Microbe-induced antibody responses against dietary plant glycans 3886

Abstract Description Protein and glycan antigens on gut microbial surfaces stimulate the production of circulating and secreted antibodies in mammals. Despite the high abundance of plant glycans (derived from dietary fiber) in the intestine, it remains unclear whether these foreign structures also serve as B-cell antigens. We screened for antibodies that bind diverse dietary fibers using a panel of artificial food particles consisting of microscopic magnetic beads, each simultaneously tagged with a fluorescent barcode and coated with a different dietary glycan preparation. We observed circulating fiber-specific antibodies that were significantly reduced when mice were deprived of fiber for multiple generations. Furthermore, fiber supplementation added to a normal chow diet induced glycan specific antibodies that were independent of T-cells. Germ-free and monocolonized mice failed to exhibit fiber-induced antibody responses, demonstrating that microbial stimulation is required. However, transient antibiotic treatment had no effect on antibody induction during fiber supplementation, implicating microbial sensitization prior to fiber feeding. We stained mouse gut microbes with a library of glycan-specific monoclonal antibodies and identified bacteria whose surfaces mimic commonly consumed dietary plant glycans. Our results raise the possibility that contact with gut microbes whose surfaces resemble dietary plants sensitizes the host to subsequent dietary exposures. Funding Sources NIH GM150732 Topic Categories Mucosal and Regional Immunology (MUC)