Role of peptidoglycan protein in immune response may aid HIV research

A family of proteins that serve as the body's first line of defense against bacterial infections may provide a lifeline for individuals with compromised immune systems, according to researchers at the Indiana University School of Medicine - Northwest.

In the Journal of Biological Chemistry, Roman Dziarski, Ph.D., and Dipika Gupta, Ph.D., propose that the proteins might be used to develop medications that could boost the body's impaired day-to-day response to bacteria in HIV/AIDS patients and others with compromised immune responses. The scientists announced discovery of the protein called PGLYRP - peptidoglycan recognition proteins - earlier this year.

Patients, such as those with HIV/AIDS, are susceptible to bacterial infections that are easily averted by people with healthy immune systems but are life-threatening to people with impaired systems.

Drs. Dziarski and Gupta, in their latest report, revealed many parts of the body produce these proteins, which fight disease-causing bacteria. These proteins appear to be the front line in defending the body from infection, mounting a defense long before the body's main immune system responds.

The IU School of Medicine - Northwest scientists report that various organs mount different defensive responses with PGLYRP when exposed to bacteria. The skin produces these proteins only when exposed to virulent or high numbers of bacteria.

In contrast, the liver, whose function is to continuously monitor the blood and fight acute infection, produces PGLYRP constantly. The researchers suggest that the liver's constant protein production may help fulfill the organ's preventative role as a blood filter.