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J Virol. Acquisition of a polybasic hemagglutinin cleavage site by a low-pathogenic avian influenza virus is not sufficient for immediate transformati

Giuseppe

Giuseppe

Emeritus
J Virol. 2009 Mar 18. [Epub ahead of print]

Acquisition of a polybasic hemagglutinin cleavage site by a low-pathogenic avian influenza virus is not sufficient for immediate transformation into a highly pathogenic strain.

Stech O, Veits J, Weber S, Deckers D, Schr?er D, Vahlenkamp TW, Breithaupt A, Teifke J, Mettenleiter TC, Stech J. - Friedrich-Loeffler-Institut, Federal Research Institute for Animal Health, S?dufer 10, 17493 Greifswald - Insel Riems, Germany.

Highly pathogenic avian influenza viruses (HPAIV) differ from all other strains by a polybasic cleavage site in their hemagglutinin. All these HPAIV share the H5 or H7 subtype. In order to investigate whether the acquisition of a polybasic cleavage site by an avirulent avian influenza virus strain with a hemagglutinin other than H5 or H7 is sufficient for immediate transformation into an HPAIV, we adapted the hemagglutinin cleavage site of A/Duck/Ukraine/1/1963 (H3N8) to those of the HPAIV A/Chicken/Italy/8/98 (H5N2), A/Chicken/HongKong/220/97 (H5N1) or A/Chicken/Germany/R28/03 (H7N7) and generated the recombinant wild-type and cleavage site mutants.
In contrast to the wild-type, multicycle replication of these mutants in tissue culture was demonstrated by positive plaque assays and viral multiplication in the absence of exogenous trypsin.
Therefore, in-vitro all cleavage site mutants resemble an HPAIV.
However, in chicken they did not exhibit high pathogenicity, although they could be re-isolated from cloacal swabs to some extent indicating enhanced replication in-vivo.
These results demonstrate that beyond the polybasic hemagglutinin cleavage site, the virulence of HPAIV in chicken is based on additional pathogenicity determinants within the hemagglutinin itself or in the other viral proteins.
Taken together, these observations support the notion that acquisition of a polybasic hemagglutinin cleavage site by an avirulent strain with a non-H5/H7 subtype is only one among several alterations necessary for evolution into an HPAIV.

PMID: 19297482 [PubMed - as supplied by publisher]
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Re: J Virol. Acquisition of a polybasic hemagglutinin cleavage site by a low-pathogenic avian influenza virus is not sufficient for immediate transformation into a highly pathogenic strain.

maybe it's the cleavage site itseld, the exact combination ?

that Ukraine duck may have multiple bases but avirulent combination.
 
Re: J Virol. Acquisition of a polybasic hemagglutinin cleavage site by a low-pathogenic avian influenza virus is not sufficient for immediate transformation into a highly pathogenic strain.

gsgs said:
maybe it's the cleavage site itseld, the exact combination ?

that Ukraine duck may have multiple bases but avirulent combination.
Click to expand...
All of the clade 2.2 H5N1 (all "Asian" H5N1) have a polybasic cleavage site, and asymptomatic waterfowl is common (in MANY countries, including Russia, Germany and Egypt). The asymptomatic birds (and cats in Austria and Germany) are NOT linked to "combinations". In 2005 the "Mission report" from Russia detailed TWO DOZEN bird species that were hunter killed and H5N1 positive - with polybasic cleavage sites).
 
Re: J Virol. Acquisition of a polybasic hemagglutinin cleavage site by a low-pathogenic avian influenza virus is not sufficient for immediate transformation into a highly pathogenic strain.

they are talking about chickens - not ducks
 
Re: J Virol. Acquisition of a polybasic hemagglutinin cleavage site by a low-pathogenic avian influenza virus is not sufficient for immediate transformation into a highly pathogenic strain.

gsgs said:
they are talking about chickens - not ducks
Click to expand...
The Ukraine duck was a duck (waterfowl).
 
Re: J Virol. Acquisition of a polybasic hemagglutinin cleavage site by a low-pathogenic avian influenza virus is not sufficient for immediate transformation into a highly pathogenic strain.

ahh, from 1963.
They tested in cHickens

> However, in chicken they did not exhibit high pathogenicity
 
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