Intestinal, segmented, filamentous bacteria

Klaasen, H

doi:10.1016/0378-1097(92)90801-t

Cited by 43 publications

(74 citation statements)

References 54 publications

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“…SFB have been found in about 20 vertebrate animals, including humans. and several invertebrate species (10,11). The presence of SFB with characteristic rRNA sequences in chickens, mice, and rats indicates that there has been coevolution of the SFB and their hosts, but comparisons of sequences of SFB from a greater number of animals will be required to confirm this.…”

Section: Discussionmentioning

confidence: 99%

Comparison of 16S rRNA Sequences of Segmented Filamentous Bacteria Isolated from Mice, Rats, and Chickens and Proposal of "Candidatus Arthromitus"

Snel

Heinen²,

Blok³

et al. 1995

International Journal of Systematic Bacteriology

153

122

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Segmented filamentous bacteria (SFB) are nonpathogenic bacteria that are commonly found attached to the intestinal walls of many animals. Until now, these bacteria have not been cultured in vitro. Recently, a 16s rRNA sequence analysis revealed that SFB isolated from mice represent a distinct subline within the Cfostridium subphylum of the gram-positive bacteria. Since SFB isolated from mice, rats, and chickens are known to be host specific, we investigated the phylogenetic relationships among SFB obtained from these three hosts.Total DNAs from the intestinal floras of chickens and rats were used as templates for PCR amplification of 16s rRNA genes. PCR products were cloned and screened by a dot blot hybridization procedure to identify homologous sequences that cross-reacted with mouse SFB-specific oligonucleotide probes. A phylogenetic analysis of these 16s ribosomal DNA sequences revealed that SFB isolated from these three hosts form a natural group, which is peripherally related to the genus Cfostridiurn sensu strict0 (group I Cfostridiurn). The SFB obtained from chickens, rats, and mice had closely related, albeit different, 16s rRNA gene sequences. The observed levels of 16s rRNA sequence divergence, ca. 1.5 to 3%, together with host specificity, suggest that SFB isolated from mice, rats, and chickens represent different species and that coevolution of the SFB and their hosts occurred. "Candidatus Arthromitus" is proposed as the provisional generic name for this group of organisms.The small intestines of many animals (e.g., mice, rats, pigs, and other mammals, as well as chickens, amphibians, and insects) are inhabited by segmented filamentous bacteria (SFB), which are also referred to as long segmented filamentous organisms (reviewed in reference 10). These bacteria cannot be cultured in vitro and do not have official taxonomic names. Until recently, SFB could be recognized only on the basis of their morphology and their ecological niches. In intestines, these gram-positive, endospore-forming organisms are attached via holdfasts to the epithelial walls. In rodents, colonization by SFB is restricted to the ileum (4). In birds, SFB are also found in the ceca (9). No pathologic effects of SFB have been found, even in immunodeficient animals. SFB found in different animal species are morphologically very similar. However, attempts to transfer bacteria from one host species to another have revealed that SFB found in mice, rats, and chickens exhibit host specificity (1, 13, 21). It is not known if SFB that inhabit different hosts are taxonomically closely related or whether they belong to different species.In a recent study, the 16s rRNA-encoding gene sequence of SFB obtained from mice was determined (19). This study was greatly facilitated by the use of a monoculture of these organisms in formerly germfree mice (12). A comparative 16s rRNA * Corresponding author. Mailing address: Central Animal Laboratory, University of Nijmegen, P.O. Box 9101, NL-6500 HB Nijmegen, 'The Netherlands. analysis revealed that th...

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Section: Discussionmentioning

confidence: 99%

Comparison of 16S rRNA Sequences of Segmented Filamentous Bacteria Isolated from Mice, Rats, and Chickens and Proposal of "Candidatus Arthromitus"

Snel

Heinen²,

Blok³

et al. 1995

International Journal of Systematic Bacteriology

153

122

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“…The enrichment of Th17 cells in the ileum of SFB-harboring mice corresponds to an overrepresentation of SFB in that intestinal segment (36,37) and the ability of SFB to form intimate associations with the intestinal epithelium (11). To determine whether B. adolescentis occupied an intestinal niche similar to that of SFB, we measured bacterial titers in various intestinal compartments of mice monocolonized with the former.…”

Section: B Adolescentis Colonizes the Gastrointestinal Tract Widely Andmentioning

confidence: 99%

Identifying species of symbiont bacteria from the human gut that, alone, can induce intestinal Th17 cells in mice

Tan

Sefik

Geva‐Zatorsky

et al. 2016

Proc. Natl. Acad. Sci. U.S.A.

361

287

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Th17 cells accrue in the intestine in response to particular microbes. In rodents, segmented filamentous bacteria (SFB) induce intestinal Th17 cells, but analogously functioning microbes in humans remain undefined. Here, we identified human symbiont bacterial species, in particular Bifidobacterium adolescentis, that could, alone, induce Th17 cells in the murine intestine. Similar to SFB, B. adolescentis was closely associated with the gut epithelium and engendered cognate Th17 cells without attendant inflammation. However, B. adolescentis elicited a transcriptional program clearly distinct from that of SFB, suggesting an alternative mechanism of promoting Th17 cell accumulation. Inoculation of mice with B. adolescentis exacerbated autoimmune arthritis in the K/BxN mouse model. Several off-the-shelf probiotic preparations that include Bifidobacterium strains also drove intestinal Th17 cell accumulation.

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“…A single Gram-positive bacterial species, termed segmented filamentous bacteria (SFB), appears to be primarily responsible for inducing intestinal Th17 cells. This Clostridial-related species is non-culturable, sporulating, and strongly adherent to ileal epithelium and is nearly absent in mice from The Jackson Laboratory (78,79). Inoculation of Jackson mice with fecal microflora from SFB-monocolonized mice potently induces expansion of intestinal IL-17…”

Section: Il-23 and Autoimmunitymentioning

confidence: 99%

Pouring fuel on the fire: Th17 cells, the environment, and autoimmunity

Burkett¹,

Hörste²,

Kuchroo³

2015

J. Clin. Invest.

204

137

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R e v i e w S e R i e S : A u t o i m m u n i t y2 2 1 2 jci.org Volume 125 Number 6 June 2015Murine Th17 differentiation can also be induced in the absence of TGF-β1 signaling, via the combination either of IL-1β, IL-6, and IL-23 or of 42). These TGF-β1-independent Th17 cells can efficiently induce autoimmune tissue inflammation upon adoptive transfer, a trait that led to them being termed "pathogenic" Th17 cells. Additionally, they possess a gene expression profile distinct from that of "nonpathogenic" Th17 cells, which are differentiated with TGF-β1 and IL-6. These observations have led to two competing hypotheses. The first posits that IL-23 cements Th17 lineage commitment such that Th17 cells induced with TGF-β1 and IL-6 are insufficiently committed to the lineage and cannot induce autoimmune tissue inflammation. The second suggests that there are distinct subtypes of Th17 cells whose differentiation is dependent on distinct combinations of cytokines. The latter hypothesis is supported by the finding that pathogenic Th17 cells express higher levels of several Th1 lineage-associated transcripts, such as the transcription factor T-bet and IFN-γ, and have been shown to be derived from IL-17 single producers by fate mapping experiments (43,44). Similarly, an important feature of human Th17 cells, as well as those isolated from inflamed tissues in mouse models of Th17-mediated disease, is that they coproduce IL-17 with other cytokines, leading to distinct functional roles (45)(46)(47). For instance, human Th17 cells that produce both IL-10 and IL-17 preferentially respond to Staphylococcus aureus, while those that produce both IL-17 and IFN-γ recognize Candida albicans, suggesting that distinct pathogens induce distinct subtypes of Th17 cells (40). IL-17/IFN-γ coproducers have been ascribed pathogenic functions in the CNS during EAE; however, it has been difficult to reliably differentiate such cells in vitro. Repeated rounds of in vitro culture in the presence of either Th1-inducing cytokines or IL-23 can induce IL-17/IFN-γ coproducers, albeit at moderate percentages. The transcription factors T-bet, RUNX1, and RUNX3 appear to be important in the acquisition of this phenotype (48,49).Large-scale transcriptional analysis of Th17 differentiation at very high temporal resolution has begun to elucidate the molecular networks that control this process, and is a promising approach to the identification of novel regulatory molecules that control pathogenic Th17 differentiation (50, 51). In fact, Th17 development is controlled induction of this lineage. The combination of TGF-β1 and IL-6 efficiently induces IL-17-producing murine T cells in vitro and highlights the reciprocal relationship between induced Tregs, which are generated by TGF-β1 alone, and Th17 cells (19,20). A series of studies demonstrated that IL-21, a γ c -dependent cytokine, could promote the differentiation of Th17 cells (21-23). In combination with TGF-β, IL-21 induces IL-17 production from naive Th cells and promotes the expression of both RORγt, th...

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Intestinal, segmented, filamentous bacteria

Cited by 43 publications

References 54 publications

Comparison of 16S rRNA Sequences of Segmented Filamentous Bacteria Isolated from Mice, Rats, and Chickens and Proposal of "Candidatus Arthromitus"

Comparison of 16S rRNA Sequences of Segmented Filamentous Bacteria Isolated from Mice, Rats, and Chickens and Proposal of "Candidatus Arthromitus"

Identifying species of symbiont bacteria from the human gut that, alone, can induce intestinal Th17 cells in mice

Pouring fuel on the fire: Th17 cells, the environment, and autoimmunity

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