Lectin Levels Research Articles

Transcriptome and proteome profiling reveal complementary scavenger and immune features of rat liver sinusoidal endothelial cells and liver macrophages

BackgroundLiver sinusoidal endothelial cells (LSECs) and Kupffer cells (KCs; liver resident macrophages) form the body’s most effective scavenger cell system for the removal of harmful blood-borne substances, ranging from modified self-proteins to pathogens and xenobiotics. Controversies in the literature regarding the LSEC phenotype pose a challenge when determining distinct functionalities of KCs and LSECs. This may be due to overlapping functions of the two cells, insufficient purification and/or identification of the cells, rapid dedifferentiation of LSECs in vitro, or species differences. We therefore characterized and quantitatively compared expressed gene products of freshly isolated, highly pure LSECs (fenestrated SE-1/FcγRIIb2+) and KCs (CD11b/c+) from Sprague Dawley, Crl:CD (SD), male rats using high throughput mRNA-sequencing and label-free proteomics.ResultsWe observed a robust correlation between the proteomes and transcriptomes of the two cell types. Integrative analysis of the global molecular profile demonstrated the immunological aspects of LSECs. The constitutive expression of several immune genes and corresponding proteins of LSECs bore some resemblance with the expression in macrophages. LSECs and KCs both expressed high levels of scavenger receptors (SR) and C-type lectins. Equivalent expression of SR-A1 (Msr1), mannose receptor (Mrc1), SR-B1 (Scarb1), and SR-B3 (Scarb2) suggested functional similarity between the two cell types, while functional distinction between the cells was evidenced by LSEC-specific expression of the SRs stabilin-1 (Stab1) and stabilin-2 (Stab2), and the C-type lectins LSECtin (Clec4g) and DC-SIGNR (Clec4m). Many immune regulatory factors were differentially expressed in LSECs and KCs, with one cell predominantly expressing a specific cytokine/chemokine and the other cell the cognate receptor, illustrating the complex cytokine milieu of the sinusoids. Both cells expressed genes and proteins involved in antigen processing and presentation, and lymphocyte co-stimulation.ConclusionsOur findings support complementary and partly overlapping scavenging and immune functions of LSECs and KCs. This highlights the importance of including LSECs in studies of liver immunity, and liver clearance and toxicity of large molecule drugs and nano-formulations.

Monitoring and traceability of genetically modified soya bean event GTS 40-3-2 during soya bean protein concentrate and isolate preparation.

To evaluate DNA fragmentation and GMO quantification during soya bean protein concentrate and isolate preparation, genetically modified soya bean event GTS 40-3-2 (Roundup ReadyTM soya bean, RRS) was blended with conventional soya beans at mass percentages of 0.9%, 2%, 3%, 5% and 10%. Qualitative PCR and real-time PCR were used to monitor the taxon-specific lectin and exogenous cp4 epsps target levels in all of the main products and by-products, which has practical significance for RRS labelling threshold and traceability. Along the preparation chain, the majority of DNA was distributed in main products, and the DNA degradation was noticed. From a holistic perspective, the lectin target degraded more than cp4 epsps target during both of the two soya bean proteins preparations. Therefore, the transgenic contents in the final protein products were higher than the actual mass percentages of RRS in raw materials. Our results are beneficial to the improvement of GMO labelling legislation and the protection of consumer rights.

Immune responses upon experimental Erysipelothrix rhusiopathiae infection of na\xefve and vaccinated chickens

Erysipelas, a disease caused by Erysipelothrix rhusiopathiae (ER), is an increasing problem in laying hens housed in cage-free systems. This study aimed to monitor immune responses during ER infection of naïve chickens and chickens vaccinated intra muscularly with a commercial inactivated ER vaccine. Chickens were infected intra muscularly with ER at 30 days of age and blood leukocyte counts, serum levels of mannose binding lectin (MBL) and ER-specific IgY were monitored until the experiment was terminated at day 15 after infection. ER was detected in blood from more chickens and at higher bacterial counts in the naïve group (day 1: 1 of 7 chickens; day 3: 6 of 6 chickens) than in the vaccinated group (day 1: 0 of 7 chickens; day 3: 1 of 6 chickens). During the acute phase of infection transient increases in circulating heterophil numbers and serum MBL levels were detected in all ER infected chickens but these responses were prolonged in chickens from the naïve group compared to vaccinated chickens. Before infection IgY titers to ER in vaccinated chickens did not differ significantly from those of naïve chickens but vaccinated chickens showed significantly increased IgY titers to ER earlier after infection compared to chickens in the naïve group. In conclusion, the ER infection elicited prompt acute innate responses in all chickens. Vaccinated chickens did not have high IgY titers to ER prior to infection but did however show lower levels of bacteraemia and their acute immune responses were of shorter duration.

Levels of mannose-binding lectin (MBL) associates with sepsis-related in-hospital mortality in women

BackgroundMannose-binding lectin (MBL) mediates the innate immune response either through direct opsonisation of microorganisms or through activation of the complement system. There are conflicting data whether MBL deficiency leads to increased susceptibility to infections or not. The aim of this study was to determine if low levels of mannose-binding lectin (MBL) predict sepsis development, sepsis severity and outcome from severe sepsis or septic shock.MethodPatients aged 18 years or more with documented sepsis within 24 h after admission to the intensive care unit were included if they had participated in a health survey and donated blood samples prior to the sepsis event. A subset of these patients had stored plasma also from the acute phase. Two matched referents free of known sepsis were selected for each case. Plasma levels MBL were determined in stored samples from health surveys (baseline) and from ICU admission (acute phase). The association between MBL and sepsis, sepsis severity and in-hospital mortality were determined with 1300 ng/mL as cut-off for low levels.ResultsWe identified 148 patients (61.5% women) with a first-time sepsis event 6.5 years (median with IQR 7.7) after participation in a health survey, of which 122 also had samples from the acute septic phase. Both high MBL levels in the acute phase (odds ratio [95% confidence interval]) (2.84 [1.20–6.26]), and an increase in MBL levels from baseline to the acute phase (3.76 [1.21–11.72]) were associated with increased risk for in-hospital death in women, but not in men (0.47 [0.11–2.06]). Baseline MBL levels did not predict future sepsis, sepsis severity or in-hospital mortality.ConclusionsAn increase from baseline to the acute phase as well as high levels in the acute phase associated with an unfavourable outcome in women.

Mannose‐binding lectin gene polymorphism and its effect on short term outcomes in preterm infants

ObjectiveMannose‐binding lectin, which belongs to the collectin family, is an acute‐phase reactant that activates the complement system. This study aimed to investigate the effect of MBL2 gene polymorphism on short‐term outcomes in preterm infants. MethodInfants of <37 gestational weeks who were admitted to the neonatal intensive care unit during a two‐year period were enrolled in this prospective study. The neonates were categorized into two groups according to their MBL2 genotypes. Normal MBL2 genotype was defined as MBL2 wild‐type (AA genotype), whereas mutant MBL2 genotype was defined as MBL2 variant‐type (AO/OO genotype). The relationship between MBL2 genotype and short‐term morbidity and mortality was evaluated. ResultsDuring the two‐year study period, 116 preterm infants were enrolled in this study. In MBL2 variant‐type, mannose‐binding lectin levels were significantly lower and incidences of mannose‐binding lectin deficiency (MBL level<700ng/mL) were higher (p<0.001). In this group, the prevalence of respiratory distress syndrome and mortality was significantly higher (p<0.001, p=0.03 respectively). In the MBL2 wild‐type group, the prevalence of necrotizing enterocolitis (NEC) was higher (p=0.01). Logistic regression analyses revealed that MBL2 variant‐type had a significant effect on respiratory distress syndrome development (odds ratio, 5.1; 95% confidence interval, 2.2–11.9; p<0.001). ConclusionsMBL2 variant‐type and mannose‐binding lectin deficiency are important risk factors for respiratory distress syndrome development in preterm infants. Additionally, there is an association between MBL2 wild‐type and NEC. Further studies on this subject are needed.

Roles of glycoprotein glycosylation in the pathogenesis of an endemic osteoarthritis, Kashin–Beck disease, and effectiveness evaluation of sodium hyaluronate treatment

Background/aim We aimed to explore the roles of glycoprotein glycosylation in the pathogenesis of Kashin–Beck disease (KBD), and evaluated the effectiveness of sodium hyaluronate treatment. Materials and methods Blood and saliva were collected from KBD patients before and after the injection of sodium hyaluronate. Normal healthy subjects were included as controls. Saliva and serum lectin microarrays and saliva and serum microarray verifications were used to screen and confirm the differences in lectin levels among the three groups. Results In saliva lectin microarray, bindings to Sophora japonica agglutinin (SJA), Griffonia (Bandeiraea) simplicifolia lectin I (GSL-I), Euonymus europaeus lectin (EEL), Maackia amurensis lectin II (MAL-II), Sambucus nigra lectin (SNA), Hippeastrum hybrid lectin (HHL), and Aleuria aurantia lectin (AAL) were higher in the untreated KBD patients than in the control group. Increased levels of HHL, MAL-II, and GSL-I in the untreated KBD patients discriminated them in particular from the treated ones. Jacalin was lower in the untreated KBD patients compared to the treated KBD and control groups. In serum lectin microarray, HHL and peanut agglutinin (PNA) were increased in the untreated KBD group in comparison to the control one. AAL, Phaseolus vulgaris agglutinin (E+L) (PHA-E+L), and Psophocarpus tetragonolobus lectin I (PTL-I) were lower in the untreated KBD patients compared to the treated KBD and control groups. Hyaluronate treatment appeared to normalize SNA, AAL, and MAL-II levels in saliva, and HHL, PNA, AAL, PTL-I, and PHA-E+L levels in serum. Saliva reversed microarray verification confirmed significant differences between the groups in SNA and Jacalin, in particular for GSL-I levels, while serum reversed microarray verification indicated that HHL, PNA, and AAL levels returned to normal levels after the hyaluronate treatment. Lectin blot confirmed significant differences in HHL, AAL, and Jacalin in saliva, and HHL, PNA, PHA-E+L, and AAL in serum. Conclusion HHL in saliva and serum may be a valuable diagnostic biomarker of KBD, and it may be used as follow-up for the hyaluronate treatment.

Effects of a Sudden Drop in Salinity on Scapharca subcrenata Antioxidant Defenses and Metabolism Determined Using LC-MS Non-targeted Metabolomics

In this experiment, the effects of a sudden drop in salinity on the antioxidant defense system and related gene expression of the ark shell Scapharca subcrenata were examined. The sudden drop in seawater salinity after a rainstorm was simulated, and subsequently differentially expressed metabolic markers were identified by LC-MS non-targeted metabolomics. When the salinity dropped to 14‰ (S14), the total anti-oxidant content, activity of Na+/K+-ATPase, superoxide dismutase (SOD), and catalase (CAT), content of malondialdehyde, and expression levels of Mn-SOD, CAT, and C-type lectin of S. subcrenata were significantly higher than in groups with salinity of 22‰ (S22) or 30‰ (S30) (P < 0.05). The activity of glutathione peroxidase (GPx), the content of reduced glutathione, and the expression levels of GPx were not significantly different between S14 and S22, but the values in each group were significantly higher than those in S30 (P < 0.05). Using the metabolomics technique, 361, 271, and 264 metabolites with significant differences were identified from S22 vs. S14, S30 vs. S14, and S30 vs. S22, respectively. The drop in salinity was accompanied by up-regulation of phosphatidylcholine (PC) (20:4 (5Z, 8Z, 11Z, 14Z)/P-18: 1 (11Z)), PC (16:0/22: 6 (4Z, 7Z, 10Z, 13Z, 16Z, 19Z)), phosphatidylethanolamine (PE) (18:4 (6Z, 9Z, 12Z, 15Z)/24:1 (15Z)), phosphatidylinositol (PI) (20:1 (11Z)/0:0), phalluside-1, C16 sphinganine, and LacCer (d18:0/14:0) and by significant down-regulation of PI-Cer (d18:1/14:0) and PE (14:0/16:1(9Z). The results of this study illustrate how these nine metabolites can be used as metabolic markers for the response of S. subcrenata to a sudden drop in salinity. They also provide the theoretical groundwork for selection of bottom areas with salinity that is optimal for release and proliferation of S. subcrenata, which is needed to restore the declining populations of this species.

Complement profile in microscopic polyangiitis and granulomatosis with polyangiitis: analysis using sera from a nationwide prospective cohort study

Objective The complement cascade, especially the alternative pathway of complement, has been shown in basic research to be associated with anti-neutrophil cytoplasmic autoantibody (ANCA)-associated vasculitis (AAV). We aimed to elucidate relationships between serum complement components and clinical characteristics in AAV. Method In a nationwide prospective cohort study (RemIT-JAV-RPGN), we measured the serum levels of C1q, C2, C3, C3b/iC3b, C4, C4b, C5, C5a, C9, factor B, factor D, factor H, factor I, mannose-binding lectin, and properdin in 52 patients with microscopic polyangiitis (MPA) and 39 patients with granulomatosis with polyangiitis (GPA). Results The properdin level of MPA and GPA was significantly lower than that of healthy donors. The properdin level was negatively correlated with the Birmingham Vasculitis Activity Score (BVAS) (ρ = −0.2148, p = 0.0409). The factor D level at 6 months was significantly positively correlated with the Vasculitis Damage Index (VDI) at 6, 12, and 24 months (ρ = 0.4207, 0.4132, and 0.3115, respectively). Patients with a higher ratio of C5a to C5 had higher neutrophil percentage and serum immunoglobulin G levels, and significantly lower creatinine levels. Cluster analysis divided the MPA and GPA patients into three subgroups. A principal component (PC) analysis aggregated 15 types of complements into alternative pathway-related PC 1 and complement classical pathway and common pathway-related PC 2. Conclusions The serum levels of properdin and factor D were correlated with the BVAS and the VDI in MPA and GPA, respectively. Our analyses suggested the pathological heterogeneity of MPA and GPA from the aspect of complement components.

Toxoplasma gondii Recruits Factor H and C4b-Binding Protein to Mediate Resistance to Serum Killing and Promote Parasite Persistence in vivo.

Regulating complement is an important step in the establishment of infection by microbial pathogens. Toxoplasma gondii actively resists complement-mediated killing in non-immune human serum (NHS) by inactivating C3b, however the precise molecular basis is unknown. Here, a flow cytometry-based C3b binding assay demonstrated that Type II strains had significantly higher levels of surface-bound C3b than Type I strains. However, both strains efficiently inactivated C3b and were equally resistant to serum killing, suggesting that resistance is not strain-dependent. Toxoplasma activated both the lectin (LP) and alternative (AP) pathways, and the deposition of C3b was both strain and lectin-dependent. A flow cytometry-based lectin binding assay identified strain-specific differences in the level and heterogeneity of surface glycans detected. Specifically, increased lectin-binding by Type II strains correlated with higher levels of the LP recognition receptor mannose binding lectin (MBL). Western blot analyses demonstrated that Toxoplasma recruits both classical pathway (CP) and LP regulator C4b-binding proteins (C4BP) and AP regulator Factor H (FH) to the parasite surface to inactivate bound C3b–iC3b and C3dg and limit formation of the C5b-9 attack complex. Blocking FH and C4BP contributed to increased C5b-9 formation in vitro. However, parasite susceptibility in vitro was only impacted when FH was blocked, indicating that down regulation of the alternative pathway by FH may be more critical for parasite resistance. Infection of C3 deficient mice led to uncontrolled parasite growth, acute mortality, and reduced antibody production, indicating that both the presence of C3, and the ability of the parasite to inactivate C3, was protective. Taken together, our results establish that Toxoplasma regulation of the complement system renders mice resistant to acute infection by limiting parasite proliferation in vivo, but susceptible to chronic infection, with all mice developing transmissible cysts to maintain its life cycle.

A novel C-type lectin with a YPD motif from Portunus trituberculatus (PtCLec1) mediating pathogen recognition and opsonization

C-type lectins are a superfamily of Ca2+-dependent carbohydrate-recognition proteins that function as pattern recognition receptors (PRRs) in innate immune system. In this study, a new C-type lectin was identified from the swimming crab Portunus trituberculatus (PtCLec1). The full-length cDNA of PtCLec1 was 873 bp encoding 176 amino acids. The predicted PtCLec1 protein contained a signal peptide and a single carbohydrate-recognition domain with a special YPD motif. The PtCLec1 transcripts were mainly detected in hepatopancreas and its relative expression levels were significantly up-regulated after the challenges of Vibrio alginolyticus, Micrococcus luteus and Pichia pastoris. The recombinant PtCLec1 (rPtCLec1) could bind all the tested pathogen-associated molecular patterns (PAMPs), including lipopolysaccharides (LPS), peptidoglycan (PGN) and glucan (GLU), and microorganisms, including V. alginolyticus, V. parahaemolyticus, Pseudomonas aeruginosa, Staphylococcus aureus, M. luteus and P. pastoris. It also exhibited strong activity to agglutinate bacteria and yeast in a Ca2+-dependent manner, and such agglutinating activity could be inhibited by d-galactose and LPS. Moreover, rPtCLec1 revealed antimicrobial activity against the tested Gram-negative (V. alginolyticus, V. parahaemolyticus and P. aeruginosa) and Gram-positive bacteria (S. aureus and M. luteus), and promoted the clearance of V. alginolyticus in vivo and hemocyte phagocytosis in vitro. Knockdown of PtCLec1 could down-regulate the expression of phagocytosis-related genes, but enhance the expression levels of prophenoloxidase (proPO) system-related genes, mannose-binding lectin (MBL), antimicrobial peptides (AMPs), MyD88 and Relish. All these results indicate that PtCLec1 might act as a PRR in immune recognition and an opsonin in pathogen elimination.

Serum Mannose-Binding Lectin Levels Are Correlated with the Disease Activity of Antineutrophil Cytoplasmic Antibody-Associated Vasculitis: A Single-Center Study.

Mannose-binding lectin (MBL) is a soluble pattern-recognition molecule, which plays a crucial role in the innate immune system and the activation of lectin complement pathway. Antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV) is an autoimmune disease affecting the small vasculatures and is characterized by the alteration of innate and adaptive immunity and complement activation. In this study, we investigated whether serum MBL is associated with disease activity of AAV, which was measured by ELISA. Associations between serum MBL and AAV-specific indices, as well as clinical and laboratory data were assessed using Kendall's tau. Among the 80 patients, 42 (52.5%), 21 (26.3), and 17 (21.3%) patients were classified as microscopic polyangiitis (MPA), granulomatosis with polyangiitis (GPA), and eosinophilic granulomatosis with polyangiitis (EGPA), respectively. The median values of erythrocyte sedimentation rate, C-reactive protein, and serum MBL were 36.5 (normal range < 20) mm/h, 2.4 (normal range < 8) mg/dL, and 8.6 ng/mL, respectively. The median serum levels of MBL in MPA, GPA, and EGPA patients were 8.4, 9.3, and 8.2 ng/mL. Correlation analysis showed that serum MBL was associated with Birmingham Vasculitis Activity Score (BVAS) (R = 0.169, p = 0.027), but not with other AAV-specific indices and clinical and laboratory data. In addition, serum MBL was significantly associated with the pulmonary manifestation score based on BVAS (R = 0.247, p = 0.001). In summary, among the AAV-specific indices and clinical and laboratory variables analyzed, serum MBL is correlated with BVAS and pulmonary manifestation score based on the BVAS.

Complement activation by autoantigen recognition in the growth process of benign prostatic hyperplasia

The pathophysiology of benign prostatic hyperplasia (BPH) remained unclear. Here, we concentrated on the complement activation in the growth of BPH using a rat model. BPH tissues were harvested from rats after rat urogenital sinus implantation. The local expression and deposition levels of C1q, C3, mannose-binding lectin (MBL), factor B (FB), and C5b-9 in the rat and human BPH tissues were analyzed by real-time RT-PCR, western blotting and immunohistochemistry (IHC). Serum IgG levels in the rat BPH model were analyzed by ELISA, and IHC was used to assess tissue localization. Proteins binding serum IgG autoantibody in the BPH rats were isolated by immunoprecipitation. C1q, C3, MBL, FB and C5b-9 were highly localized in rat BPH tissues compared to normal tissues. In contrast, C3, FB and C5b-9, but not C1q and MBL, were abundantly detected in human BPH tissues compared to normal tissues. Diffuse localization of IgG in rat BPH tissues was found. Heat shock protein 90, annexin, α-smooth muscle actin, and β-actin were identified as targets for IgG autoantibodies in the BPH model. Our results strongly suggested the role for complement activation in the growth process of BPH, likely triggered by classical pathway activation with autoantibodies.

Low pre-transplant levels of mannose-binding lectin are associated with viral infections and mortality after haematopoietic allogeneic stem cell transplantation

BackgroundMannose-binding lectin (MBL) is a key component of innate immunity. Low serum MBL levels, related to promoter polymorphism and structural variants, have been associated with an increased risk of infection. The aim of this work was to analyse the incidence and severity of infections and mortality in relation to the MBL2 genotype and MBL levels in patients underwent allogeneic haematopoietic stem cell transplantation (Allo-HSCT).ResultsThis was a prospective cohort study of 72 consecutive patients underwent Allo-HSCT between January 2007 and June 2009 in a tertiary referral centre. Three periods were considered in the patients’ follow-up: the early period (0–30 days after Allo-HSCT), the intermediate period (30–100 days after Allo-HSCT) and the late period (> 100 days after Allo-HSCT). A commercial line probe assay for MBL2 genotyping and an ELISA Kit were used to measure MBL levels. A total of 220 episodes of infection were collected in the 72 patients. No association between donor or recipient MBL2 genotype and infection was found. The first episode of infection presented earlier in patients with pre-transplant MBL levels of < 1000 ng/ml (median 6d vs 8d, p = 0.036). MBL levels < 1000 ng/ml in the pre-transplant period (risk ratio (RR) 2.48, 95% CI 1.00–6.13), neutropenic period (0–30 days, RR 3.28, 95% CI 1.53–7.06) and intermediate period (30–100 days, RR 2.37, 95% CI 1.15–4.90) were associated with increased risk of virus infection. No association with bacterial or fungal disease was found. Mortality was associated with pre-transplant MBL levels < 1000 ng/ml (hazard ratio 5.55, 95% CI 1.17–26.30, p = 0.03) but not with MBL2 genotype.ConclusionsPatients who underwent Allo-HSCT with low pre-transplant MBL levels presented the first episode of infection earlier and had an increased risk of viral infections and mortality in the first 6 months post-transplant. Thus, pre-transplant MBL levels would be important in predicting susceptibility to viral infections and mortality and might be considered a biomarker to be included in the pre-transplantation risk assessment.

Mannose-Binding Lectin Levels in Late-Onset Sepsis in Preterm Infants: Results from a Prospective Study in a Tertiary Care Center

Introduction: This study aimed to determine the association between serum mannose-binding lectin (MBL) levels, gene polymorphisms and late-onset sepsis (LOS) in preterm infants. Methods: Infants with <37 gestational weeks were categorized into two groups according to the presence of LOS during their hospitalization. An MBL level <700 ng/ml was defined as deficiency, <400 ng/ml as severe deficiency. Codon 54 and 57 polymorphisms of MBL2 gene were analyzed. Results: Overall, 153 preterm infants were included. MBL deficiency was found to be more common in the LOS group (p = 0.02). The rate of Gram-negative sepsis was higher in MBL2 variant-type (p = 0.01). In the logistic regression analysis, MBL levels <700 ng/ml were found to have a significant effect on LOS development (odds ratio: 2.692, 95% confidence interval 1.196–5.8, p = 0.02). Conclusions: MBL deficiency is an important risk factor for the development of LOS. Furthermore, there is an association between MBL2 gene polymorphism and Gram-negative sepsis.

Inflammatory Bowel Disease Types Differ in Markers of Inflammation, Gut Barrier and in Specific Anti-Bacterial Response.

Crohn’s disease (CD), ulcerative colitis (UC) and inflammatory bowel disease (IBD) associated with primary sclerosing cholangitis (PSC-IBD), share three major pathogenetic mechanisms of inflammatory bowel disease (IBD)-gut dysbiosis, gut barrier failure and immune system dysregulation. While clinical differences among them are well known, the underlying mechanisms are less explored. To gain an insight into the IBD pathogenesis and to find a specific biomarker pattern for each of them, we used protein array, ELISA and flow cytometry to analyze serum biomarkers and specific anti-microbial B and T cell responses to the gut commensals. We found that decrease in matrix metalloproteinase (MMP)-9 and increase in MMP-14 are the strongest factors discriminating IBD patients from healthy subjects and that PSC-IBD patients have higher levels of Mannan-binding lectin, tissue inhibitor of metalloproteinases 1 (TIMP-1), CD14 and osteoprotegerin than patients with UC. Moreover, we found that low transforming growth factor-β1 (TGF-β1) is associated with disease relapse and low osteoprotegerin with anti-tumor necrosis factor-alpha (TNF-α) therapy. Patients with CD have significantly decreased antibody and increased T cell response mainly to genera Eubacterium, Faecalibacterium and Bacteroides. These results stress the importance of the gut barrier function and immune response to commensal bacteria and point at the specific differences in pathogenesis of PSC-IBD, UC and CD.

Production and application of monoclonal antibodies against C-type lectins in scallop Chlamys farreri

C-type lectins, as types of pattern recognition receptors (PRRs), have crucial roles in innate immunity, and their conserved carbohydrate recognition domain (CRD) is recognized as the binding dominant to pathogen-associated molecular patterns (PAMPs). In this study, a C-type lectin in the scallop Chlamys farreri (lectin B, GenBank No. DQ209290) was heterologously expressed and the recombinant protein (rlectin B) with a molecular mass of approximately 42 kDa was purified. The rlectin B protein could induce the aggregation of Escherichia coli, Vibrio anguillarum and Staphylococcus aureus. Six monoclonal antibodies (mAbs) against rlectin B was developed, among which two mAbs (1A7 and 2B6) could react with the gills, hepatopancreas, adductor muscle, and haemocytes of C. farreri by indirect immunofluorescence assay and bound to proteins with molecular masses of 21, 28, 37, 45, 58, and 70 kDa in western blot assays. Using the two mAbs, C-type lectins protein levels were detected in C. farreri haemocytes after V. anguillarum infection, showing that that lectin levels rapidly increased, peaking at 12 h before gradually decreasing to the control group levels. Furthermore, the FACS results also confirmed that V. anguillarum infection significantly increasing C-type lectins expression in haemocytes. These data suggest that the mAbs can recognize various C-type lectins in C. farreri and are a useful immunological tool for the detection C-type lectins in scallops.

Mannose-binding lectin gene polymorphism and its effect on short term outcomes in preterm infants

ObjectiveMannose-binding lectin, which belongs to the collectin family, is an acute-phase reactant that activates the complement system. This study aimed to investigate the effect of MBL2 gene polymorphism on short-term outcomes in preterm infants. MethodInfants of <37 gestational weeks who were admitted to the neonatal intensive care unit during a two-year period were enrolled in this prospective study. The neonates were categorized into two groups according to their MBL2 genotypes. Normal MBL2 genotype was defined as MBL2 wild-type (AA genotype), whereas mutant MBL2 genotype was defined as MBL2 variant-type (AO/OO genotype). The relationship between MBL2 genotype and short-term morbidity and mortality was evaluated. ResultsDuring the two-year study period, 116 preterm infants were enrolled in this study. In MBL2 variant-type, mannose-binding lectin levels were significantly lower and incidences of mannose-binding lectin deficiency (MBL level<700ng/mL) were higher (p<0.001). In this group, the prevalence of respiratory distress syndrome and mortality was significantly higher (p<0.001, p=0.03 respectively). In the MBL2 wild-type group, the prevalence of necrotizing enterocolitis (NEC) was higher (p=0.01). Logistic regression analyses revealed that MBL2 variant-type had a significant effect on respiratory distress syndrome development (odds ratio, 5.1; 95% confidence interval, 2.2–11.9; p<0.001). ConclusionsMBL2 variant-type and mannose-binding lectin deficiency are important risk factors for respiratory distress syndrome development in preterm infants. Additionally, there is an association between MBL2 wild-type and NEC. Further studies on this subject are needed.

High levels of urinary complement proteins are associated with chronic renal damage and proximal tubule dysfunction in immunoglobulin A nephropathy.

Complement activation is involved in the pathogenesis and progression of immunoglobulin A nephropathy (IgAN); however, the clinical implication of abnormal complement protein levels in serum and urine is not clear. To address this we analyzed the correlation between disease activity and complement proteins in serum and urine from IgAN patients, and compared to patients with other types of chronic kidney disease (CKD) as well as healthy controls. We included 85 Chinese patients with IgAN, 23 patients with non-proliferative CKD, and 20 healthy individuals. Patients were divided according to the Oxford classification of M0E0S0T0 (group 1, n = 20), M1E1S0-1 T0-1 (group 2, n = 25), M1E1S0-1 T2 or M0E0S1T1-2 (group 3, n = 40). Complement factor H (CFH), mannose-binding lectin and membrane attack complex in serum and urine were measured by enzyme-linked immunosorbent assay. Urinary CFH, membrane attack complex and serum CFH were increased in both IgAN and CKD patients compared with healthy controls. The urinary excretion of CFH was the highest in IgAN patients with most tubulointerstitial damage (IgAN group 3). Urinary CFH and mannose-binding lectin levels were significantly higher in IgAN patients with crescents formation (C1-2) than in patients without (C0). Urinary complement protein excretion correlated negatively with estimated glomerular filtration rate, and positively with urinary retinol-binding protein and α1-microglobulin excretion indicating proximal tubule dysfunction. Increased urinary excretion of complement proteins in IgAN is related to chronic injury and tubular dysfunction. This warrants caution using urinary complement proteins as markers of disease activity.

Possible Role of Chitin‐Like Proteins in the Etiology of Alzheimer's Disease

Chitin is a β‐linked straight chain carbohydrate matrix monopolymer prominent in invertebrates, from fungi to arthropods. Surprisingly, chitin is now documented in vertebrates, including humans, a component of vertebrate physiology that has been neglected until now. Chitin levels are elevated in Alzheimer's disease (AD) patients, not only in the central nervous system but also in the cerebrospinal fluid and plasma. Elevated levels of chitin lectin have been reported in patients with AD. Chitinase activity varies widely in the human population. Chitin levels can increase in individuals with intrinsically low chitinase activity. Elevated amounts of chitin can reflect accumulation of the small chitin fragments that remain wherever rapid hyaluronan synthesis occurs. Another source of chitin may be from remote fungal infections. Chitin can be toxic for neurons, and its accumulation may lead to the development of AD. We present new suggestions for animal models and treatment modalities that could prove useful in future research endeavors. An unexpected connection with Gaucher's disease patients and their heterozygote relatives is also identified. These chitin‐related mechanisms are novel approaches to AD whose etiology until now has defied explication.This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

Characterization of small GTPase Rac1 and its interaction with PAK1 in crayfish Procambarus clarkii

Ras-related C3 botulinum toxin substrate 1 (Rac1) participates in many biological processes. In this study, a Rac1 gene was identified in the crayfish Procambarus clarkii with an open reading frame of 579 bp that encoded 192 amino acids. This predicted 21.4 kDa protein was highly homologous to those in other invertebrates. Real-time PCR analysis revealed that Pc-Rac1 was expressed in all examined tissues with the highest expression level in hemocytes. The transcriptional expression level of Pc-Rac1 was significantly upregulated in hemocytes and hepatopancreas after lipopolysaccharide (LPS) or polyinosinic: polycytidylic acid (poly I: C) induction. Sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) and western blot analysis suggested that a recombinant Pc-Rac1 protein was successfully expressed in E. coli. Far-western blot analysis demonstrated that Rac1 can interact with the PBD domain of p21-activated kinase 1 (PAK1). RNA interference of Pc-Rac1 affected the mRNA expression levels of immune-related genes lectin, Toll, crustin, TNF, ALF and cactus. These results suggest that Pc-Rac1 is involved in the innate immune responses in P. clarkii.