Antibodies constitute one of the most effective defensive mechanisms of the organism against pathogens. Still, one of these proteins facilitates the occurrence of permanent intestinal colonisation by certain bacteria - which also affects health.
Bacteroidesfragilis uses immunoglobulin A (IgA), namely one of the most common antibodies present within the organism. The antibody restores the surface of a bacterium, thus helping it adhere to the intestinal mucosal surface and become a stable part of the microbiota. The finding was observed in mice and it may facilitate the treatment of various disease conditions through the supplementation of the human organism with selected micro-organisms.
"The exploitation of the immune system by bacteria affects the functioning of many physiological processes of the organism", says Sidonia Fagarasan, an immunologist at the RIKEN Yokohama Institute in Japan.
IgA was discovered 50 years ago. Each human produces between 3 and 5 grams of it a day, making up approximately 75% of production of all antibodies that are present within the organism. IgA is also present in mother's milk, while it has not been observed until now that a low level of these immunoglobulins is additionally coupled with one's abnormal gut-microflora. It was yet difficult to provide an explanation why, while the microbiologists Sarkis Mazamanian and Gregory Donaldson of the California Institute of Technology in Pasadena have used a combination of immunological, microbiological, genetic and imaging techniques, as well as they noticed that IgA antibodies affect the clustering of pathogens along the intestinal lining or their spread through the protective layer of mucus. Consequently, they participate in the preservation of gastrointestinal microflora in the right condition. It means that the same molecule of the immune system may affect different microorganisms in a variety of ways - while it can destroy some, it can also help others survive. This relation is to become used in many long-term clinical applications from now on.
Source: science mag.org