Have you ever wondered why does the immune system succeed in only fighting against certain viruses and seems incapable of doing so for others? This restricted capability of the immune system may in turn lead to potentially fatal diseases like hepatitis C and HIV. But now a team of experts from UCLA AIDS Institute have attempted to answer this mysterious question. They have stated that the interleukin-21 protein may be credited for the enhanced ability of the cells to fight against viruses. These findings may aid in better understanding the process of the immune system in restricting the replication and spread of the virus.
The interleukin-21 (IL-21) protein is stated to be a robust molecule which is emitted during chronic infection by the immune cells. For this purpose the CD4 T-cells and CD8 T-cells were evaluated. As the name itself suggests they come from the T-cells family. They are immune cells which are considered very crucial in the body’s fight against infections. Supposedly the CD4 T-cells and the immune system together create interleukin-21 during an infection. This in turn seemingly boosts the ability of the CD8 T-cells to fight against viruses.
In order to evaluate this procedure, an analysis was conducted on animal models. The experts were stated to have purposely infected these creatures with two strains of a virus. It was predicted that the first strain may lead to short-term infection while the latter may lead to chronic infection. Each of these two strains were stated to have been tested on two sets of mice, where one group was bred normally while the other was bred without IL-21 receptors.
Lead investigator, David Brooks, assistant professor of microbiology, immunology and molecular genetics, David Geffen School of Medicine, UCLA, says that, “IL-21 fuels CD8 T-cells’ ability to function. These immune cells are running a long-distance race to contain the virus before it spreads. If they don’t get fed, they collapse on the track.”
It was observed that the T-cells depend on the IL-21 protein to resolve the chronic infection. Brooks further says that in the absence of the CD8 T-cells, the immune system may not be able to fight against the viruses. This in itself indicates that interleukin-21 may have a very crucial role to play in the battle against persistent infection in the body.
The study has been presented online in Science.