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From:
Roy Jamron <[log in to unmask]>
Reply To:
Roy Jamron <[log in to unmask]>
Date:
Tue, 3 Feb 2004 23:32:08 -0500
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<<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.

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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]

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