Gingivitis bacteria found to manipulate immune system

0 23 October 2014

BIRMINGHAM, Ala., USA: New research from the U.S. provides evidence that Porphyromonas gingivalis, the main agent of the chronic inflammatory disease periodontitis, also manipulates the human immune system. In a number of laboratory tests, scientists observed that the pathogen inhibits the body’s defense processes that would normally destroy it. In order to determine the manner in which P. gingivalis influences the immune system, the researchers treated cells from mice with an inhibiting antibody against Interleukin-10 (IL-10), an anti-inflammatory protein, while leaving a different portion of the same cells untreated. Afterwards, they tested whether the cells produced interferon-gamma (IFN-γ), a protein that has an immunostimulatory and antiviral effect. According to the study, P. gingivalis stimulated the production of IL-10, which in turn inhibited the activity of T-cells and macrophages, and repressed the immune response. The researchers observed increased production of IFN-γ in the treated cells, while no such growth was seen in the untreated cells. The study highlighted the mechanism by which the pathogen establishes a chronic infection. “These bacteria go beyond merely evading our body’s defense and actually manipulate our immune system for their own survival,” the researchers said. The findings suggested that the damage done by the bacterium occurs when the immune cel

0 23 October 2014

COLUMBUS, Ohio, USA: Microbiologists have suggested that bacteria present in the oral cavity are a reliable indicator of a person’s ethnicity. In a study of participants from four different ethnic groups, they found that each group had an individual set of oral microbes. They believe that these microbes might also predispose individuals to certain oral diseases. The study included 192 healthy individuals aged 18 and over who consisted of non-Hispanic blacks, non-Hispanic whites, Chinese people and Latinos. Researchers at the Ohio State University compared the oral microbial communities they obtained from bacterial samples from the participants’ saliva, tooth surfaces and gums after sequencing their DNA. Using a special machine, they were able to predict an individual’s ethnicity with 62 percent accuracy based on a given bacterial community. African-Americans were correctly identified according to their microbial signature 100 percent of the time. Latinos were identified with 67 percent accuracy and Caucasians with 50 percent. The classifying machine performed best when subgingival microbes were used. This was attributed to the fact that these bacteria are the least likely to be disrupted by environmental changes in the mouth, such as food, toothpaste and tobacco. Overall, they found 398 species, with an average of about 150 species per person. Only 2 percent were present in all