Mutants of influenza virus.

Trypsin-resistant protease activation mutants of an influenza virus.

New classes of mutants of influenza virus A/seal/Mass/1/80 are described in which the haemagglutinins (HA) have lost their protease cleavability by trypsin, but can be activated by elastase, chymotrypsin or thermolysin in different cell types. The same proteases that were required for activation of infectivity of the mutants also activated haemolysis and cell-fusing properties. The protease act...

Emergence of HA mutants during influenza virus pneumonia.

During the influenza pandemic of 2009, the number of viral pneumonia cases showed a marked increase in comparison with seasonal influenza viruses. Mutations at amino acid 222 (D222G mutations) in the virus hemagglutinin (HA) molecule, known to alter the receptor-recognition properties of the virus, were detected in a number of the more severely-affected patients in the early phases of the pande...

Influenza B virus NS1-truncated mutants: live-attenuated vaccine approach.

Type B influenza viruses can cause substantial morbidity and mortality in the population, and vaccination remains by far the best means of protection against infections with these viruses. Here, we report the construction of mutant influenza B viruses for potential use as improved live-virus vaccine candidates. Employing reverse genetics, we altered the NS1 gene, which encodes a type I interfer...

2009 H1N1 Influenza Virus Seroepidemiology

Isolation and Identification of Avian Influenza Virus H9N2 Subtype