Commensal gut bacteria: mechanisms of immune modulation

Kelly, Denise; Conway, Shaun; Aminov, Rustam

doi:10.1016/j.it.2005.04.008

Cited by 328 publications

(237 citation statements)

References 90 publications

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“…These bacteria play an important role in health and disease through their involvement in nutrition, pathogenesis and immunology of the host (Gibson and Roberfroid, 1995;Noverr and Huffnagle, 2004;Kelly et al, 2005;Gill et al, 2006). Traditionally, cultivation-based techniques have been used to determine the bacterial composition in faeces.…”

Section: Introductionmentioning

confidence: 99%

Long-term ecological impacts of antibiotic administration on the human intestinal microbiota

et al. 2007

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Antibiotic administration is known to cause short-term disturbances in the microbiota of the human gastrointestinal tract, but the potential long-term consequences have not been well studied. The aims of this study were to analyse the long-term impact of a 7-day clindamycin treatment on the faecal microbiota and to simultaneously monitor the ecological stability of the microbiota in a control group as a baseline for reference. Faecal samples from four clindamycin-exposed and four control subjects were collected at nine different time points over 2 years. Using a polyphasic approach, we observed highly significant disturbances in the bacterial community that persisted throughout the sampling period. In particular, a sharp decline in the clonal diversity of Bacteroides isolates, as assessed by repetitive sequence-based PCR (rep-PCR) and long-term persistence of highly resistant clones were found as a direct response to the antibiotic exposure. The Bacteroides community never returned to its original composition during the study period as assessed using the molecular fingerprinting technique, terminal restriction fragment length polymorphism (T-RFLP). Furthermore, using real-time PCR we found a dramatic and persistent increase in levels of specific resistance genes in DNA extracted from the faeces after clindamycin administration. The temporal variations in the microbiota of the control group were minor compared to the large and persistent shift seen in the exposed group. These results demonstrate that long after the selection pressure from a short antibiotic exposure has been removed, there are still persistent long term impacts on the human intestinal microbiota that remain for up to 2 years post-treatment.

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Section: Introductionmentioning

confidence: 99%

Long-term ecological impacts of antibiotic administration on the human intestinal microbiota

et al. 2007

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“…For gut bacteria, surface proteins are the prime contact point of the bacterial cell with the host. They possess key functions in the adaptation to the gastrointestinal environment, as well as in the colonization of host tissues, and in the induction of host downstream responses (Kelly et al, 2005a;Marco et al, 2006). In bifidobacteria, claims have been made regarding, for instance, cell-surface proteinaceous components involved in intestinal adhesion (Mukai et al, 2004), proteinaceous factor(s) in culture supernatant fluids of bifidobacteria which prevent(s) the binding of enterotoxigenic Escherichia coli (Fujiwara et al, 1997), or supernatants of Bifidobacterium breve that can modulate transduction signalling pathways and induce maturation in human dendritic cells (Hoarau et al, 2006(Hoarau et al, , 2008.…”

Section: Discussionmentioning

confidence: 99%

The cell-envelope proteome of Bifidobacterium longum in an in vitro bile environment

et al. 2009

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Host-bacteria interactions are often mediated via surface-associated proteins. The identification of these proteins is an important goal of bacterial proteomics. To address how bile can influence the cell-envelope proteome of Bifidobacterium longum biotype longum NCIMB 8809, we analysed its membrane protein fraction using stable isotope labelling of amino acids in cell culture (SILAC). We were able to identify 141 proteins in the membrane fraction, including a large percentage of the theoretical transporters of this species. Moreover, the envelope-associated soluble fraction was analysed using different subfractionation techniques and differential in-gel fluorescence electrophoresis (DIGE). This approach identified 128 different proteins. Some of them were well-known cell wall proteins, but others were highly conserved cytoplasmic proteins probably displaying a 'moonlighting' function. We were able to identify 11 proteins in the membrane fraction and 6 proteins in the envelope-associated soluble fraction whose concentration varied in the presence of bile. Bile promoted changes in the levels of proteins with important biological functions, such as some ribosomal proteins and enolase. Also, oligopeptide-binding proteins were accumulated on the cell surface, which was reflected in a different tripeptide transport rate in the cells grown with bile. The data reported here will provide the first cell-envelope proteome map for B. longum, and may contribute to understanding the bile tolerance of these bacteria

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“…The microbiota have a powerful impact on the mucosal immune system [15][16][17]. Multiple species of non-pathogenic bacteria can attenuate the NF-kB pathway via inhibition of IkB-a ubiquitination or by regulating the nuclear export of NF-kB [18][19][20].…”

Section: Introductionmentioning

confidence: 99%

Curcumin induces the tolerogenic dendritic cell that promotes differentiation of intestine‐protective regulatory T cells

Cong¹,

Wang²,

Konrad³

et al. 2009

Eur J Immunol

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The gut is home to a large number of Treg, with both CD4 1 CD25 1 Treg and bacterial antigen-specific Tr1 cells present in normal mouse intestinal lamina propria. It has been shown recently that intestinal mucosal DC are able to induce Foxp3 1 Treg through production of TGF-b plus retinoic acid (RA). However, the factors instructing DC toward this mucosal phenotype are currently unknown. Curcumin has been shown to possess a number of biologic activities including the inhibition of NF-jB signaling. We asked whether curcumin could modulate DC to be tolerogenic whose function could mimic mucosal DC. We report here that curcumin modulated BM-derived DC to express ALDH1a and IL-10. These curcumin-treated DC induced differentiation of naïve CD4 1 T cells into Treg resembling Treg in the intestine, including both CD4 1 CD25 1 Foxp3 1 Treg and IL-10-producing Tr1 cells. Such Treg induction required IL-10, TGF-b and retinoic acid produced by curcumin-modulated DC. Cell contact as well as IL-10 and TGF-b production were involved in the function of such induced Treg. More importantly, these Treg inhibited antigen-specific T-cell activation in vitro and inhibited colitis due to antigen-specific pathogenic T cells in vivo.

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Commensal gut bacteria: mechanisms of immune modulation

Cited by 328 publications

References 90 publications

Long-term ecological impacts of antibiotic administration on the human intestinal microbiota

Long-term ecological impacts of antibiotic administration on the human intestinal microbiota

The cell-envelope proteome of Bifidobacterium longum in an in vitro bile environment

Curcumin induces the tolerogenic dendritic cell that promotes differentiation of intestine‐protective regulatory T cells

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