SAN FRANCISCO, Sept. 19 (Xinhua) -- Researchers at Oregon State University (OSU) have identified a pair of proteins that show promise as the basis for a gonorrhea vaccine.
Published in the Journal of Bacteriology, the findings are a step toward a potential new weapon in the fight against gonorrhea, a sexually transmitted disease that affects millions of people around the globe, with nearly 80 million new cases estimated each year.
Gonorrhea is highly damaging to reproductive and neonatal health if untreated. It can lead to endometritis, pelvic inflammatory disease, ectopic pregnancy, epididymitis and infertility.
In addition, babies born to infected mothers are at increased risk of blindness. The pathogen that causes the disease, Neisseria gonorrhoeae, is considered a "superbug" because of its resistance to all classes of antibiotics available for treating infections.
Subjecting N. gonorrhoeae to the phenotypic microarray screening method for the first time, the team led by OSU College of Pharmacy researcher Aleksandra Sikora focused on seven proteins from the bacteria's cell envelope, which consists of the outer membrane, the cell wall and the inner membrane.
The goal was to see which if any of the seven proteins would show strong potential as a vaccine antigen, namely a molecule that sends the immune system into action against the pathogen.
While more than 1,000 conditions were used to study the effects of knocking out each of the seven proteins, the researchers found 91 conditions that had uniquely positive or negative effects on one of the mutants, and a cluster analysis of 37 commonly beneficial compounds and 57 commonly detrimental compounds revealed three separate phenotype groups.
"Neisseria gonorrhoeae is a difficult bacteria to work with," Sikora noted in an OSU news release Tuesday. "It has great genome plasticity - there are huge variations between strains. Phenotypic screening allows us to see how similar and how different they are."
Two of the proteins, NGO1985 and NGO2121, showed extensive sensitivity to antimicrobial compounds and thus emerged as the most promising vaccine candidates.
Designed by Sikora and supported by the U.S. National Institutes of Health (NIH), the study serves as a jumping-off point for further characterization of proteins in the cell envelope.