Protein Therapy Used to Fight Persistent Pathogens

Research undertaken at the Institute of Biosciences and Technology may help fight the growing threat of staph infections. Results are proving that the disease-causing pathogen Staphylococcus aureus is becoming more resistant to drugs.

In the Nov. 18 issue of the Journal of Clinical Investigation, Eric Brown, Ph.D., assistant professor at the institute, explains how the MHC class II Analog Protein, known as Map, interferes with the function of T cells, a patient’s most specific defense against foreign intruders. The Map protein also appears to promote the persistence and survival of the bacterium in infected mice.

Staphylococcus aureus is an opportunistic pathogen that causes persistent and sometimes lethal infections such as sepsis, toxic shock syndrome, food poisoning and severe skin diseases. Staphylococcal infections begin when the organism gains access to host tissues or the adjoining blood supply through breaches in the skin. More than 20 percent of healthy humans are natural carriers of the bacterium; 10 to 20 percent of these carriers harbor multidrug-resistant strains. Statistics show that the frequencies of both community-acquired and hospital-acquired staphylococcal infections are on the rise, however, the stockpile of antibiotics is not evolving at a rate capable of quelling growing numbers.

Determining whether an infection is contained or succeeds in spreading is a complex battle between a patient’s immune system’s defensive cells, and the onslaught of the array of enzymes, toxins and other injurious factors released by the bacterium. During early stages of infection, Staphylococcus aureus expresses proteins that enable it to bind to host tissue, as well as allow colonization. Following establishment within the host, other toxins and enzymes help the staphylococci spread to nearby tissue and begin the colonization process over and over again.

“The T cell-inhibitory properties of the Map protein suggest it may function as a therapeutic agent,” Brown says. “Preliminary data from our laboratory indicates it may prevent contact allergies like poison ivy and may prevent skin graft rejection.”

The Houston-based Institute of Biosciences and Technology is a component of the Texas A&M University Health Science Center.

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©2006 Texas Medical Center

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