A study published in Infection and Immunity found that the external capsule of Porphyromonas gingivalis, a bacterium associated with periodontal disease, protects the bacterium from the host’s immune response. The study compared the ability of normal bacteria to mutant bacteria that were missing the capsule to activate the immune system; to enter eukaryotic cells (present in multicellular organisms); to cause disease; and to survive in mice. The study found that the mutant bacteria without the capsule activated the host’s immune system to a greater extent than the normal bacteria with the capsule; thus the mutant bacteria were more easily killed by eukaryotic cells. The study notes that anything that would interfere with generation of the capsule, such as drugs interfering with the action of enzymes involved in synthesis of the sugar coat (the capsule is comprised of sugar molecules), could be used in treating periodontal disease as well as having broader implications for preventing more serious diseases by other encapsulated bacteria.
(Source: ScienceDaily, November 16, 2011, from materials provided by the American Society for Microbiology)
