Scientists explain why Crohn disease is localized to specific regions of the gut

September 02, 2003

Markus Neurath and fellow researchers at the University of Mainz, Germany, have characterized the interaction between intestinal bacteria and dendritic cells (DCs) that may provide an explanation for the clinical symptoms of Crohn disease that only occur in specific regions of the gut.

The authors used transgenic mice to investigate the expression of the p40 subunit of IL-12 and IL-23. The authors demonstrate that p40 is expressed by a newly identified subset of DCs at greater levels in the lower part of the small intestine when compared to the proximal part of the small intestine or the colon.

Neurath and colleagues demonstrate that p40 production is dependent on the intestinal bacteria as germ-free animals do not exhibit elevated p40 expression in the small intestine.

The data reveal important functional differences between the mucosal immune systems of the small and large bowel in healthy mice and suggest that the high numbers of bacteria in the terminal ileum activate p40 expression. The authors suggest that this pattern of p40 expression may explain the predisposition of the terminal ileum to develop chronic inflammation responses via IL-23 and may therefore provide a molecular reason for the preferential clinical manifestation of Crohn disease in this region of the gut.

In an accompanying commentary, Holm Uhlig and Fiona Powrie from the University of Oxford discuss how intestinal DCs sense bacteria in the gut. They also comment that the IL-12 p40 promoter transgenic mice produced by Neurath and coworkers "will be an excellent tool to study the interaction between particular bacteria and the host immune system and how this influences the localization of the immune response".
-end-
TITLE: Constitutive p40 promoter activation and IL-23 production in the terminal ileum mediated by dendritic cells

AUTHOR CONTACT:
Markus F. Neurath,
University of Mainz, Mainz, Germany
Phone: 49-6131-172374
Fax: 49-6131-175508
E-mail: neurath@1-med.klinik.uni-mainz.de
View the PDF of this article at: http://www.jci.org/cgi/content/full/112/5/693.

ACCOMPANYING COMMENTARY:
Dendritic cells and the intestinal bacterial flora: a role for localized mucosal immune responses

AUTHOR CONTACT:
Fiona Powrie
Sir William Dunn School of Pathology, University of Oxford, Oxford, United Kingdom
Phone: 44-1865-285494
Fax: 44-1865-275591
E-mail: fiona.powrie@pathology.ox.ac.uk


JCI Journals

Related Bacteria Articles from Brightsurf:

Siblings can also differ from one another in bacteria
A research team from the University of Tübingen and the German Center for Infection Research (DZIF) is investigating how pathogens influence the immune response of their host with genetic variation.

How bacteria fertilize soya
Soya and clover have their very own fertiliser factories in their roots, where bacteria manufacture ammonium, which is crucial for plant growth.

Bacteria might help other bacteria to tolerate antibiotics better
A new paper by the Dynamical Systems Biology lab at UPF shows that the response by bacteria to antibiotics may depend on other species of bacteria they live with, in such a way that some bacteria may make others more tolerant to antibiotics.

Two-faced bacteria
The gut microbiome, which is a collection of numerous beneficial bacteria species, is key to our overall well-being and good health.

Microcensus in bacteria
Bacillus subtilis can determine proportions of different groups within a mixed population.

Right beneath the skin we all have the same bacteria
In the dermis skin layer, the same bacteria are found across age and gender.

Bacteria must be 'stressed out' to divide
Bacterial cell division is controlled by both enzymatic activity and mechanical forces, which work together to control its timing and location, a new study from EPFL finds.

How bees live with bacteria
More than 90 percent of all bee species are not organized in colonies, but fight their way through life alone.

The bacteria building your baby
Australian researchers have laid to rest a longstanding controversy: is the womb sterile?

Hopping bacteria
Scientists have long known that key models of bacterial movement in real-world conditions are flawed.

Read More: Bacteria News and Bacteria Current Events
Brightsurf.com is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.com.