α1-3Gal antigen in gut microbiota, a potential new environmental factor in multiple sclerosis

Abstract Gut microbiota from multiple sclerosis (MS) patients present qualitative and quantitative differences of bacteria abundance compared to healthy subjects. In an another hand, gut microbiota may drive some specific types of antibody responses in human and may represent a new environmental factor in MS etiology. However, whether and to which extent the amount of a given microbiota antigen is associated with the level of the antibody response against the corresponding antigen is yet unknown. The level of anti-α1-3Gal (Gal) antibodies are decreased in MS. Recently, we have proposed a first map of gut bacteria displaying α1-3-Galactosyltransferase gene sequences. This review summarizes the current knowledge on antibody response to the Gal epitope associated to changes of gut microbiota profile in MS as well as on the possible mechanisms by which the altered microbiota and/or circulating anti-Gal level could affect the immune response in this disease.