Viruses are complex and efficient organisms that are able to survive within a host despite the intense natural selection pressures that are exerted upon them.  Such survival is due to the complex and efficient functioning of a virus as it readily adapts and evolves within its host; rapidly mutating, continually reproducing and all the while skillfully evading detection by the immune system.

The continuous evolutionary processes of a virus are not without record. This rapid ability to evolve combined with the ability to acquire genes from its host enables the virus to generate proteins called “virulence factors” that down regulate the immune response. These genes’ products provide an enormous selective advantage to the survival of the virus.

It is the viral evolutionary process that provides VLST with an accurate indicator of cellular targets important to modulate the human immune system.  Whatever a virus targets in its host is validated as an important immunomodulatory target.  Whatever form the virus has evolved into, the viral protein that binds that target is the form that will be the most efficient.  Virulence factors thus provide an important and validated method for the identification of cellular targets with potential to affect the immune system. This same scientific approach was used in the validation of the human TNF receptor as a therapeutic target and in the molecular design of Enbrel® an Amgen product, which enjoys worldwide annual sales in excess of $3 billion.