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Microbial pattern recognition receptors mediate M-cell uptake of a gram-negative bacterium

journal contribution
posted on 06.12.2017, 00:00 by P Tyrer, A Foxwell, A Cripps, M Apicella, Jennelle Kyd
The receptors involved in the sampling of particulate microbial antigens by the gut are largely unknown. Here we demonstrate for the first time in an in vitro M-cell model and in situ in isolated murine intestinal segments that the receptors TLR-4, PAF-R, and α5ß1 integrin are all involved in mediating bacterial uptake associated with transcytosis. The pattern of expression of TLR-4 and α5ß1 integrin differed between M cells and enterocytes. There was increased apical expression of TLR-4 in M-cell cultures, and it was present on the apical surface of murine M cells but not enterocytes in situ. In contrast, PAF-R was expressed equally by both cell types in vitro and was abundantly expressed throughout the intestinal epithelium. Inhibition of TLR-4 and PAF-R, but not TLR-2, reduced gram-negative bacterial uptake by both cell types, whereas inhibition of the apically expressed α5ß1 integrin significantly reduced the ability of M cells to translocate bacteria. Hence, the involvement of each receptor was dependent not only on differences in the level of receptor expression but the cellular localization. Using bacteria that had mutations that affected the bacterial lipooligosaccharide structure indicated that the oligosaccharide moiety was important in bacterial uptake. Taken together, the data suggest that pathogen-associated molecular pattern interactions with pattern recognition receptors are key factors in M-cell recognition of intestinal antigens for mucosal immune priming.

History

Volume

74

Issue

1

Start Page

625

End Page

631

Number of Pages

7

eISSN

1070-6313

ISSN

0019-9567

Location

United States

Publisher

American Society for Microbiology

Language

en-aus

Peer Reviewed

Yes

Open Access

No

Era Eligible

Yes

Journal

Infection and immunity.

Exports

CQUniversity

Exports