Immune Cell Recognition Mechanisms Explained

Whenever a strain of bacteria, a virus or a microbe decide to enter the human body, they immediately subject themselves to the actions of the immune system. With very few exceptions, as in pathogens that are known to be deadly, immune cells manage to destroy all these invaders, by binding to them, consuming them, and then splitting them into their constituent chemicals. In the case of the normal flu, the virus causing the illness travels through the body in the form of a double-stranded RNA molecule, acting like a toxin, and causing negative side-effects.

Some of these include various aches and fever, caused by the toxic effects pathogens have on the body. Microbiologists have known for a long time that eventually the immune system picks up on these chemical trails and that it begins attacking the intruders, but precisely how this response is activated has remained shrouded in mystery for many ears. Recently, experts at the McMaster University managed to discover how a class of proteins, known as class A scavenger receptors, plays a fundamental part in this ability, allowing for many types of cells to pick up double-stranded RNA.

“Since the 1950s and '60s, it's been known that double-stranded RNA is a viral toxin. But what we haven't known is how cells recognize double-stranded RNA outside of the cell. We know how they respond to it. We know they take it up. But we've never appreciated how that happens,” says MU Michael G. DeGroote School of Medicine Department of Pathology and Molecular Medicine associate professor Karen Mossman. The new investigation, which looked at the actions of 5 different types of scavenger receptors, was conducted both on human cells, and on cells harvested from lab mice, PhysOrg reports.

Due to the fact that the receptors have been found expressed ubiquitously around various types of cells, the investigators believe that they may have just found a new target for a host of anti-viral therapies, aimed at a very wide range of diseases. Details of their investigation appear in the March 26 issue of the open-access scientific journal PLoS Pathogens, a publication of the Public Library of Science. “Now that we know what to manipulate, we can start looking at how we can manipulate it to be beneficial during a viral infection. Since all viruses make double-stranded RNA, targeting these receptors should be effective against many different viral infections including influenza and other pandemic viruses,” Mossman concludes.