasionally are unable to provide efficient and early onset of protection. Therefore, optimized vaccines must be developed and evaluated in model systems. In our study, we tested a novel H5 neuraminidase-deleted influenza A virus variant to analyze the induction of a very early onset of immunity. Ferrets, mice and chickens were each immunized with a single vaccine dose seven, three and one day before lethal challenge infection, respectively. Sound protection was conferred in 100% of animals immunized seven days prior to challenge infection. In these animals, no clinical signs were observed, and no challenge virus RNA was detected by real-time RT-PCR analyses of swabs, nasal washings, and organ samples. Moreover, the attenuated modified-live virus variant protected all chickens, mice, and ferrets as early as three days after vaccination against severe clinical signs. Chickens and ferrets developed hemagglutinin-specific antibodies after seven days, but no neuraminidase-specific antibodies, making this kind of neuraminidase-negative strain suitable for the DIVA ("differentiating vaccinated from infected animals") strategy.
Copyright ? 2014 Elsevier Ltd. All rights reserved.
KEYWORDS:
Avian influenza virus, Early onset of protection, H5N1, Neuraminidase
PMID:
24674664
[PubMed - as supplied by publisher]
http://www.ncbi.nlm.nih.gov/pubmed/24674664