Researchers at the University of Pittsburgh School of Medicine in collaboration with the Centers for Disease Control and Prevention (CDC) have developed a vaccine against the deadly H5N1 subtype of Avian Influenza which was protective when tested in mice and chickens. The H5N1 virus has resulted in the death or destruction of 150 to 200 million birds since it first appeared in the late 1990’s in several southeast Asian countries, and most recently in Turkey and Romania. There have been more than 170 confirmed human cases resulting in more than 80 deaths.
The vaccine virus, produced in cell culture, is genetically engineered using an adenovirus vector to present the avian influenza hemagglutinin protein (HA) on its surface. HA is important for attachment of the influenza virus to the host cell. The researchers have experimented with various vaccines containing either the full HA sequence or HA subunits. When compared to animals vaccinated with adenovirus vectors containing no H5N1 genes, animals vaccinated with either subunit or whole sequence vaccines exhibited milder disease and a strong cellular immune response. The whole sequence vaccines exhibited the most protection inducing both antibody and T cell-directed immunity.
The recombinant vaccine development approach allows for more rapid production of vaccine compared to the traditional technique using fertilized chicken eggs which could be in short supply should there be a global pandemic of avian influenza. Growing vaccine virus in cell culture would shorten production time from several months to a little over one month. The researchers are planning a small clinical trial in humans to begin soon.
Source:
UPMC