Open AccessAdherent‐invasive Escherichia coli isolated from Crohn's disease patients induce granulomas in vitro
Author(s) -
Meconi Sonia,
Vercellone Alain,
Levillain Florence,
Payré Bruno,
Al Saati Talal,
Capilla Florence,
Desreumaux Pierre,
DarfeuilleMichaud Arlette,
Altare Frédéric
Publication year - 2007
Publication title -
cellular microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.542
H-Index - 138
eISSN - 1462-5822
pISSN - 1462-5814
DOI - 10.1111/j.1462-5822.2006.00868.x
Subject(s) - biology , giant cell , granuloma , epithelioid cell , microbiology and biotechnology , in vitro , escherichia coli , peripheral blood mononuclear cell , pathology , immunology , immunohistochemistry , biochemistry , genetics , gene , medicine
Summary Adherent‐invasive Escherichia coli (AIEC) have been shown to be highly associated with ileal Crohn's disease (CD). AIEC survive within infected macrophages, residing within the phagolysosomal compartment where they take advantage of the low pH to replicate extensively. We investigated whether, like the tuberculous bacillus which also persists within macrophages, AIEC LF82 induces the formation of granulomas, which are a common histopathological feature of CD. For this purpose, we have taken advantage of an in vitro model of human granulomas that we recently developed, based on blood‐derived mononuclear cells. We demonstrated that AIEC LF82 induces aggregation of infected macrophages, fusion of some of them to form multinucleated giant cells and subsequent recruitment of lymphocytes. Light microscopy and scanning electron microscopy analysis of the cell aggregates confirmed their granuloma features. This was further confirmed by histological analysis of granuloma sections. Noteworthy, this phenomenon can be reproduced by soluble protein extracts of AIEC LF82 coated onto beads. Although the cell aggregates not completely mimic natural CD‐associated granulomas, they are very similar to early stages of epithelioid granulomas.