RESUMEN
The role of plasmids in the complex pandemic of antimicrobial resistance is increasingly being recognized. In this respect, multiple mobile colistin resistance (mcr) gene-carrying plasmids have been described. However, the characteristics and epidemiology of these plasmids within local healthcare settings are largely unknown. We retrospectively characterized the genetic composition and epidemiology of plasmids from mcr-1-positive bacterial isolates identified from patients from a large academic hospital in the Netherlands. Clinical Gram-negative bacteria with an MIC > 2 µg/mL for colistin, obtained from patients hospitalized at the Erasmus MC University Medical Center Rotterdam during the years 2010-2018, were screened for presence of the mcr-1 gene. Extracted plasmids from mcr-1-positive isolates were sequenced using a combination of short- and long-read sequencing platforms, characterized by incompatibility type and genetic composition and compared to publicly available mcr-1-carrying plasmid sequences. In 21 isolates from 14 patients, mcr-1 was located on a plasmid. These plasmids were of diverse genetic background involving Inc types IncX4, IncI2(delta), IncHI2, as well as double Inc types IncHI2/IncN and IncHI2/IncQ. mcr-1-carrying plasmids were found in Escherichia coli, Klebsiella pneumoniae, and Kluyvera georgiana, and within the chromosome of an ST147 K. pneumoniae isolate. In depth analysis indicated intrapatient, interpatient, and interspecies transmission events of mcr-1-carrying plasmids. In addition, our results show that the mcr-1 gene resides in a rich environment full of other (mcr-1 negative) plasmids and of many different Inc types, enabling interplasmidal transfer events and facilitating widespread dissemination of the mcr-1 gene. Multiple mcr-1-carrying plasmid transmission events had likely occurred among isolates from hospitalized patients. Recognition and identification of plasmid transmission events within hospitals is necessary in order to design and implement effective infection control measures.
RESUMEN
Lower respiratory tract infections (LRTIs) in children are common and, although often mild, a major cause of mortality and hospitalization. Recently, the respiratory microbiome has been associated with both susceptibility and severity of LRTI. In this current study, we combined respiratory microbiome, viral, and clinical data to find associations with the severity of LRTI. Nasopharyngeal aspirates of children aged one month to five years included in the STRAP study (Study to Reduce Antibiotic prescription in childhood Pneumonia), who presented at the emergency department (ED) with fever and cough or dyspnea, were sequenced with nanopore 16S-rRNA gene sequencing and subsequently analyzed with hierarchical clustering to identify respiratory microbiome profiles. Samples were also tested using a panel of 15 respiratory viruses and Mycoplasma pneumoniae, which were analyzed in two groups, according to their reported virulence. The primary outcome was hospitalization, as measure of disease severity. Nasopharyngeal samples were isolated from a total of 167 children. After quality filtering, microbiome results were available for 54 children and virology panels for 158 children. Six distinct genus-dominant microbiome profiles were identified, with Haemophilus-, Moraxella-, and Streptococcus-dominant profiles being the most prevalent. However, these profiles were not found to be significantly associated with hospitalization. At least one virus was detected in 139 (88%) children, of whom 32.4% had co-infections with multiple viruses. Viral co-infections were common for adenovirus, bocavirus, and enterovirus, and uncommon for human metapneumovirus (hMPV) and influenza A virus. The detection of enteroviruses was negatively associated with hospitalization. Virulence groups were not significantly associated with hospitalization. Our data underlines high detection rates and co-infection of viruses in children with respiratory symptoms and confirms the predominant presence of Haemophilus-, Streptococcus-, and Moraxella-dominant profiles in a symptomatic pediatric population at the ED. However, we could not assess significant associations between microbiome profiles and disease severity measures.
RESUMEN
BACKGROUND: Bacterial plasmids often carry antibiotic resistance genes and are a significant factor in the spread of antibiotic resistance. The ability to completely assemble plasmid sequences would facilitate the localization of antibiotic resistance genes, the identification of genes that promote plasmid transmission and the accurate tracking of plasmid mobility. However, the complete assembly of plasmid sequences using the currently most widely used sequencing platform (Illumina-based sequencing) is restricted due to the generation of short sequence lengths. The long-read Oxford Nanopore Technologies (ONT) sequencing platform overcomes this limitation. Still, the assembly of plasmid sequence data remains challenging due to software incompatibility with long-reads and the error rate generated using ONT sequencing. Bioinformatics pipelines have been developed for ONT-generated sequencing but require computational skills that frequently are beyond the abilities of scientific researchers. To overcome this challenge, the authors developed 'WeFaceNano', a user-friendly Web interFace for rapid assembly and analysis of plasmid DNA sequences generated using the ONT platform. WeFaceNano includes: a read statistics report; two assemblers (Miniasm and Flye); BLAST searching; the detection of antibiotic resistance- and replicon genes and several plasmid visualizations. A user-friendly interface displays the main features of WeFaceNano and gives access to the analysis tools. RESULTS: Publicly available ONT sequence data of 21 plasmids were used to validate WeFaceNano, with plasmid assemblages and anti-microbial resistance gene detection being concordant with the published results. Interestingly, the "Flye" assembler with "meta" settings generated the most complete plasmids. CONCLUSIONS: WeFaceNano is a user-friendly open-source software pipeline suitable for accurate plasmid assembly and the detection of anti-microbial resistance genes in (clinical) samples where multiple plasmids can be present.
Asunto(s)
Bacterias/genética , Anotación de Secuencia Molecular/métodos , Plásmidos/genética , Programas Informáticos , Bacterias/clasificación , Bacterias/efectos de los fármacos , Bacterias/aislamiento & purificación , Proteínas Bacterianas/genética , Biología Computacional/instrumentación , Biología Computacional/métodos , Farmacorresistencia Bacteriana , Secuenciación de Nucleótidos de Alto RendimientoRESUMEN
BACKGROUND: Long-read sequencing can be applied to generate very long contigs and even completely assembled genomes at relatively low cost and with minimal sample preparation. As a result, long-read sequencing platforms are becoming more popular. In this respect, the Oxford Nanopore Technologies-based long-read sequencing "nanopore" platform is becoming a widely used tool with a broad range of applications and end-users. However, the need to explore and manipulate the complex data generated by long-read sequencing platforms necessitates accompanying specialized bioinformatics platforms and tools to process the long-read data correctly. Importantly, such tools should additionally help democratize bioinformatics analysis by enabling easy access and ease-of-use solutions for researchers. RESULTS: The Galaxy platform provides a user-friendly interface to computational command line-based tools, handles the software dependencies, and provides refined workflows. The users do not have to possess programming experience or extended computer skills. The interface enables researchers to perform powerful bioinformatics analysis, including the assembly and analysis of short- or long-read sequence data. The newly developed "NanoGalaxy" is a Galaxy-based toolkit for analysing long-read sequencing data, which is suitable for diverse applications, including de novo genome assembly from genomic, metagenomic, and plasmid sequence reads. CONCLUSIONS: A range of best-practice tools and workflows for long-read sequence genome assembly has been integrated into a NanoGalaxy platform to facilitate easy access and use of bioinformatics tools for researchers. NanoGalaxy is freely available at the European Galaxy server https://nanopore.usegalaxy.eu with supporting self-learning training material available at https://training.galaxyproject.org.
Asunto(s)
Secuenciación de Nanoporos , Nanoporos , Análisis de Datos , Secuenciación de Nucleótidos de Alto Rendimiento , Análisis de Secuencia de ADN , Programas InformáticosRESUMEN
Illumina and nanopore sequencing technologies are powerful tools that can be used to determine the bacterial composition of complex microbial communities. In this study, we compared nasal microbiota results at genus level using both Illumina and nanopore 16S rRNA gene sequencing. We also monitored the progression of nanopore sequencing in the accurate identification of species, using pure, single species cultures, and evaluated the performance of the nanopore EPI2ME 16S data analysis pipeline. Fifty-nine nasal swabs were sequenced using Illumina MiSeq and Oxford Nanopore 16S rRNA gene sequencing technologies. In addition, five pure cultures of relevant bacterial species were sequenced with the nanopore sequencing technology. The Illumina MiSeq sequence data were processed using bioinformatics modules present in the Mothur software package. Albacore and Guppy base calling, a workflow in nanopore EPI2ME (Oxford Nanopore Technologies-ONT, Oxford, UK) and an in-house developed bioinformatics script were used to analyze the nanopore data. At genus level, similar bacterial diversity profiles were found, and five main and established genera were identified by both platforms. However, probably due to mismatching of the nanopore sequence primers, the nanopore sequencing platform identified Corynebacterium in much lower abundance compared to Illumina sequencing. Further, when using default settings in the EPI2ME workflow, almost all sequence reads that seem to belong to the bacterial genus Dolosigranulum and a considerable part to the genus Haemophilus were only identified at family level. Nanopore sequencing of single species cultures demonstrated at least 88% accurate identification of the species at genus and species level for 4/5 strains tested, including improvements in accurate sequence read identification when the basecaller Guppy and Albacore, and when flowcell versions R9.4 (Oxford Nanopore Technologies-ONT, Oxford, UK) and R9.2 (Oxford Nanopore Technologies-ONT, Oxford, UK) were compared. In conclusion, the current study shows that the nanopore sequencing platform is comparable with the Illumina platform in detection bacterial genera of the nasal microbiota, but the nanopore platform does have problems in detecting bacteria within the genus Corynebacterium. Although advances are being made, thorough validation of the nanopore platform is still recommendable.
Asunto(s)
Genes de ARNr/genética , Secuenciación de Nucleótidos de Alto Rendimiento/métodos , Microbiota/genética , Secuenciación de Nanoporos/métodos , Cavidad Nasal/microbiología , ARN Ribosómico 16S/genética , Adolescente , Adulto , Anciano , Niño , Preescolar , Biología Computacional/métodos , Cartilla de ADN/genética , ADN Bacteriano/genética , Femenino , Humanos , Lactante , Masculino , Persona de Mediana Edad , Nanoporos , Adulto JovenRESUMEN
OBJECTIVE: Previous studies have associated Guillain-Barré syndrome (GBS) with Zika virus (ZIKV) outbreaks in South America and Oceania. In Asia, ZIKV is known to circulate widely, but the association with Guillain-Barré syndrome is unclear. We investigated whether endemic ZIKV infection is associated with the development of GBS. METHODS: A prospective study was conducted from 2011 to 2015 in Bangladesh. A total of 418 patients and 418 healthy family controls were included in the study. Patients were diagnosed with GBS prior to inclusion according to established criteria. Detailed information on the epidemiology, clinical presentation, electrophysiology, diagnosis, disease severity, and clinical course were obtained during a follow-up of 1 year using a predefined protocol. RESULTS: ZIKV-neutralizing antibodies were detected in our study from 2013 onwards. The prevalence of ZIKV-neutralizing antibodies was not significantly higher in patients with GBS compared to healthy controls (OR 2.23, P = 0.14, 95% CI 0.77-6.53). Serological evidence for prior ZIKV infection in patients with GBS was associated with more frequent cranial, sensory, and autonomic nerve involvement compared to GBS patients with Campylobacter jejuni, the predominant preceding infection in GBS worldwide. Nerve-conduction studies revealed that ZIKV antibodies were associated with a demyelinating subtype of GBS, while C. jejuni infections were related to an axonal subtype. INTERPRETATION: No significant association was found between ZIKV infection and GBS in Bangladesh, but GBS following ZIKV infection was characterized by a distinct clinical and electrophysiological subtype compared to C. jejuni infection. These findings indicate that ZIKV may precede a specific GBS subtype but the risk is low.
RESUMEN
Campylobacter jejuni subsp. jejuni infections are a leading cause of foodborne gastroenteritis and the most prevalent antecedent to Guillain-Barré syndrome (GBS). Penner serotype HS:19 is among several capsular types shown to be markers for GBS. This study describes the genome of C. jejuni subsp. jejuni HS:19 Penner reference strain RM3420.
RESUMEN
Poultry products serve as the main source of Campylobacter jejuni subsp. jejuni infections in humans. C. jejuni subsp. jejuni infections are a leading cause of foodborne gastroenteritis and are a prevalent antecedent to Guillain-Barré syndrome. This study describes the genome of C. jejuni subsp. jejuni HS:19 strain RM1285, isolated from packaged chicken in California.
RESUMEN
Although IL-10 promotes a regulatory phenotype of CD11c+ dendritic cells and macrophages in vitro, the role of IL-10 signaling in CD11c+ cells to maintain intestinal tolerance in vivo remains elusive. To this aim, we generated mice with a CD11c-specific deletion of the IL-10 receptor alpha (Cd11ccreIl10rafl/fl). In contrast to the colon, the small intestine of Cd11ccreIl10rafl/fl mice exhibited spontaneous crypt hyperplasia, increased numbers of intraepithelial lymphocytes and lamina propria T cells, associated with elevated levels of T cell-derived IFNγ and IL-17A. Whereas naive mucosal T-cell priming was not affected and oral tolerance to ovalbumin was intact, augmented T-cell function in the lamina propria was associated with elevated numbers of locally dividing T cells, expression of T-cell attracting chemokines and reduced T-cell apoptosis. Upon stimulation, intestinal IL-10Rα deficient CD11c+ cells exhibited increased activation associated with enhanced IL-6 and TNFα production. Following colonization with Helicobacter hepaticus Cd11ccreIl10rafl/fl mice developed severe large intestinal inflammation characterized by infiltrating T cells and increased levels of Il17a, Ifng, and Il12p40. Altogether these findings demonstrate a critical role of IL-10 signaling in CD11c+ cells to control small intestinal immune homeostasis by limiting reactivation of local memory T cells and to protect against Helicobacter hepaticus-induced colitis.
Asunto(s)
Antígeno CD11c/metabolismo , Colitis/prevención & control , Infecciones por Helicobacter/prevención & control , Inmunidad Mucosa , Interleucina-10/metabolismo , Mucosa Intestinal/metabolismo , Intestino Grueso/metabolismo , Intestino Delgado/metabolismo , Linfocitos T/metabolismo , Animales , Antígeno CD11c/deficiencia , Antígeno CD11c/genética , Antígeno CD11c/inmunología , Colitis/inmunología , Colitis/metabolismo , Colitis/microbiología , Modelos Animales de Enfermedad , Predisposición Genética a la Enfermedad , Infecciones por Helicobacter/inmunología , Infecciones por Helicobacter/metabolismo , Infecciones por Helicobacter/microbiología , Helicobacter hepaticus/inmunología , Helicobacter hepaticus/patogenicidad , Homeostasis , Memoria Inmunológica , Interferón gamma/inmunología , Interferón gamma/metabolismo , Interleucina-10/inmunología , Subunidad alfa del Receptor de Interleucina-10/genética , Subunidad alfa del Receptor de Interleucina-10/inmunología , Subunidad alfa del Receptor de Interleucina-10/metabolismo , Interleucina-17/inmunología , Interleucina-17/metabolismo , Mucosa Intestinal/inmunología , Mucosa Intestinal/microbiología , Intestino Grueso/inmunología , Intestino Grueso/microbiología , Intestino Delgado/inmunología , Intestino Delgado/microbiología , Ratones Endogámicos C57BL , Ratones Noqueados , Fenotipo , Transducción de Señal , Linfocitos T/inmunología , Linfocitos T/microbiologíaRESUMEN
Infections with Campylobacter jejuni subsp. jejuni are a leading cause of foodborne gastroenteritis and the most prevalent infection preceding Guillain-Barré syndrome (GBS). This study describes the genomes of C. jejuni subsp. jejuni HS:41 strains RM3196 (233.94) and RM3197 (308.95) that were isolated from patients with GBS in Cape Town, South Africa.
RESUMEN
Molecular mimicry between Campylobacter jejuni sialylated lipooligosaccharides (LOS) and human nerve gangliosides can trigger the production of cross-reactive antibodies which induce Guillain-Barré syndrome (GBS). To better understand the immune events leading to GBS, it is essential to know how sialylated LOS are recognized by the immune system. Here, we show that GBS-associated C. jejuni strains bind to human sialoadhesin (hSn), a conserved, mainly macrophage-restricted I-type lectin. Using hSn-transduced THP-1 cells, we observed that C. jejuni strains with α(2,3)-sialylated LOS, including strains expressing GM1a- and GD1a-like epitopes, bind to hSn. This observation is of importance, as these epitopes are frequently the targets of the cross-reactive antibodies detected in GBS patients. Interestingly, the Sn binding domains were not constitutively exposed on the surface of C. jejuni. Heat inactivation and the environmental conditions which food-borne C. jejuni encounters during its passage through the intestinal tract, such as low pH and contact with bile constituents, exposed LOS and facilitated Sn binding. Sn binding enhanced bacterial uptake and increased the production of interleukin-6 (IL-6) by primary human Sn-expressing monocyte-derived macrophages compared to control conditions, where Sn was blocked using neutralizing antibodies or when nonsialylated C. jejuni was used. Sn-mediated uptake has been reported to enhance humoral immune responses. As C. jejuni strains expressing ganglioside mimics GD1a and GM1a are closely associated with GBS, Sn binding may be a determining event in the production of cross-reactive antibodies and the development of GBS.
Asunto(s)
Campylobacter jejuni/inmunología , Síndrome de Guillain-Barré/microbiología , Macrófagos/microbiología , Lectina 1 Similar a Ig de Unión al Ácido Siálico/metabolismo , Anticuerpos Antibacterianos/biosíntesis , Anticuerpos Antibacterianos/inmunología , Adhesión Bacteriana , Campylobacter jejuni/clasificación , Campylobacter jejuni/metabolismo , Células Cultivadas , Reacciones Cruzadas , Gangliósidos/química , Gangliósidos/inmunología , Síndrome de Guillain-Barré/inmunología , Humanos , Interferón-alfa/inmunología , Interleucina-6/metabolismo , Lipopolisacáridos/química , Lipopolisacáridos/inmunología , Imitación Molecular/inmunología , Fagocitosis , Lectina 1 Similar a Ig de Unión al Ácido Siálico/inmunologíaRESUMEN
Sialoadhesin (Sn) is a macrophage (Mφ)-restricted receptor that recognizes sialylated ligands on host cells and pathogens. Although Sn is thought to be important in cellular interactions of Mφs with cells of the immune system, the functional consequences of pathogen engagement by Sn are unclear. As a model system, we have investigated the role of Sn in Mφ interactions with heat-killed Campylobacter jejuni expressing a GD1a-like, sialylated glycan. Compared to Sn-expressing bone marrow-derived macrophages (BMDM) from wild-type mice, BMDM from mice either deficient in Sn or expressing a non-glycan-binding form of Sn showed greatly reduced phagocytosis of sialylated C. jejuni. This was accompanied by a strong reduction in MyD88-dependent secretion of TNF-α, IL-6, IL-12, and IL-10. In vivo studies demonstrated that functional Sn was required for rapid TNF-α and IFN-ß responses to i.v.-injected sialylated C. jejuni. Bacteria were captured within minutes after i.v. injection and were associated with Mφs in both liver and spleen. In the spleen, IFN-ß-reactive cells were localized to Sn⺠Mφs and other cells in the red pulp and marginal zone. Together, these studies demonstrate that Sn plays a key role in capturing sialylated pathogens and promoting rapid proinflammatory cytokine and type I IFN responses.
Asunto(s)
Campylobacter jejuni/inmunología , Campylobacter jejuni/patogenicidad , Mediadores de Inflamación/metabolismo , Interferón Tipo I/fisiología , Glicoproteínas de Membrana/metabolismo , Receptores Inmunológicos/metabolismo , Sialoglicoproteínas/metabolismo , Animales , Células de la Médula Ósea/inmunología , Células de la Médula Ósea/metabolismo , Células Cultivadas , Femenino , Técnicas de Sustitución del Gen , Interacciones Huésped-Patógeno/inmunología , Mediadores de Inflamación/fisiología , Glicoproteínas de Membrana/fisiología , Ratones , Ratones de la Cepa 129 , Ratones Endogámicos BALB C , Ratones Endogámicos C57BL , Ratones Noqueados , Receptores Inmunológicos/fisiología , Lectina 1 Similar a Ig de Unión al Ácido Siálico , Sialoglicoproteínas/fisiología , Factores de TiempoRESUMEN
Translocation across intestinal epithelial cells is an established pathogenic feature of the zoonotic bacterial species Campylobacter jejuni. The number of C. jejuni virulence factors known to be involved in translocation is limited. In the present study, we investigated whether sialylation of C. jejuni lipooligosaccharide (LOS) structures, generating human nerve ganglioside mimics, is important for intestinal epithelial translocation. We here show that C. jejuni isolates expressing ganglioside-like LOS bound in larger numbers to the Caco-2 intestinal epithelial cells than C. jejuni isolates lacking such structures. Next, we found that ganglioside-like LOS facilitated endocytosis of bacteria into Caco-2 cells, as visualized by quantitative microscopy using the early and late endosomal markers early endosome-associated protein 1 (EEA1), Rab5, and lysosome-associated membrane protein 1 (LAMP-1). This increased endocytosis was associated with larger numbers of surviving and translocating bacteria. Next, we found that two different intestinal epithelial cell lines (Caco-2 and T84) responded with an elevated secretion of the T-cell attractant CXCL10 to infection by ganglioside-like LOS-expressing C. jejuni isolates. We conclude that C. jejuni translocation across Caco-2 cells is facilitated by ganglioside-like LOS, which is of clinical relevance since C. jejuni ganglioside-like LOS-expressing isolates are linked with severe gastroenteritis and bloody stools in C. jejuni-infected patients.
Asunto(s)
Traslocación Bacteriana , Campylobacter jejuni/patogenicidad , Células Epiteliales/microbiología , Gangliósidos/metabolismo , Lipopolisacáridos/metabolismo , Línea Celular , Quimiocina CXCL10/metabolismo , Endocitosis , Humanos , Microscopía FluorescenteRESUMEN
BACKGROUND: Guillain-Barré syndrome (GBS) is a post-infectious polyradiculoneuropathy, frequently associated with antecedent Campylobacter jejuni (C. jejuni) infection. The presence of sialic acid on C. jejuni lipo-oligosaccharide (LOS) is considered a risk factor for development of GBS as it crucially determines the structural homology between LOS and gangliosides, explaining the induction of cross-reactive neurotoxic antibodies. Sialylated C. jejuni are recognised by TLR4 and sialoadhesin; however, the functional implications of these interactions in vivo are unknown. METHODOLOGY/PRINCIPAL FINDINGS: In this study we investigated the effects of bacterial sialylation on phagocytosis and cytokine secretion by mouse myeloid cells in vitro and in vivo. Using fluorescently labelled GM1a/GD1a ganglioside-mimicking C. jejuni strains and corresponding (Cst-II-mutant) control strains lacking sialic acid, we show that sialylated C. jejuni was more efficiently phagocytosed in vitro by BM-MΦ, but not by BM-DC. In addition, LOS sialylation increased the production of IL-10, IL-6 and IFN-ß by both BM-MΦ and BM-DC. Subsequent in vivo experiments revealed that sialylation augmented the deposition of fluorescent bacteria in splenic DC, but not macrophages. In addition, sialylation significantly amplified the production of type I interferons, which was independent of pDC. CONCLUSIONS/SIGNIFICANCE: These results identify novel immune stimulatory effects of C. jejuni sialylation, which may be important in inducing cross-reactive humoral responses that cause GBS.
Asunto(s)
Infecciones por Campylobacter/patología , Campylobacter jejuni/metabolismo , Citocinas/metabolismo , Lipopolisacáridos/metabolismo , Ácido N-Acetilneuramínico/metabolismo , Fagocitosis , Animales , Células Dendríticas/inmunología , Células Dendríticas/metabolismo , Gangliósidos/metabolismo , Síndrome de Guillain-Barré/fisiopatología , Interferón beta/metabolismo , Interleucina-10/metabolismo , Interleucina-6/metabolismo , Macrófagos/inmunología , Macrófagos/metabolismo , Ratones , Ratones Endogámicos C57BL , Células Mieloides/metabolismo , Bazo/inmunologíaRESUMEN
Monolithic columns containing ganglioside GM2 and GM3 mimics were prepared for selective removal of serum anti-ganglioside antibodies from patients with acute and chronic immune-mediated neuropathies. ELISA results demonstrated that anti-GM2 IgM antibodies in human sera and a mouse monoclonal anti-GM2 antibody were specifically and selectively adsorbed by monolithic GM2 mimic columns and not by blank monolithic columns or monolithic GM3 mimic columns. In control studies, serum antibodies against the ganglioside GQ1b from another neuropathy patient were not depleted by monolithic GM2 mimic columns. Fluorescence microscopy with FITC-conjugated anti-human immunoglobulin antibodies showed that the immobilized ganglioside mimics were evenly distributed along the column. The columns were able to capture â¼95% of the anti-GM2 antibodies of patients after only 2 min of incubation. A monolithic column of 4.4 µL can deplete 28.2 µL of undiluted serum. These columns are potential diagnostic and therapeutic tools for neuropathies related to anti-ganglioside antibodies.
Asunto(s)
Química Farmacéutica/métodos , Diseño de Fármacos , Gangliósidos/química , Adsorción , Animales , Anticuerpos Monoclonales/química , Ensayo de Inmunoadsorción Enzimática/métodos , Fluoresceína-5-Isotiocianato/farmacología , Gangliósido G(M2)/química , Humanos , Inmunoglobulina M/química , Ratones , Microscopía Fluorescente/métodos , Sistema Nervioso Periférico/patología , Enfermedades del Sistema Nervioso Periférico/tratamiento farmacológicoRESUMEN
Carbohydrate mimicry between Campylobacter jejuni lipooligosaccharides (LOS) and host neural gangliosides plays a crucial role in the pathogenesis of Guillain-Barré syndrome (GBS). Campylobacter jejuni LOS may mimic various gangliosides, which affects the immunogenicity and the type of neurological deficits in GBS patients. Previous studies have shown the interaction of LOS with sialic acid-specific siglec receptors, although the functional consequences remain unknown. Cells that express high levels of siglecs include dendritic cells (DCs), which are crucial for initiation and differentiation of immune responses. We confirm that α2,3-sialylated GD1a/GM1a mimic and α2,8-sialylated GD1c mimic LOS structures interact with recombinant Sn and siglec-7, respectively. Although the linkage of the terminal sialic acid of LOS did not regulate expression of DC maturation markers, it displayed clear opposite expression levels of interleukin-12 (IL-12) and OX40L, molecules involved in DC-mediated Th cell differentiation. Accordingly, targeting DC-expressed siglec-7 with α2,8-linked sialylated LOS resulted in Th1 responses, whereas Th2 responses were induced by targeting with LOS containing α2,3-linked sialic acid. Thus, our data demonstrate for the first time that depending on the sialylated composition of Campylobacter jejuni LOS, specific Th differentiation programs are initiated, possibly through targeting of distinct DC-expressed siglecs.
Asunto(s)
Campylobacter jejuni/inmunología , Células Dendríticas/inmunología , Lipopolisacáridos/inmunología , Lipopolisacáridos/metabolismo , Linfocitos T/inmunología , Campylobacter jejuni/química , Campylobacter jejuni/metabolismo , Conformación de Carbohidratos , Diferenciación Celular , Línea Celular , Polaridad Celular , Células Dendríticas/metabolismo , Ensayo de Inmunoadsorción Enzimática , Citometría de Flujo , Gangliósido G(M1)/química , Gangliósidos/química , Gangliósidos/inmunología , Gangliósidos/metabolismo , Síndrome de Guillain-Barré/inmunología , Síndrome de Guillain-Barré/microbiología , Células HEK293 , Humanos , Interleucina-12/biosíntesis , Interleucina-12/genética , Interleucina-12/inmunología , Lectinas/metabolismo , Lipopolisacáridos/química , Imitación Molecular , Ácido N-Acetilneuramínico/química , Ácido N-Acetilneuramínico/inmunología , Ácido N-Acetilneuramínico/metabolismo , Ligando OX40/biosíntesis , Ligando OX40/genética , Reacción en Cadena de la Polimerasa , Lectinas Similares a la Inmunoglobulina de Unión a Ácido Siálico , Linfocitos T/metabolismo , Células TH1/inmunología , Células Th2/inmunologíaRESUMEN
In Guillain-Barré syndrome (GBS), ganglioside mimicry of Campylobacter jejuni lipo-oligosaccharide (LOS) drives the production of cross-reactive Abs to peripheral nerve gangliosides. We determined whether sialic acid residues in C. jejuni LOS modulate dendritic cell (DC) activation and subsequent B cell proliferation as a possible mechanism for the aberrant humoral immune response in GBS. Highly purified sialylated LOS of C. jejuni isolates from three GBS patients induced human DC maturation and secretion of inflammatory cytokines that were inhibited by anti-TLR4 neutralizing Abs. The extent of TLR4 signaling and DC activation was greater with LOS of the wild type isolates than with nonsialylated LOS of the corresponding sialyltransferase gene knockout (cst-II mutant) strains, indicating that sialylation boosts the DC response to C. jejuni LOS. Supernatants of LOS-activated DCs induced B cell proliferation after cross-linking of surface Igs in the absence of T cells. Lower B cell proliferation indices were found with DC supernatants after DC stimulation with cst-II mutant or neuraminidase desialylated LOS. This study showed that sialylation of C. jejuni LOS enhances human DC activation and subsequent B cell proliferation, which may contribute to the development of cross-reactive anti-ganglioside Abs found in GBS patients following C. jejuni infection.
Asunto(s)
Antígenos Bacterianos/metabolismo , Campylobacter jejuni/inmunología , Células Dendríticas/inmunología , Células Dendríticas/metabolismo , Síndrome de Guillain-Barré/inmunología , Síndrome de Guillain-Barré/metabolismo , Lipopolisacáridos/metabolismo , Receptor Toll-Like 4/fisiología , Animales , Anticuerpos Antibacterianos/biosíntesis , Antígenos Bacterianos/inmunología , Subgrupos de Linfocitos B/citología , Subgrupos de Linfocitos B/inmunología , Subgrupos de Linfocitos B/microbiología , Campylobacter jejuni/química , Secuencia de Carbohidratos , Diferenciación Celular/genética , Diferenciación Celular/inmunología , Línea Celular , Proliferación Celular , Sistema Libre de Células/inmunología , Células Cultivadas , Reacciones Cruzadas , Citocinas/metabolismo , Células Dendríticas/microbiología , Técnicas de Sustitución del Gen , Síndrome de Guillain-Barré/microbiología , Humanos , Mucosa Intestinal/citología , Mucosa Intestinal/inmunología , Mucosa Intestinal/microbiología , Lipopolisacáridos/química , Lipopolisacáridos/inmunología , Ratones , Ratones Endogámicos C3H , Datos de Secuencia Molecular , Ácidos Siálicos/química , Ácidos Siálicos/inmunología , Ácidos Siálicos/metabolismo , Sialiltransferasas/deficiencia , Sialiltransferasas/genética , Transducción de Señal/inmunologíaRESUMEN
In Campylobacter jejuni-induced Guillain-Barré syndrome (GBS), molecular mimicry between C. jejuni lipooligosaccharide (LOS) and host gangliosides leads to the production of cross-reactive antibodies directed against the peripheral nerves of the host. Currently, the presence of surface exposed sialylated LOS in C. jejuni is the single known bacterial pathogenesis factor associated with the development of GBS. Using a unique, well-characterized strain collection, we demonstrate that GBS-associated C. jejuni strains bind preferentially to sialoadhesin (Sn, Siglec-1, or CD169), a sialic acid receptor found on a subset of macrophages. In addition, using a whole-cell enzyme-linked immunosorbent assay (ELISA), C. jejuni strains with sialylated LOS bound exclusively to soluble Sn. Mass spectrometry revealed that binding was sialic acid-linkage specific with a preference for alpha(2,3)-linked sialic acid attached to the terminal galactose of the LOS chain as seen in the gangliosides GD1a, GM1b, and GM3. This molecular interaction was also related to functional consequences as a GBS-associated C. jejuni strain that bound Sn in a whole-cell ELISA adhered to surface-expressed Sn of Sn-transfected CHO cells but was unable to adhere to wild-type CHO cells. Moreover, a sialic acid-negative mutant of the same C. jejuni strain was unable to bind Sn-transfected CHO cells. This is the first report of the preferential binding of GBS-associated C. jejuni strains to the Sn immune receptor (P = 0.014). Moreover, because this binding is dependent on sialylated LOS, the main pathogenic factor in GBS progression, the present findings bring us closer to unraveling the mechanisms that lead to formation of cross-reactive antibodies in GBS disease.
Asunto(s)
Infecciones por Campylobacter/microbiología , Campylobacter jejuni/fisiología , Lipopolisacáridos/fisiología , Glicoproteínas de Membrana/fisiología , Receptores Inmunológicos/fisiología , Animales , Células CHO/microbiología , Cricetinae , Cricetulus , Ensayo de Inmunoadsorción Enzimática , Gangliósidos/metabolismo , Síndrome de Guillain-Barré/microbiología , Humanos , Ácido N-Acetilneuramínico/metabolismo , Lectina 1 Similar a Ig de Unión al Ácido SiálicoRESUMEN
Campylobacter jejuni lipooligosaccharide (LOS) can trigger Guillain-Barré syndrome (GBS) due to its similarity to human gangliosides. Rapid and accurate structural elucidation of the LOS glycan of a strain isolated from a GBS patient could help physicians determine the spectrum of anti-ganglioside antibodies likely to be found and therefore provide valuable assistance in establishing an appropriate course of treatment. The ability of implemented mass spectrometry-based approaches in a clinical setting has been limited by the laborious and time-consuming nature of the protocols, typically 3 to 4 days, used to prepare LOS. In order to improve the analytical throughput, microwave-assisted enzymatic digestion was investigated. In this study, the bacterial cells were suspended in 50 microl of 20 mM ammonium acetate buffer containing DNase and RNase and treated by direct microwave irradiation for 3 min. Then, proteinase K was added and the samples were again microwaved. The intact LOS samples were analyzed using electrophoresis-assisted open-tubular liquid chromatography-mass spectrometry. The reliability of the rapid, high-throughput technique was demonstrated through analysis of LOS glycans from 73 C. jejuni strains. The structure was elucidated using material from a single colony. The total time for sample preparation and MS analysis is less than 60 min.