<<Disclaimer: Verify this information before applying it to your situation.>> Symbiotic gut bacteria again have been shown to play a significant role in the development of the intestine and its immune function. This time the combination of Bacteroides fragilis and Bacillus subtilis are shown to be required for development of gut-associated lymphoid tissues (GALT). Previously Bacteriodes thetaiotaomicron was shown to be needed for intestinal blood vessel development, gut fructose synthesis, and gut defensive antimicrobial chemical production. This research is absolutely fantastic in its revelation of previously unknown bacteria/gut dependencies. It is becoming increasingly clear that the relationship of commensal bacteria to gut development is of primary importantance and cannot be overlooked as a contributing factor to immunological disorders of the gut (celiac disease included.) I would hope at the upcoming NIH Consensus Conference on Celiac Disease in June it will be acknowledged that serious CD research must be directed to the study of commensal bacteria and CD. ---------- J Immunol. 2004 Jan 15;172(2):1118-24 http://www.jimmunol.org/cgi/content/abstract/172/2/1118 Role of commensal bacteria in development of gut-associated lymphoid tissues and preimmune antibody repertoire. Rhee KJ, Sethupathi P, Driks A, Lanning DK, Knight KL. Department of Microbiology and Immunology, Stritch School of Medicine, Loyola University Chicago, Maywood, IL 60153, USA. Intestinal bacteria are required for development of gut-associated lymphoid tissues (GALT), which mediate a variety of host immune functions, such as mucosal immunity and oral tolerance. In rabbits, the intestinal microflora are also required for developing the preimmune Ab repertoire by promoting somatic diversification of Ig genes in B cells that have migrated to GALT. We studied the mechanism of bacteria-induced GALT development. Bacteria were introduced into rabbits in which the appendix had been rendered germfree by microsurgery (we refer to these rabbits as germfree-appendix rabbits). We then identified specific members of the intestinal flora that promote GALT development. The combination of Bacteroides fragilis and Bacillus subtilis consistently promoted GALT development and led to development of the preimmune Ab repertoire, as shown by an increase in somatic diversification of VDJ-C micro genes in appendix B cells. Neither species alone consistently induced GALT development, nor did Clostridium subterminale, Escherichia coli, or Staphylococcus epidermidis. B. fragilis, which by itself is immunogenic, did not promote GALT development; hence, GALT development in rabbits does not appear to be the result of an Ag- specific immune response. To identify bacterial pathways required for GALT development, we introduced B. fragilis along with stress-response mutants of B. subtilis into germfree-appendix rabbits. We identified two Spo0A- controlled stress responses, sporulation and secretion of the protein YqxM, which are required for GALT development. We conclude that specific members of the commensal, intestinal flora drive GALT development through a specific subset of stress responses. PMID: 14707086 [PubMed - in process] * * * *Support summarization of posts, reply to the SENDER not the CELIAC List*