Darwyn Kobasa

TL;DR: The SD0 mutant of influenza virus A/WSN/33 (WSN), characterized by a 24-amino-acid deletion in the neuraminidase stalk, does not grow in embryonated chicken eggs because of defective NA function, demonstrating that balanced HA-NA functions are necessary for efficient influenza virus replication.

TL;DR: Although conservation of NA hemadsorption activity among avian virus NAs suggests the maintenance of a required function of NA, loss of the activity does not preclude the replication of the virus in an avian host.

TL;DR: It is reported that a DNA vaccine encoding hemagglutinin from the index human influenza isolate A/HK/156/97 provides immunity against H5N1 infection of mice, and it is determined that unadapted H5n1 viruses are pathogenic in mice, which provides a well-defined mammalian system for immunological studies of lethal avian influenza virus infection.

TL;DR: This finding suggests that the adaptation of NA to different substrates occurs by a mechanism of amino acid substitutions that subtly alter the conformation of NA in and around the active site to facilitate the binding of different species of sialic acid.

TL;DR: It is demonstrated that immunization with DNA encoding a type-specific gene may not be effective against either homologous or heterologous strains of virus, particularly if the challenge virus causes a highly lethal infection.