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Inflammatory bowel disease (IBD) is characterized by chronic inflammation in the gut. There is growing evidence in Crohn's disease (CD) of the existence of a preclinical period characterized by immunological changes preceding symptom onset that starts years before diagnosis. Gaining insight into this preclinical phase will allow disease prediction and prevention. Analysis of preclinical serum samples, up to 6 years before IBD diagnosis (from the PREDICTS cohort), revealed the identification of a unique glycosylation signature on circulating antibodies (IgGs) characterized by lower galactosylation levels of the IgG fragment crystallizable (Fc) domain that remained stable until disease diagnosis. This specific IgG2 Fc glycan trait correlated with increased levels of antimicrobial antibodies, specifically anti-Saccharomyces cerevisiae (ASCA), pinpointing a glycome-ASCA hub detected in serum that predates by years the development of CD. Mechanistically, we demonstrated that this agalactosylated glycoform of ASCA IgG, detected in the preclinical phase, elicits a proinflammatory immune pathway through the activation and reprogramming of innate immune cells, such as dendritic cells and natural killer cells, via an FcγR-dependent mechanism, triggering NF-κB and CARD9 signaling and leading to inflammasome activation. This proinflammatory role of ASCA was demonstrated to be dependent on mannose glycan recognition and galactosylation levels in the IgG Fc domain. The pathogenic properties of (anti-mannose) ASCA IgG were validated in vivo. Adoptive transfer of antibodies to mannan (ASCA) to recipient wild-type mice resulted in increased susceptibility to intestinal inflammation that was recovered in recipient FcγR-deficient mice. Here we identify a glycosylation signature in circulating IgGs that precedes CD onset and pinpoint a specific glycome-ASCA pathway as a central player in the initiation of inflammation many years before CD diagnosis. This pathogenic glyco-hub may constitute a promising new serum biomarker for CD prediction and a potential target for disease prevention.
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Enfermedad de Crohn , Inmunoglobulina G , Manosa , Polisacáridos , Enfermedad de Crohn/inmunología , Enfermedad de Crohn/sangre , Inmunoglobulina G/inmunología , Inmunoglobulina G/sangre , Animales , Humanos , Glicosilación , Manosa/metabolismo , Manosa/inmunología , Ratones , Polisacáridos/inmunología , Polisacáridos/metabolismo , Femenino , Saccharomyces cerevisiae/inmunología , Masculino , Adulto , Anticuerpos Antifúngicos/sangre , Anticuerpos Antifúngicos/inmunología , Ratones Endogámicos C57BL , Ratones Noqueados , Biomarcadores/sangre , Persona de Mediana Edad , Fragmentos Fc de Inmunoglobulinas/inmunología , GlicoproteínasRESUMEN
Enterotoxigenic Escherichia coli (ETEC) cause hundreds of millions of cases of infectious diarrhea annually, predominantly in children from low-middle income regions. Notably, in children, as well as human volunteers challenged with ETEC, diarrheal severity is significantly increased severity in blood group A (bgA) individuals. EtpA, is a secreted glycoprotein adhesin that functions as a blood group A lectin to promote critical interactions between ETEC and blood group A glycans on intestinal epithelia for effective bacterial adhesion and toxin delivery. EtpA is highly immunogenic resulting in robust antibody responses following natural infection and experimental challenge of human volunteers with ETEC. To understand how EtpA directs ETEC-blood group A interactions and stimulates adaptive immunity, we mutated EtpA, mapped its glycosylation by mass-spectrometry (MS), isolated polyclonal (pAbs) and monoclonal antibodies (mAbs) from vaccinated mice and ETEC-infected human volunteers, and determined structures of antibody-EtpA complexes by cryo-electron microscopy. Both bgA and mAbs that inhibited EtpA-bgA interactions and ETEC adhesion, bound to the C-terminal repeat domain highlighting this region as crucial for ETEC pathogen-host interaction. MS analysis uncovered extensive and heterogeneous N-linked glycosylation of EtpA and cryo-EM structures revealed that mAbs directly engage these unique glycan containing epitopes. Finally, electron microscopy-based polyclonal epitope mapping revealed antibodies targeting numerous distinct epitopes on N and C-terminal domains, suggesting that EtpA vaccination generates responses against neutralizing and decoy regions of the molecule. Collectively, we anticipate that these data will inform our general understanding of pathogen-host glycan interactions and adaptive immunity relevant to rational vaccine subunit design.
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BACKGROUND: Enterotoxigenic E. coli (ETEC) is a principal cause of diarrhea in travelers, deployed military personnel, and children living in low to middle-income countries. ETEC expresses a variety of virulence factors including colonization factors (CF) that facilitate adherence to the intestinal mucosa. We assessed the protective efficacy of a tip-localized subunit of CF antigen I (CFA/I), CfaE, delivered intradermally with the mutant E. coli heat-labile enterotoxin, LTR192G, in a controlled human infection model (CHIM). METHODS: Three cohorts of healthy adult subjects were enrolled and given three doses of 25 µg CfaE + 100 ng LTR192G vaccine intradermally at 3-week intervals. Approximately 28 days after the last vaccination, vaccinated and unvaccinated subjects were admitted as inpatients and challenged with approximately 2 × 107 cfu of CFA/I+ ETEC strain H10407 following an overnight fast. Subjects were assessed for moderate-to-severe diarrhea for 5 days post-challenge. RESULTS: A total of 52 volunteers received all three vaccinations; 41 vaccinated and 43 unvaccinated subjects were challenged and assessed for moderate-to-severe diarrhea. Naïve attack rates varied from 45.5% to 64.7% across the cohorts yielding an overall efficacy estimate of 27.8% (95% confidence intervals: -7.5-51.6%). In addition to reducing moderate-severe diarrhea rates, the vaccine significantly reduced loose stool output and overall ETEC disease severity. CONCLUSIONS: This is the first study to demonstrate protection against ETEC challenge after intradermal vaccination with an ETEC adhesin. Further examination of the challenge methodology is necessary to address the variability in naïve attack rate observed among the three cohorts in the present study.
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Infectious diarrhea is a World Health Organization public health priority area due to the lack of effective vaccines and an accelerating global antimicrobial resistance crisis. New strategies are urgently needed such as immunoprophylactic for prevention of diarrheal diseases. Hyperimmune bovine colostrum (HBC) is an established and effective prophylactic for infectious diarrhea. The commercial HBC product, Travelan® (Immuron Ltd, Australia) targets multiple strains of enterotoxigenic Escherichia coli (ETEC) is highly effective in preventing diarrhea in human clinical studies. Although Travelan® targets ETEC, preliminary studies suggested cross-reactivity with other Gram-negative enteric pathogens including Shigella and Salmonella species. For this study we selected an invasive diarrheal/dysentery-causing enteric pathogen, Shigella, to evaluate the effectiveness of Travelan®, both in vitro and in vivo. Here we demonstrate broad cross-reactivity of Travelan® with all four Shigella spp. (S. flexneri, S. sonnei, S. dysenteriae and S. boydii) and important virulence factor Shigella antigens. Naïve juvenile rhesus macaques (NJRM) were randomized, 8 dosed with Travelan® and 4 with a placebo intragastrically twice daily over 6 days. All NJRM were challenged with S. flexneri 2a strain 2457T on the 4th day of treatment and monitored for diarrheal symptoms. All placebo-treated NJRM displayed acute dysentery symptoms within 24-36 hours of challenge. Two Travelan®-treated NJRM displayed dysentery symptoms and six animals remained healthy and symptom-free post challenge; resulting in 75% efficacy of prevention of shigellosis (p = 0.014). These results strongly indicate that Travelan® is functionally cross-reactive and an effective prophylactic for shigellosis. This has positive implications for the prophylactic use of Travelan® for protection against both ETEC and Shigella spp. diarrheal infections. Future refinement and expansion of pathogens recognized by HBC including Travelan® could revolutionize current management of gastrointestinal infections and outbreaks in travelers' including military, peacekeepers, humanitarian workers and in populations living in endemic regions of the world.
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Disentería Bacilar , Disentería , Escherichia coli Enterotoxigénica , Shigella , Femenino , Embarazo , Animales , Bovinos , Humanos , Disentería Bacilar/epidemiología , Macaca mulatta , Calostro , Factores Inmunológicos , Diarrea/prevención & controlRESUMEN
INTRODUCTION: Enterotoxigenic E. coli (ETEC) is a leading cause of diarrhea in travelers as well as for children living in low- to middle-income countries. ETEC adhere to intestinal epithelium via colonization factors (CFs). CFA/I, a common CF, is composed of a polymeric stalk and a tip-localized minor adhesive subunit, CfaE. Vaccine delivery by the transcutaneous immunization of dscCfaE was safe but was poorly immunogenic in a phase 1 trial when administered to volunteers with LTR(192G) and mLT. To potentially enhance the immunogenicity of CfaE while still delivering via a cutaneous route, we evaluated the safety and immunogenicity of two CfaE constructs administered intradermally (ID) with or without mLT. METHODS: CfaE was evaluated as a donor strand-complemented construct (dscCfaE) and as a chimeric construct (Chimera) in which dscCfaE replaces the A1 domain of the cholera toxin A subunit and assembles non-covalently with the pentamer of heat-labile toxin B (LTB). Subjects received three ID vaccinations three weeks apart with either dscCfaE (1, 5, and 25 µg) or Chimera (2.6 and 12.9 µg) with and without 0.1 µg of mLT. Subjects were monitored for local and systemic adverse events. Immunogenicity was evaluated by serum and antibody-secreting cell (ASC) responses. RESULTS: The vaccine was well-tolerated with predominantly mild and moderate local vaccine site reactions characterized by erythema, induration and post-inflammatory hyperpigmentation. High rates of serologic and ASC responses were seen across study groups with the most robust responses observed in subjects receiving 25 µg of dscCfaE with 0.1 mcg of LT(R192G). CONCLUSION: Both ETEC adhesin vaccine prototypes were safe and immunogenic when co-administered with mLT by the ID route. The observed immune responses induced with the high dose of dscCfaE and mLT warrant further assessment in a controlled human infection model.
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A key aspect to vaccine efficacy is formulation stability. Biochemical evaluations provide information on optimal compositions or thermal stability but are routinely validated by ex vivo analysis and not efficacy in animal models. Here we assessed formulations identified to improve or reduce stability of the mucosal adjuvant dmLT being investigated in polio and enterotoxigenic E. coli (ETEC) clinical vaccines. We observed biochemical changes to dmLT protein with formulation or thermal stress, including aggregation or subunit dissociation or alternatively resistance against these changes with specific buffer compositions. However, upon injection or mucosal vaccination with ETEC fimbriae adhesin proteins or inactivated polio virus, experimental findings indicated immunization route and co-administered antigen impacted vaccine immunogenicity more so than dmLT formulation stability (or instability). These results indicate the importance of both biochemical and vaccine-derived immunity assessment in formulation optimization. In addition, these studies have implications for use of dmLT in clinical settings and for delivery in resource poor settings.
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Escherichia coli Enterotoxigénica , Infecciones por Escherichia coli , Proteínas de Escherichia coli , Vacunas contra Escherichia coli , Poliomielitis , Animales , Enterotoxinas , Excipientes , Escherichia coli , Infecciones por Escherichia coli/prevención & control , Adyuvantes Inmunológicos , AntígenosRESUMEN
BACKGROUND & AIMS: Better biomarkers for prediction of ulcerative colitis (UC) development and prognostication are needed. Anti-integrin αvß6 (anti-αvß6) autoantibodies have been described in patients with UC. We tested for the presence of anti-αvß6 antibodies in the preclinical phase of UC and studied their association with disease-related outcomes after diagnosis. METHODS: Anti-αvß6 autoantibodies were measured in 4 longitudinal serum samples collected from 82 subjects who later developed UC and 82 matched controls from a Department of Defense preclinical cohort (PREDICTS [Proteomic Evaluation and Discovery in an IBD Cohort of Tri-service Subjects]). In a distinct, external validation cohort (Crohn's and Colitis Canada Genetic Environmental Microbial project cohort), we tested 12 pre-UC subjects and 49 matched controls. Furthermore, anti-αvß6 autoantibodies were measured in 2 incident UC cohorts (COMPASS [Comprehensive Care for the Recently Diagnosed IBD Patients], n = 55 and OSCCAR [Ocean State Crohn's and Colitis Area Registry], n = 104) and associations between anti-αvß6 autoantibodies and UC-related outcomes were defined using Cox proportional hazards model. RESULTS: Anti-αvß6 autoantibodies were significantly higher among individuals who developed UC compared with controls up to 10 years before diagnosis in PREDICTS. The anti-αvß6 autoantibody seropositivity was 12.2% 10 years before diagnosis and increased to 52.4% at the time of diagnosis in subjects who developed UC compared with 2.7% in controls across the 4 time points. Anti-αvß6 autoantibodies predicted UC development with an area under the curve of at least 0.8 up to 10 years before diagnosis. The presence of anti-αvß6 autoantibodies in preclinical UC samples was validated in the GEM cohort. Finally, high anti-αvß6 autoantibodies was associated with a composite of adverse UC outcomes, including hospitalization, disease extension, colectomy, systemic steroid use, and/or escalation to biologic therapy in recently diagnosed UC. CONCLUSIONS: Anti-integrin αvß6 autoantibodies precede the clinical diagnosis of UC by up to 10 years and are associated with adverse UC-related outcomes.
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Colitis Ulcerosa , Colitis , Enfermedad de Crohn , Humanos , Colitis Ulcerosa/tratamiento farmacológico , Autoanticuerpos , Proteómica , Enfermedad de Crohn/tratamiento farmacológico , Biomarcadores , Colitis/complicacionesRESUMEN
OBJECTIVE: To identify a panel of serum biomarkers that could specifically identify imminent cases of rheumatoid arthritis (RA) before diagnosis. METHODS: Serum samples were collected at 4 time points from active component US military personnel, including 157 anti-citrullinated protein antibody (ACPA)-seropositive and 50 ACPA-seronegative RA subjects, 100 reactive arthritis (ReA) subjects, and 76 healthy controls. The cohorts were split into 2 phases, with samples tested on independent proteomic platforms for each phase. Classification models of RA diagnosis based on samples obtained within 6 months prior to diagnosis were developed both in univariate analyses and by multivariate random forest modeling of training sample sets and testing sample sets from each phase. RESULTS: Increases in serum analytes, including C-reactive protein levels, serum amyloid A, and soluble programmed cell death 1 (PD-1), were observed in seropositive RA subjects at the time point closest to diagnosis, up to several years before diagnosis. Only a small fraction of RA subjects had levels above the 95th percentile of healthy control levels until the time period within 6 months of diagnosis. For classification of RA diagnosis using samples obtained within 6 months prior to diagnosis, soluble PD-1 provided superior specificity compared to ReA cases (>89%), with a sensitivity of 48% for RA classification. An 8-analyte model provided superior sensitivity (69%), with comparable specificity relative to ReA (>82%). CONCLUSION: Our findings demonstrate that imminent RA diagnosis could be classified with high specificity, relative to healthy controls and ReA cases, using a panel of cytokines measured in serum samples collected within 6 months before actual diagnosis.
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Artritis Reactiva , Artritis Reumatoide , Personal Militar , Humanos , Proteómica , Receptor de Muerte Celular Programada 1 , BiomarcadoresRESUMEN
BACKGROUND & AIMS: Anti-granulocyte macrophage-colony stimulating factor autoantibodies (aGMAbs) are detected in patients with ileal Crohn's disease (CD). Their induction and mode of action during or before disease are not well understood. We aimed to investigate the underlying mechanisms associated with aGMAb induction, from functional orientation to recognized epitopes, for their impact on intestinal immune homeostasis and use as a predictive biomarker for complicated CD. METHODS: We characterized using enzyme-linked immunosorbent assay naturally occurring aGMAbs in longitudinal serum samples from patients archived before the diagnosis of CD (n = 220) as well as from 400 healthy individuals (matched controls) as part of the US Defense Medical Surveillance System. We used biochemical, cellular, and transcriptional analysis to uncover a mechanism that governs the impaired immune balance in CD mucosa after diagnosis. RESULTS: Neutralizing aGMAbs were found to be specific for post-translational glycosylation on granulocyte macrophage-colony stimulating factor (GM-CSF), detectable years before diagnosis, and associated with complicated CD at presentation. Glycosylation of GM-CSF was altered in patients with CD, and aGMAb affected myeloid homeostasis and promoted group 1 innate lymphoid cells. Perturbations in immune homeostasis preceded the diagnosis in the serum of patients with CD presenting with aGMAb and were detectable in the noninflamed CD mucosa. CONCLUSIONS: Anti-GMAbs predict the diagnosis of complicated CD long before the diagnosis of disease, recognize uniquely glycosylated epitopes, and impair myeloid cell and innate lymphoid cell balance associated with altered intestinal immune homeostasis.
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Enfermedad de Crohn , Enfermedades del Íleon , Autoanticuerpos , Enfermedad de Crohn/complicaciones , Epítopos , Glicosilación , Factor Estimulante de Colonias de Granulocitos y Macrófagos/metabolismo , Humanos , Enfermedades del Íleon/complicaciones , Inmunidad Innata , Linfocitos , MacrófagosRESUMEN
Campylobacter jejuni infection is a leading cause of foodborne disease, common to children, adult travelers, and military populations in low- to middle-income countries. In the absence of a licensed vaccine, efforts to evaluate prophylactic agents are underway. The prophylactic efficacy of a twice-daily, 550 mg dose of the antibiotic rifaximin demonstrated no efficacy against campylobacteriosis in a controlled human infection model (CHIM); however, samples from the CHIM study were utilized to assess how the human gut microbiome responds to C. jejuni infection, and if a 'protective' microbiota exists in study participants not developing campylobacteriosis. Statistically significant, but minor, differences in study participant beta diversity were identified during the challenge period (p = 0.002, R2 = 0.042), but no significant differences were otherwise observed. Pre-challenge alpha diversity was elevated in study participants who did not develop campylobacteriosis compared to those who did (p < 0.001), but alpha diversity declined in all study participants from the pre-challenge period to post-discharge. Our work provides insight into gut microbiome shifts observed during a C. jejuni CHIM and following antibiotic treatment. This study utilized a high dose of 1.7 x 105 colony-forming units of C. jejuni; future work could include CHIM studies performed with inocula more closely mimicking natural exposure as well as field studies involving naturally-occurring enteric infections.
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Infecciones por Campylobacter , Campylobacter jejuni , Microbioma Gastrointestinal , Adulto , Cuidados Posteriores , Niño , Humanos , Alta del PacienteRESUMEN
Enterotoxigenic Escherichia coli (ETEC) is a leading cause of diarrhea among travelers and pediatric populations worldwide. The tip-localized adhesin of colonization factor antigen (CFA)/I fimbriae was engineered as a donor strand complemented variant (dscCfaE) and delivered via transcutaneous immunization. Preclinical vaccine testing demonstrated safety, immunogenicity and efficacy. A series of open-label dose-escalating phase 1 studies evaluated a 3-dose (days 0, 21, 42) regimen via a transcutaneous skin patch. A total of forty-six subjects were enrolled into one of four vaccine dose levels (10, 50, 250, or 1250 µg) co-administered with single-mutant heat-labile enterotoxin (LTR(192G)). At the 50 µg dose level, ten subjects received the dscCfaE vaccine without LT(R192G). The vaccine was well tolerated with mild local vaccine site reactions characterized by an erythematous papular rash and pruritus, which were less frequent and reactive in the group not receiving LT(R192G). The frequency of responses to dscCfaE were moderate, whereas anti-toxin responses (serum IgA/IgG) ranged from 75 to 100% across groups that received LT(R192G). Antigen-specific antibody-secreting cell responses were elicited at all dose levels, but were generally low. Follow-on studies will optimize construct and route of delivery and assess efficacy in an ETEC challenge study.
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Toxinas Bacterianas , Escherichia coli Enterotoxigénica , Infecciones por Escherichia coli , Proteínas de Escherichia coli , Vacunas contra Escherichia coli , Anticuerpos Antibacterianos , Toxinas Bacterianas/genética , Niño , Enterotoxinas/genética , Infecciones por Escherichia coli/prevención & control , Proteínas de Escherichia coli/genética , Calor , Humanos , Inmunoglobulina A , MutaciónRESUMEN
BACKGROUND & AIMS: Biomarkers are needed to identify patients at risk for development of inflammatory bowel diseases. We aimed to identify serum biomarkers of Crohn's disease and ulcerative colitis that can be detected and quantified before diagnosis. METHODS: We obtained serum samples from patients archived before a diagnosis of Crohn's disease (n = 200) or ulcerative colitis (n = 199), as well as from 200 healthy individuals (controls), collected from 1998 through 2013 as part of the US Defense Medical Surveillance System. We measured levels of antibodies against microbes (anti-Saccharomyces cerevisiae IgA or IgG, anti-Escherichiacoli outer membrane porin C, anti-CBir1, anti-flagellin 2, anti-flagellin X, and perinuclear anti-neutrophil cytoplasmic antibodies) and 1129 proteins in each sample. We then used functional principal component analysis to derive the time-varying trajectory for each marker, which then was used in a multivariate model to predict disease status. Predictive performances at different prediagnosis timepoints were evaluated using area under the receiver operating characteristic curves (AUROCs). Biological pathways that were up-regulated in serum from patients with Crohn's disease were identified based on changes in protein abundance at different time periods preceding diagnosis. RESULTS: We identified a panel of 51 protein biomarkers that were predictive of Crohn's disease within 5 years with an AUROC of 0.76 and a diagnosis within 1 year with an AUROC of 0.87. Based on the proteins included in the panel, imminent development of CD was associated with changes in the complement cascade, lysosomes, innate immune response, and glycosaminoglycan metabolism. Serum antibodies and proteins identified patients who received a diagnosis of ulcerative colitis within 5 years with an AUROC of only 0.56 and within 1 year with an AUROC of 0.72. CONCLUSIONS: We identified a panel of serum antibodies and proteins that were predictive of patients who will receive a diagnosis of Crohn's disease within 5 years with high accuracy. By contrast we did not identify biomarkers associated with future diagnosis of ulcerative colitis.
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Anticuerpos Anticitoplasma de Neutrófilos/sangre , Anticuerpos Antibacterianos/sangre , Anticuerpos Antifúngicos/sangre , Colitis Ulcerosa/diagnóstico , Enfermedad de Crohn/diagnóstico , Adulto , Anticuerpos Anticitoplasma de Neutrófilos/inmunología , Anticuerpos Antibacterianos/inmunología , Anticuerpos Antifúngicos/inmunología , Biomarcadores/sangre , Estudios de Casos y Controles , Colitis Ulcerosa/sangre , Colitis Ulcerosa/inmunología , Enfermedad de Crohn/sangre , Enfermedad de Crohn/inmunología , Escherichia coli/inmunología , Femenino , Voluntarios Sanos , Humanos , Inmunidad Innata , Masculino , Modelos Estadísticos , Valor Predictivo de las Pruebas , Pronóstico , Proteómica , Curva ROC , Saccharomyces cerevisiae/inmunología , Factores de Tiempo , Adulto JovenRESUMEN
PURPOSE: The etiology of several autoimmune disorders, including rheumatoid arthritis, remains unknown. While there are clear phases of disease progression, the mechanisms of transition between these phases are poorly understood. Additionally, treatment focuses on an alteration of the biological processes to prevent joint damage and functional decline. A goal is to potentially treat the disease during the preclinical phase to mitigate the disease process. Reactive arthritis is another rheumatologic condition known to be secondary to a distal infection. While prevention of infection would mitigate risk, serologic profiling patients with the disease may assist in the elucidation of potential disease risk factors. This study was initiated to enable an assessment of pre-disease biomarkers in patients newly diagnosed with rheumatoid arthritis and reactive arthritis. PARTICIPANTS: A retrospective cohort of 500 rheumatoid and 500 reactive arthritis cases with 500 matched controls was drawn from a population of active component US military personnel. Appropriate inclusion criteria limited subject selection. Additionally, 4 serum samples (3 pre-disease and 1 disease-associated) were obtained for each case and control. FINDINGS TO DATE: The established cohort provides the framework for novel exploration of the host response through serum profiling and seroepidemiology prior to disease onset. FUTURE PLANS: This study establishes the framework for the evaluation of novel serum biomarkers enabling the identification of signals prior to clinical disease that may enable disease prediction, elucidate disease pathogenesis and identify novel exposures leading to increased disease risk and/or disease severity.
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The development of an effective subunit vaccine is frequently complicated by the difficulty of eliciting protective immune responses, often requiring the co-administration of an adjuvant. Heat-labile toxin (LT), an enterotoxin expressed by enterotoxigenic E. coli (ETEC) with an AB5 structure similar to cholera toxin, is a strong adjuvant. While the mucosa represents the natural route of exposure to LT and related toxins, the clinical utility of LT and similar adjuvants given by mucosal routes has been limited by toxicity, as well as the association between intranasal delivery of LT and Bell's palsy. Single and double amino acid mutants of LT, LT(R192G)/mLT and LT(R192G/L211A)/dmLT respectively, have been proposed as alternatives to reduce the toxicity associated with the holotoxin. In the present study, we compared mLT and dmLT given via a non-mucosal route (i.e. intradermally) to investigate their adjuvanticity when co-administrated with an enterotoxigenic E. coli vaccine candidate, CfaEB. Antigenicity (i.e. ability to elicit response against LT) and reactogenicity at the injection site were also evaluated. BALB/c mice were immunized by the intradermal route with CfaEB plus increasing doses of either mLT or dmLT (0.01 to 2.5 µg). Both adjuvants induced dose-dependent skin reactogenicity, with dmLT being less reactogenic than mLT. Both adjuvants significantly boosted the anti-CfaE IgG and functional hemagglutination inhibiting (HAI) antibody responses, compared to the antigen alone. In addition to inducing anti-LT responses, even at the lowest dose tested (0.01 µg), the adjuvants also prompted in vitro cytokine responses (IFN-γ, IL-4, IL-5, IL-10 and IL-17) that followed different patterns, depending on the protein used for stimulation (CfaE or LTB) and/or the dose used for immunization. The two LT mutants evaluated here, mLT and dmLT, are potent adjuvants for intradermal immunization and should be further investigated for the intradermal delivery of subunit ETEC vaccines.
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Antígenos Bacterianos/inmunología , Toxinas Bacterianas/inmunología , Escherichia coli Enterotoxigénica/inmunología , Enterotoxinas/inmunología , Proteínas de Escherichia coli/inmunología , Adyuvantes Inmunológicos/administración & dosificación , Administración a través de la Mucosa , Animales , Anticuerpos Antibacterianos/inmunología , Toxina del Cólera/inmunología , Femenino , Inmunización/métodos , Inyecciones Intradérmicas/métodos , Ratones , Ratones Endogámicos BALB C , Vacunación/métodos , Vacunas de Subunidad/inmunologíaRESUMEN
Campylobacter jejuni is among the most common causes of diarrheal disease worldwide and efforts to develop protective measures against the pathogen are ongoing. One of the few defined virulence factors targeted for vaccine development is the capsule polysaccharide (CPS). We have developed a capsule conjugate vaccine against C. jejuni strain 81-176 (CPS-CRM) that is immunogenic in mice and nonhuman primates (NHPs) but only moderately immunogenic in humans when delivered alone or with aluminum hydroxide. To enhance immunogenicity, two novel liposome-based adjuvant systems, the Army Liposome Formulation (ALF), containing synthetic monophosphoryl lipid A, and ALF plus QS-21 (ALFQ), were evaluated with CPS-CRM in this study. In mice, ALF and ALFQ induced similar amounts of CPS-specific IgG that was significantly higher than levels induced by CPS-CRM alone. Qualitative differences in antibody responses were observed where CPS-CRM alone induced Th2-biased IgG1, whereas ALF and ALFQ enhanced Th1-mediated anti-CPS IgG2b and IgG2c and generated functional bactericidal antibody titers. CPS-CRM + ALFQ was superior to vaccine alone or CPS-CRM + ALF in augmenting antigen-specific Th1, Th2, and Th17 cytokine responses and a significantly higher proportion of CD4+ IFN-γ+ IL-2+ TNF-α+ and CD4+ IL-4+ IL-10+ T cells. ALFQ also significantly enhanced anti-CPS responses in NHPs when delivered with CPS-CRM compared to alum- or ALF-adjuvanted groups and showed the highest protective efficacy against diarrhea following orogastric challenge with C. jejuni This study provides evidence that the ALF adjuvants may provide enhanced immunogenicity of this and other novel C. jejuni capsule conjugate vaccines in humans.IMPORTANCECampylobacter jejuni is a leading cause of diarrheal disease worldwide, and currently no preventative interventions are available. C. jejuni is an invasive mucosal pathogen that has a variety of polysaccharide structures on its surface, including a capsule. In phase 1 studies, a C. jejuni capsule conjugate vaccine was safe but poorly immunogenic when delivered alone or with aluminum hydroxide. Here, we report enhanced immunogenicity of the conjugate vaccine delivered with liposome adjuvants containing monophosphoryl lipid A without or with QS-21, known as ALF and ALFQ, respectively, in preclinical studies. Both liposome adjuvants significantly enhanced immunity in mice and nonhuman primates and improved protective efficacy of the vaccine compared to alum in a nonhuman primate C. jejuni diarrhea model, providing promising evidence that these potent adjuvant formulations may enhance immunogenicity in upcoming human studies with this C. jejuni conjugate and other malaria and HIV vaccine platforms.
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Vacunas Bacterianas/inmunología , Infecciones por Campylobacter/prevención & control , Inmunogenicidad Vacunal , Lípido A/análogos & derivados , Saponinas/administración & dosificación , Adyuvantes Inmunológicos/administración & dosificación , Animales , Anticuerpos Antibacterianos/sangre , Infecciones por Campylobacter/inmunología , Campylobacter jejuni/inmunología , Citocinas/inmunología , Femenino , Humanos , Inmunoglobulina G/inmunología , Lípido A/administración & dosificación , Liposomas/administración & dosificación , Liposomas/química , Masculino , Ratones , Ratones Endogámicos BALB C , Primates , Células TH1/inmunología , Células Th2/inmunología , Vacunas Conjugadas/administración & dosificaciónRESUMEN
PURPOSE: The etiology of Inflammatory Bowel Disease (IBD) remains currently unknown but evidence would suggest that it results from a complex interplay between genetic susceptibility genes, the intestinal microbiome and the environment, resulting in an increased response towards microbial and self-antigens, followed by the development of pre-clinical intestinal inflammation as a precursor to overt clinical disease. Efforts are needed to provide insights into the characterization of the disease, the possible prediction of complications, and the detection of a pre-clinical disease state where, through early screening and intervention, disease course can be reversed, attenuated or even prevented. A consortium of academic, industry and governmental organization investigators initiated this study to enable an assessment of pre-disease biomarkers in patients newly diagnosed with Crohn's disease (CD) and ulcerative colitis (UC). PARTICIPANTS: A retrospective cohort of 1000 UC and 1000 CD cases with 500 matched controls was drawn from an active duty US military personnel population with relevant inclusion criteria with three associated pre-disease and a single disease-associated archived serum samples. FINDINGS TO DATE: The PREDICTS study has been established as a biorepository platform study to perform novel discovery and analysis efforts in the field of IBD and proteomic systems biology. FUTURE PLANS: This study is poised to enable the assessment of novel biomarkers within the serum compartment to be analyzed with the goal of identifying pre-disease signals that ultimately predict disease risk, and further elucidate disease pathogenesis in the early stages of the disease process, and identify novel exposures that increase disease risk.
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Enterotoxigenic Escherichia coli (ETEC), Campylobacter jejuni (CJ), and Shigella sp. are major causes of bacterial diarrhea worldwide, but there are no licensed vaccines against any of these pathogens. Most current approaches to ETEC vaccines are based on recombinant proteins that are involved in virulence, particularly adhesins. In contrast, approaches to Shigella and CJ vaccines have included conjugate vaccines in which Shigella lipopolysaccharides (LPS) or CJ capsule polysaccharides are chemically conjugated to proteins. We have explored the feasibility of developing a multi-pathogen vaccine by using ETEC proteins as conjugating partners for CJ and Shigella polysaccharides. We synthesized three vaccines in which two CJ polysaccharides were conjugated to two recombinant ETEC adhesins based on CFA/I (CfaEB) and CS6 (CssBA), and LPS from Shigella flexneri was also conjugated to CfaEB. The vaccines were immunogenic in mice as monovalent, bivalent and trivalent formulations. Importantly, functional antibodies capable of inducing hemaglutination inhibition (HAI) of a CFA/I expressing ETEC strain were induced in all vaccines containing CfaEB. These data suggest that conjugate vaccines could be a platform for a multi-pathogen, multi-serotype vaccine against the three major causes of diarrheal disease worldwide.
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Campylobacter jejuni/patogenicidad , Escherichia coli Enterotoxigénica/patogenicidad , Shigella/patogenicidad , Vacunas Conjugadas/uso terapéutico , Animales , Campylobacter jejuni/inmunología , Escherichia coli Enterotoxigénica/inmunología , Ensayo de Inmunoadsorción Enzimática , Pruebas de Inhibición de Hemaglutinación , Ratones , Ratones Endogámicos BALB C , Shigella/inmunologíaRESUMEN
Campylobacter jejuni infections are a leading cause of bacterial food-borne diarrhoeal illness worldwide, and Campylobacter infections in children are associated with stunted growth and therefore long-term deficits into adulthood. Despite this global impact on health and human capital, how zoonotic C. jejuni responds to the human host remains unclear. Unlike other intestinal pathogens, C. jejuni does not harbour pathogen-defining toxins that explicitly contribute to disease in humans. This makes understanding Campylobacter pathogenesis challenging and supports a broad examination of bacterial factors that contribute to C. jejuni infection. Here, we use a controlled human infection model to characterize C. jejuni transcriptional and genetic adaptations in vivo, along with a non-human primate infection model to validate our approach. We found that variation in 11 genes is associated with either acute or persistent human infections and includes products involved in host cell invasion, bile sensing and flagella modification, plus additional potential therapeutic targets. In particular, a functional version of the cell invasion protein A (cipA) gene product is strongly associated with persistently infecting bacteria and we identified its biochemical role in flagella modification. These data characterize the adaptive C. jejuni response to primate infections and suggest therapy design should consider the intrinsic differences between acute and persistently infecting bacteria. In addition, RNA sequencing revealed conserved responses during natural host commensalism and human infections. Thirty-nine genes were differentially regulated in vivo across hosts, lifestyles and C. jejuni strains. This conserved in vivo response highlights important C. jejuni survival mechanisms such as iron acquisition and evasion of the host mucosal immune response. These advances highlight pathogen adaptability across host species and demonstrate the utility of multidisciplinary collaborations in future clinical trials to study pathogens in vivo.