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Access through your institution Buy or subscribe To look at the regulation of p40 expression, Becker _et al_. created transgenic mice in which the firefly luciferase gene is under the

control of the _p40_ promoter. Various organs from healthy transgenic mice were then analysed for constitutive luciferase expression. High levels of luciferase were detected in Peyer's

patch-free samples of the distal small intestine, but not the proximal part of this organ or the colon. The constitutive activity of the _p40_ promoter in the distal small intestine was

confirmed by showing that this region expresses high levels of p40 protein and also IL-23 (but not IL-12). The cell population producing IL-23 was then identified as CD8α−CD11c+CD11b−

lamina-propria dendritic cells (LPDCs). There was no difference in the number of LPDCs between the proximal and distal regions of the small intestine, so the authors looked for an

alternative explanation for the differential p40 production. Previous studies have shown that the _p40_ promoter can be activated by bacterial products through Toll-like receptor signalling

involving nuclear factor-κB, and mice bred under germ-free conditions did not have increased p40 expression in the distal small intestine, so the intestinal microflora might have some role.

Using an oligonucleotide probe that binds to the ribosomal RNA of all eubacteria, p40 protein was shown to be co-localized with bacteria in LPDCs of the distal intestine. The same probe was

used to show that there is a higher concentration of bacteria in the crypts of the distal intestine than the proximal intestine, and that these bacteria are taken up by LPDCs. This is a

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during checkout ADDITIONAL ACCESS OPTIONS: * Log in * Learn about institutional subscriptions * Read our FAQs * Contact customer support REFERENCES ORIGINAL RESEARCH PAPER * Becker, C. et

al. Constitutive _p40_ promoter activation and IL-23 production in the terminal ileum mediated by dendritic cells. _J. Clin. Invest._ 112, 693–706 (2003) Article  CAS  Google Scholar 

FURTHER READING * Bouma, G. & Strober, W. The immunological and genetic basis of inflammatory bowel disease. _Nature Rev. Immunol._ 3, 521–533 (2003) Article  CAS  Google Scholar  *

Trinchieri, G. Interleukin-12 and the regulation of innate resistance and adaptive immunity. _Nature Rev. Immunol._ 3, 133–146 (2003) Article  CAS  Google Scholar  Download references

Authors * Kirsty Minton View author publications You can also search for this author inPubMed Google Scholar RIGHTS AND PERMISSIONS Reprints and permissions ABOUT THIS ARTICLE CITE THIS

ARTICLE Minton, K. An inflammatory situation. _Nat Rev Immunol_ 3, 773 (2003). https://doi.org/10.1038/nri1217 Download citation * Issue Date: 01 October 2003 * DOI:

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