A Cautionary Tale pg. 2
Illustration of an influenza virus partially cut away to reveal internal structures. The green core contains the genetic information of the virus wrapped up in protein. This combination of genetic material and protein is called the nucleocapsid. Overlying the nucleocapsid is a layer of matrix protein, shown in purple. Over that is the viral envelope (blue-green and edged in yellow) derived from the host cell membrane. The nucleocapsid and the matrix proteins become wrapped in cell membrane as they bud from the infected cell. The characteristic “spikes” of the influenza virus are surface membrane glycoproteins, called haemagglutinin, that are involved in attachment and fusion to the target cell. They radiate all over the surface and are interspersed (in some types) by clusters of neuraminidase, another membrane glycoprotein that enables newly formed virions to bud from infected cells.
These rapidly evolving glycoproteins are part of the reason flu vaccines must be adjusted to the prevailing influenza strains every winter.
Editor's Note: This illustration and for the cover illustration of the Spring 2004 issue were not credited correctly in the print version of the magazine. They are both by Russell Kightley.
Illustration by Russell Kightley. Copyright Russell Kightley Media