Identification of a Cross-reactive Epitope Widely Present in Lipopolysaccharide from Enterobacteria and Recognized by the Cross-protective Monoclonal Antibody WN1 222-5

Septic shock due to infections with Gram-negative bacteria is a severe disease with a high mortality rate. We report the identification of the antigenic determinants of an epitope that is present in enterobacterial lipopolysaccharide (LPS) and recognized by a cross-reactive monoclonal antibody (mAb WN1 222-5) regarded as a potential means of treatment. Using whole LPS and a panel of neoglycoconjugates containing purified LPS oligosaccharides obtained from Escherichia coli core types R1, R2, R3, and R4, Salmonella enterica, and the mutant strain E. coli J-5, we showed that mAb WN1 222-5 binds to the distal part of the inner core region and recognizes the structural element R1-alpha-d-Glcp-(1-->3)-[l-alpha-d-Hepp-(1-->7)]-l-alpha-d-Hepp 4P-(1-->3)-R2 (where R1 represents additional sugars of the outer core and R2 represents additional sugars of the inner core), which is common to LPS from all E. coli, Salmonella, and Shigella. WN1 222-5 binds poorly to molecules that lack the side chain heptose or lack phosphate at the branched heptose. Also molecules that are substituted with GlcpN at the side chain heptose are poorly bound. Thus, the side chain heptose and the 4-phosphate on the branched heptose are main determinants of the epitope. We have determined the binding kinetics and affinities (KD values) of the monovalent interaction of E. coli core oligosaccharides with WN1 222-5 by surface plasmon resonance and isothermal titration microcalorimetry. Affinity constants (KD values) determined by SPR were in the range of 3.6 x 10-5 to 3.2 x 10-8 m, with the highest affinity being observed for the core oligosaccharide from E. coli F576 (R2 core type) and the lowest KD values for those from E. coli J-5. Affinities of E. coli R1, R3, and R4 oligosaccharides were 5-10-fold lower, and values from the E. coli J-5 mutant were 29-fold lower than the R2 core oligosaccharide. Thus, the outer core sugars had a positive effect on binding

Role of Repetitive Antigen Patterns for Induction of Antibodies Against Antibodies

Antibody responses against antibodies, such as rheumatoid factors, are found in several immunopathological diseases and may play a role in disease pathogenesis. Experience shows that they are usually difficult to induce experimentally. Antibodies specific for immunoglobulin constant regions (anti-allotypic) or for variable regions (anti-idiotypic) have been investigated in animal models; the latter have even been postulated to regulate antibody and T cell responses via network-like interactions. Why and how such anti-antibodies are induced during autoimmune diseases, has remained largely unclear. Because repetitively arranged epitopes in a paracrystalline structure of a viral envelope cross-link B cell receptors efficiently to induce a prompt T-independent IgM response, this study used immune complexes containing viruses or bacteria to evaluate the role of antigen pattern for induction of anti-antibody responses. We present evidence that antibodies bound to strictly ordered, but not to irregularly arranged, antigens dramatically enhance induction of anti-antibodies, already after a single immunization and without using adjuvants. The results indicate a novel link between anti-antibody responses and infectious agents, and suggest a similar role for repetitive self-antigens such as DNA or collagen involved in chronic immunopathological diseases

Detection of Enterobacterial Lipopolysaccharides and Experimental Endotoxemia by Means of an Immunolimulus Assay Using Both SerotypeSpecific and Cross-Reactive Antibodies

The immunolimulus (IML) assay system uses solid-phase endotoxin antibodies to capture lipopolysaccharide (LPS), which is then quantified by a modification of the chromogenic limulus amebocyte lysate (CLAL) method. Monoclonal antibodies (MAbs) reactive with selected 0 antigen serotypes of Escherichia coli (O18) and Salmonella typhimurium (O-9,12), when used in the IML, were shown to be highly specific in detecting their respective endotoxins in purified form and in plasma samples from experimentally infected animals. A murine MAb that was broadly cross-reactive with E. coli, Salmonella, and Shigella endotoxins also proved to be highly effective in the IML assay for capturing LPS molecules from both E. coli and S. typhimurium strains. These results indicate that IML assays can detect smooth-type enterobacterial endotoxins in plasma and suggest that such assays have potential for use in the rapid diagnosis of sepsis and endotoxemia caused by different enterobacterial specie

Enhanced Th17-Cell Responses Render CCR2-Deficient Mice More Susceptible for Autoimmune Arthritis

CCR2 is considered a proinflammatory mediator in many inflammatory diseases such as rheumatoid arthritis. However, mice lacking CCR2 develop exacerbated collagen-induced arthritis. To explore the underlying mechanism, we investigated whether autoimmune-associated Th17 cells were involved in the pathogenesis of the severe phenotype of autoimmune arthritis. We found that Th17 cells were expanded approximately 3-fold in the draining lymph nodes of immunized CCR2−/− mice compared to WT controls (p = 0.017), whereas the number of Th1 cells and regulatory T cells are similar between these two groups of mice. Consistently, levels of the Th17 cell cytokine IL-17A and Th17 cell-associated cytokines, IL-6 and IL-1β were approximately 2–6-fold elevated in the serum and 22–28-fold increased in the arthritic joints in CCR2−/− mice compared to WT mice (p = 0.04, 0.0004, and 0.01 for IL-17, IL-6, and IL-1β, respectively, in the serum and p = 0.009, 0.02, and 0.02 in the joints). Furthermore, type II collagen-specific antibodies were significantly increased, which was accompanied by B cell and neutrophil expansion in CCR2−/− mice. Finally, treatment with an anti-IL-17A antibody modestly reduced the disease severity in CCR2−/− mice. Therefore, we conclude that while we detect markedly enhanced Th17-cell responses in collagen-induced arthritis in CCR2-deficient mice and IL-17A blockade does have an ameliorating effect, factors additional to Th17 cells and IL-17A also contribute to the severe autoimmune arthritis seen in CCR2 deficiency. CCR2 may have a protective role in the pathogenesis of autoimmune arthritis. Our data that monocytes were missing from the spleen while remained abundant in the bone marrow and joints of immunized CCR2−/− mice suggest that there is a potential link between CCR2-expressing monocytes and Th17 cells during autoimmunity

IL-1 and IL-23 Mediate Early IL-17A Production in Pulmonary Inflammation Leading to Late Fibrosis

BACKGROUND: Idiopathic pulmonary fibrosis is a devastating as yet untreatable disease. We demonstrated recently the predominant role of the NLRP3 inflammasome activation and IL-1β expression in the establishment of pulmonary inflammation and fibrosis in mice. METHODS: The contribution of IL-23 or IL-17 in pulmonary inflammation and fibrosis was assessed using the bleomycin model in deficient mice. RESULTS: We show that bleomycin or IL-1β-induced lung injury leads to increased expression of early IL-23p19, and IL-17A or IL-17F expression. Early IL-23p19 and IL-17A, but not IL-17F, and IL-17RA signaling are required for inflammatory response to BLM as shown with gene deficient mice or mice treated with neutralizing antibodies. Using FACS analysis, we show a very early IL-17A and IL-17F expression by RORγt(+) γδ T cells and to a lesser extent by CD4αβ(+) T cells, but not by iNKT cells, 24 hrs after BLM administration. Moreover, IL-23p19 and IL-17A expressions or IL-17RA signaling are necessary to pulmonary TGF-β1 production, collagen deposition and evolution to fibrosis. CONCLUSIONS: Our findings demonstrate the existence of an early IL-1β-IL-23-IL-17A axis leading to pulmonary inflammation and fibrosis and identify innate IL-23 and IL-17A as interesting drug targets for IL-1β driven lung pathology

Low in‑hospital mortality rate in patients with COVID‑19 receiving thromboprophylaxis: data from the multicentre observational START‑COVID Register

Abstract COVID-19 infection causes respiratory pathology with severe interstitial pneumonia and extra-pulmonary complications; in particular, it may predispose to thromboembolic disease. The current guidelines recommend the use of thromboprophylaxis in patients with COVID-19, however, the optimal heparin dosage treatment is not well-established. We conducted a multicentre, Italian, retrospective, observational study on COVID-19 patients admitted to ordinary wards, to describe clinical characteristic of patients at admission, bleeding and thrombotic events occurring during hospital stay. The strategies used for thromboprophylaxis and its role on patient outcome were, also, described. 1091 patients hospitalized were included in the START-COVID-19 Register. During hospital stay, 769 (70.7%) patients were treated with antithrombotic drugs: low molecular weight heparin (the great majority enoxaparin), fondaparinux, or unfractioned heparin. These patients were more frequently affected by comorbidities, such as hypertension, atrial fibrillation, previous thromboembolism, neurological disease,and cancer with respect to patients who did not receive thromboprophylaxis. During hospital stay, 1.2% patients had a major bleeding event. All patients were treated with antithrombotic drugs; 5.4%, had venous thromboembolism [30.5% deep vein thrombosis (DVT), 66.1% pulmonary embolism (PE), and 3.4% patients had DVT + PE]. In our cohort the mortality rate was 18.3%. Heparin use was independently associated with survival in patients aged ≥ 59 years at multivariable analysis. We confirmed the high mortality rate of COVID-19 in hospitalized patients in ordinary wards. Treatment with antithrombotic drugs is significantly associated with a reduction of mortality rates especially in patients older than 59 years

Clinical features and outcomes of elderly hospitalised patients with chronic obstructive pulmonary disease, heart failure or both

Background and objective: Chronic obstructive pulmonary disease (COPD) and heart failure (HF) mutually increase the risk of being present in the same patient, especially if older. Whether or not this coexistence may be associated with a worse prognosis is debated. Therefore, employing data derived from the REPOSI register, we evaluated the clinical features and outcomes in a population of elderly patients admitted to internal medicine wards and having COPD, HF or COPD + HF. Methods: We measured socio-demographic and anthropometric characteristics, severity and prevalence of comorbidities, clinical and laboratory features during hospitalization, mood disorders, functional independence, drug prescriptions and discharge destination. The primary study outcome was the risk of death. Results: We considered 2,343 elderly hospitalized patients (median age 81 years), of whom 1,154 (49%) had COPD, 813 (35%) HF, and 376 (16%) COPD + HF. Patients with COPD + HF had different characteristics than those with COPD or HF, such as a higher prevalence of previous hospitalizations, comorbidities (especially chronic kidney disease), higher respiratory rate at admission and number of prescribed drugs. Patients with COPD + HF (hazard ratio HR 1.74, 95% confidence intervals CI 1.16-2.61) and patients with dementia (HR 1.75, 95% CI 1.06-2.90) had a higher risk of death at one year. The Kaplan-Meier curves showed a higher mortality risk in the group of patients with COPD + HF for all causes (p = 0.010), respiratory causes (p = 0.006), cardiovascular causes (p = 0.046) and respiratory plus cardiovascular causes (p = 0.009). Conclusion: In this real-life cohort of hospitalized elderly patients, the coexistence of COPD and HF significantly worsened prognosis at one year. This finding may help to better define the care needs of this population

Outcomes from elective colorectal cancer surgery during the SARS-CoV-2 pandemic

This study aimed to describe the change in surgical practice and the impact of SARS-CoV-2 on mortality after surgical resection of colorectal cancer during the initial phases of the SARS-CoV-2 pandemic

IL-1R1-MyD88 axis elicits early papain-induced lung inflammation

Allergic asthma is characterized by a strong Th2 response with inflammatory cell recruitment and structural changes in the lung. Papain is a protease allergen disrupting the airway epithelium triggering a rapid inflammation with eosinophilia mediated by innate lymphoid cell activation (ILC2) and leading to a Th2 immune response. In this study, we focused on the early inflammatory responses to papain. A single intranasal administration of papain (25 μg) resulted in the recruitment of inflammatory cells, including neutrophils and eosinophils as well as a rapid production of IL-1, IL-1β, and IL-33. We showed that papain-induced lung inflammation was abrogated in the absence of MyD88. The lack of IL-1R1 recapitulated the effect of MyD88 deficiency. Eosinophilic response was significantly reduced, whereas neutrophils were markedly increased in ST2 deficient mice. IL-36R signaling was devoid of any effect on the inflammatory response. Using cell-specific MyD88 deficient mice we demonstrated that MyD88 signaling in T cells, epithelial cells, CD11c and myeloid cells did not recapitulate the phenotype of MyD88-/- mice indicating that MyD88 expression is necessary in several of these cells or/and other cell types for the development of papain-induced lung inflammation. In conclusion, IL-1R1 signaling via MyD88 is critical for the early inflammatory response to papain