Mannose-binding Lectin Expression Research Articles

P139 A potential protective rule of Mannose Binding lectin (MBL) against SARS-COV2 infection in IBD patients

Abstract Background Since the beginning of the COVID-19 pandemic, IBD patients have appeared to be less susceptible to a severe form of the disease, despite undergoing immunosuppressive treatments. Mannose binding lectin (MBL) is a humoral fluid-phase pattern recognition molecule (PRM) crucial for activating the lectin complement pathway. It is capable of binding to the spike protein and blocking SARS-CoV-2 infection. Low MBL expression has been linked to poor outcomes in both SARS and SARS- CoV-2 infections. In IBD patients, the role of MBL is controversial; low concentrations seem to predispose individuals to the development of IBD, while high concentrations have been observed in severe forms of Crohn's disease. Methods Since April 2020, 104 IBD patients have been enrolled, with 20% treated with mesalazine, 50% with Anti-TNFa, 20% with Vedolizumab, and 20% receiving no treatment. Additionally, 45 healthy controls (HC) from North Italy were included. Serum samples and colon biopsies from inflamed and non- inflamed mucosa were collected. Serum samples underwent an ELISA test to quantify circulating MBL concentration, and MBL gene expression in biopsies was analyzed using qPCR. Results Both Crohn's disease and Ulcerative Colitis patients exhibited significantly higher circulating MBL levels than HC (411.6 ± 45.5 ng/ml vs. 160.9 ± 35.3 ng/ml, p < 0.05). Patients treated with Anti-TNFa showed significantly higher circulating MBL levels compared to those not undergoing therapy (530.1 ± 76.5 ng/ml vs. 225.4 ± 61.6 ng/ml, p < 0.05) and patients receiving Vedolizumab (530.1 ± 76.5 ng/ml vs. 155.3 ± 32.1 ng/ml, p < 0.05). MBL intestinal gene expression is higher in IBD patients than HC (5.55 ± 0.9 vs. 2.36 ± 0.6; p=0.591) and tended to be elevated at similar levels in inflamed and non-inflamed mucosa (5.14 ± 1.4 vs. 5.79 ± 1.1; p=0.337), suggesting a prevalent genetic determination of MBL concentration regardless of the inflammatory background. Conclusion MBL appears to play a key role in SARS-CoV-2 infection. We demonstrate that IBD patients have, on average, higher circulating MBL levels than HC independently of their inflammatory status. The highest MBL levels were observed in patients treated with Anti-TNFa. These findings contribute to understanding the reported low mortality and hospitalization for COVID-19 among IBD patients treated with Anti-TNFa.

A novel tumor necrosis factor receptor-associated factor 6 (TRAF6) gene from Macrobrachiumrosenbergii involved in antibacterial defense against Aeromonas hydrophila.

Tumor necrosis factor receptor-associated factor 6 (TRAF6) is an adapter protein that triggers downstream cascades mediated by both TNFR and the interleukin-1 receptor/Toll-like receptor (IL-1R/TLR) superfamily. TRAF6 is involved in various biological processes, including innate and adaptive immunity. In the present study, a homolog of TRAF6 from Macrobrachium rosenbergii (MrTRAF6) was identified and characterized. The full-length cDNA of MrTRAF6 consisted of 2,114 nucleotides with an open reading frame (ORF) of 1,695 nucleotides encoding a 564-amino acid protein that contained a conserved TRAF family motif including two RING-type zinc fingers and a C-terminal meprin and TRAF homology (MATH) domain. The putative amino sequence of MrTRAF6 shared 45.5-97.3% identity with TRAF6s from other crustacean species with the highest identity to Macrobrachium nipponense TRAF6. Phylogenetic analysis revealed that MrTRAF6 was closely related to TRAF6 of invertebrates and clustered with crustaceans. According to gene expression analysis, the MrTRAF6 transcript demonstrated broad expression in all tissues tested, with the highest expression level in gill and the lowest in muscle tissues. Upon immune challenge with Aeromonas hydrophila, significant upregulation of MrTRAF6 expression was found in the gill, hepatopancreas, hemocyte, and muscle. Furthermore, an RNA interference assay showed that silencing MrTRAF6 by dsRNA could reduce the expression of mannose-binding lectin (MBL) and crustin, but no significant change was detected in anti-lipopolysaccharide factor 5 (ALF5) levels. In addition, the cumulative mortality rate of MrTRAF6-silenced M. rosenbergii was significantly increased after A. hydrophila infection. These findings indicated that MrTRAF6 is involved in antibacterial activity and plays a critical role in the innate immune response of M. rosenbergii.

Importance of mannose-binding lectin2 polymorphism (rs1800450) in infections in children

Purpose Mannose-binding lectin (MBL) is a serine protease belonging to the collectins and an important factor in the inherited immune system. We aimed to reveal the distribution of different MBL2 genotypes in patients diagnosed with acute bronchiolitis and pneumonia. Material and methods A total of 147 patients who applied to Paediatric Emergency between 01.12.2019 and 31.12.2020 were included in the study. Patients were divided into two subgroups: Bronchiolitis and pneumonia. Results AA genotype was found to be significantly higher in healthy controls (p = 0.039). In the pneumonia group, both AB/BB genotype was significantly higher compared to healthy controls (p = 0.001). While the AA genotype was more common in patients with acute bronchiolitis, AB/BB genotypes were more common in the pneumonia group (p = 0.001). The presence of fever, crepitation, tachypnoea, pathological x-ray finding, and high leukocyte count are significantly more common in patients with AA genotype, while more than 3 days of follow-up duration and severe clinical picture were more common in patients with AB/BB genotypes (p < 0.05, for all). Conclusions Genotypes with low MBL expression were significantly more common in patients with pneumonia and severe infection. All these results reveal the importance of MBL polymorphisms and their expression in infections.

Mannose-Binding Lectin and Risk of Cardiovascular Events and Mortality in Type 2 Diabetes: A Danish Cohort Study.

Mannose-binding lectin (MBL) is linked to risk of cardiovascular disease (CVD) in diabetes, but the nature of the association is unclear. We investigated the association between MBL and the risk of cardiovascular events (CVE) and all-cause mortality in type 2 diabetes. In a cohort study of 7,588 patients with type 2 diabetes, we measured serum MBL in 7,305 patients and performed MBL expression genotyping in 3,043 patients. We grouped serum MBL and MBL expression genotypes into three categories: low, intermediate, and high. Outcomes were CVE (myocardial infarction, stroke, coronary revascularization, unstable angina, or cardiovascular death) and all-cause mortality. The association with outcomes was examined by spline and Cox regression analyses. Serum MBL and CVE showed a U-shaped association. Compared with the intermediate serum MBL category, the adjusted hazard ratio (HR) for CVE was 1.82 (95% CI 1.34-2.46) for the low-MBL category and 1.48 (95% CI 1.14-1.92) for the high-MBL category. We found a similar U-shaped association for all-cause mortality, but with lower risk estimates. Compared with the intermediate MBL expression genotype, the adjusted HR for CVE was 1.40 (95% CI 0.87-2.25) for the low-expression genotype and 1.44 (95% CI 1.01-2.06) for the high-expression genotype. MBL expression genotype was not associated with all-cause mortality. Both serum MBL and MBL expression genotype showed a U-shaped association with CVE risk in individuals with type 2 diabetes. Our findings suggest that serum MBL is a risk factor for CVD in this population.

Impact of mannose-binding lectin 2 gene polymorphisms on disease severity in noncystic fibrosis bronchiectasis in children.

Mannose-binding lectin (MBL) is a complement protein involved in the innate immune system, and is associated with some chronic respiratory diseases including noncystic fibrosis (non-CF) bronchiectasis in adults. The aim of this study was to investigate the frequency of MBL2 gene polymorphisms in children with non-CF bronchiectasis, and the effect of MBL deficiency on disease severity. Fifty children with non-CF bronchiectasis (bronchiectasis group) and 50 healthy controls (control group) were included. The demographic findings, number of acute pulmonary exacerbations in the previous year, airway cultures, pulmonary function tests, and radiologic scores of the bronchiectasis group were recorded. DNA extraction was performed in both groups and MBL2 gene polymorphisms in codons 52, 54, 57 in exon 1 and H/L, Y/X in the promoter region were studied using real-time polymerase chain reaction. Haplotypes were made by genotypes, and MBL serum expression was classified according to the genotypes in the literature. The bronchiectasis group consisted of 23 (46%) patients with primary ciliary dyskinesia, 5 (10%) with primary immunodeficiency diseases, and 22 (44%) with idiopathic bronchiectasis. There were no statistically significant differences between the bronchiectasis and control groups in terms of allele and genotype frequencies of polymorphisms in codons 52, 54, 57 in exon 1 and promoter H/L. However, the YX heterozygote genotype was more frequent in the control group (82%) compared with the bronchiectasis group (50%) (P = .002). The frequency of patients with intermediate serum MBL expression genotype was higher in the bronchiectasis group (20%) than in the control group (0%) (P = .001). In the bronchiectasis group, there were no significant differences in growth, annual pulmonary exacerbation rates in the last year, pulmonary function tests, radiologic scores, and microbiologic findings between low, intermediate, and high-expressing genotypes. In children with non-CF bronchiectasis, MBL genotype was different from healthy controls. MBL deficiency associated only with MBL genotype was not related to disease severity in this group of patients.

Hepatic TLR4, MBL and CRP gene expression levels are associated with chronic hepatitis C

Contact with HCV triggers the activation of innate mechanisms responsible for initial infection control. Host cells expressed extra- or intracellularly molecules that promote recognition of pathogen-associated molecular patterns (PAMPs). Toll-like receptor 4 (TLR4), mannose-binding lectin (MBL) and C-reactive protein (CRP) are molecules available for HCV PAMP recognition. The present study evaluated TLR4, MBL and CRP gene expression in the hepatic tissue of chronic HCV carriers (n = 22) and the association of that expression with the pathogenesis of HCV as well as the progression of liver fibrosis. Liver biopsy specimens from the HCV group were divided according to the METAVIR classification: without fibrosis and/or mild fibrosis (F0-F1), moderate fibrosis (F2), and severe fibrosis and/or cirrhosis (F3-F4) and A0-A1 (absent or mild inflammation) and A2 (moderate inflammation); normal liver samples were used as a control (n = 8). The mRNA levels of the genes studied were quantified by real-time PCR, and plasma CRP and liver enzymes were measured using an automated system. CRP and MBL expression was significantly lower in the HCV group compared to that in the control group (p < .0001 and p = .0242, respectively). TLR4 expression was higher in the HCV group than in the control group (p = .0448) and was also significantly higher (p = .0314) with lower levels of necroinflammatory activity (A0-A1), with a significant correlation between the expression of MBL with TLR4 as well as a positive correlation between plasma levels and CRP expression in the HCV group (p = .0431). Hepatic TLR4, MBL and CRP expression showed no significant association with liver enzymes nor plasma viral load. Mechanisms of HCV escape seem to influence hepatic TLR4, MBL and CRP expression, resulting in a change in the transcription profile of these proteins of innate immunity, which may contribute to virus persistence, liver fibrogenesis and loss of normal liver function.

High Expression of Complement Components in the Kidneys of Type 2 Diabetic Rats With Diabetic Nephropathy.

Background: Diabetic nephropathy (DN) is the leading cause of end-stage failure of the kidneys; however, its pathogenesis remains unknown. This study assessed the expression of complement components in the kidneys of rats with type 2 DN to investigate their role in DN.Methods: A rat model of type 2 DN was induced by a high-fat diet combined with low-dose streptozotocin. Blood glucose, fasting insulin levels, insulin resistance index, and 24-h urinary albumin excretion (UAE) were measured. Renal tissue morphological features were observed. The mesangial index and arteriosclerosis index were calculated. Immunohistochemistry and western blot were used to measure the expression of complement components in the kidneys.Results: The kidney weight: body weight (mg/g) ratio in the DN group was significantly greater than those in the control and diabetes mellitus (DM) groups. The arteriosclerosis index, mesangial index, and tube area percentage in the DN group were significantly higher than those in the control and DM groups, but these parameters did not significantly differ between the control and DM groups. The expression of the complement components C1q, mannose-binding lectin (MBL), mannan-binding lectin-associated serine protease (MASP)-2, B factor, C3, and C5b-9 in the DN group was significantly higher than that in the control and DM groups but did not significantly differ between the control and DM groups. Most of the complement components were mainly expressed at the renal tubular site. Correlation analysis showed that 24-h UAE were positively correlated with C1q, MBL, MASP-2, B factor, and C5b-9 expression. MI was positively correlated with MBL, B factor, C3, and C5b-9 expression. AI was positively correlated with C1q, MBL, MASP-2, and B factor expression.Conclusion: Complement components including C1q, MBL, MASP-2, B factor, C3, and C5b-9, were highly expressed in the kidneys of type 2 diabetic rats with DN. Most of the complement components were mainly expressed in the renal tubules. High expression of complement components was found to be associated with the progress of DN. Our study suggests that complement system activation is a progressive factor in type 2 diabetic nephropathy. Inhibition of pathological complement activation may be a promising therapeutic strategy for DN.

Expression of human ficolin-2 in hepatocytes confers resistance to infection by diverse hepatotropic viruses.

The liver-expressed pattern recognition receptors mannose-binding lectin (MBL), ficolin-2 and ficolin-3 contribute to the innate immune response by activating complement. Binding of soluble ficolin-2 to viral pathogens can directly neutralize virus entry. We observed that the human hepatoma cell line HuH7.5, which is routinely used for the study of hepatotropic viruses, is deficient in expression of MBL, ficolin-2 and ficolin-3. We generated a cell line that expressed and secreted ficolin-2. This cell line (HuH7.5 [FCN2]) was more resistant to infection with hepatitis C virus (HCV), ebolavirus and vesicular stomatitis virus, but surprisingly was more susceptible to infection with rabies virus. Cell-to-cell spread of HCV was also inhibited in ficolin-2 expressing cells. This illustrates that ficolin-2 expression in hepatocytes contributes to innate resistance to virus infection, but some viruses might utilize ficolin-2 to facilitate entry.

Decreased nematode clearance and anti-phosphorylcholine-specific IgM responses in mannose-binding lectin-deficient mice.

Brugia malayi is a nematode that causes human lymphatic filariasis. Previously, we showed that mannose-binding lectin (MBL)-A is necessary for clearance of B.malayi microfilariae in mice and presence of MBL-A is linked with maximal levels of parasite-specific IgM. Common human MBL gene polymorphisms result in low MBL expression and lead to recurring bacterial infections. Furthermore, these low-expressing human MBL polymorphisms result in greatly increased susceptibility to lymphatic filarial infection. Indeed, gain of new filarial infections over a 30-year period are 10-fold higher in people with low, compared to high, MBL-expression phenotypes. Human MBL closely resembles mouse MBL-C, rather than MBL-A; therefore, we examined the role of mouse MBL-C in clearance of microfilariae. Absence of MBL-C alone, or both MBL-A and -C, resulted in delayed clearance of microfilariae and reduced parasite-specific IgM in mice. There were few profound changes in B cell sub-populations or in the ability of MBL-deficient mice to respond to T-dependent or T-independent antigens. However, absence of MBL-A and/or MBL-C resulted in reduced IgM to phosphorylcholine, a constituent of filarial and bacterial antigens, suggesting that inability to form proficient antibody responses to this moiety leads to lack of microfilarial clearance and overall susceptibility to filariasis.

Interaction of mannose binding lectin and other pattern recognition receptors in human corneal epithelial cells during Aspergillus fumigatus infection

Mannose binding lectin (MBL), a member of C-type lectin superfamily, plays a significant role in the innate immune system as one of the Pattern-Recognition Receptors (PRRs). This study investigated the relationship between MBL and other PRRs including Dectin-1and TLR2, and detected the reaction of MBL towards the expression of cytokines in human corneal epithelial cells (HCECs) and murine corneas upon Aspergillus fumigatus (A. fumigatus) hyphae infection. We found that MBL was significantly up-regulated in C57BL/6 corneas infected with A. fumigatus and HCECs incubated with A. fumigatus hyphae. Moreover, both of mRNA and protein levels of Dectin-1, TLR2, IL-1β and TNF-α were increased dramatically to peak point with the pretreatment of exogenous MBL, while decreased significantly with the pretreatment of MBL monoclonal antibody in HCECs. Pretreatment with laminarin and TLR2 neutralizing antibody decreased both of mRNA and protein levels of MBL and proinflammatory mediators (IL-1β and TNF-α) in A. fumigatus hyphae infected HCECs. These data demonstrate that A. fumigatus introduce the expression of MBL in human corneas, C57BL/6 corneas and HCECs. MBL, Dectin-1 and TLR2 interact with each other upon the treatment of A. fumigatus, and MBL contributes to the innate immune responses by regulating proinflammatory mediators, such as IL-1β and TNF-α.

Human anti-thrombospondin type 1 domain-containing 7A antibodies induce membranous nephropathy through activation of lectin complement pathway.

To investigate whether the human anti-thrombospondin type 1 domain-containing 7A (THSD7A) antibody-induced membranous nephropathy (MN) is mediated by activating lectin complement pathway. Automatic biochemical apparatus was used to assess renal function of mice. The serum levels of anti-THSD7A antibodies and complement were tested by using ELISA. The expression level of THSD7A and mannose-binding lectin (MBL) in clinical tissue, and the histological features of MN in mice were examined by immunochemical methods. We found that THSD7A, MBL, and complement expression level from patients with circulating anti-THSD7A antibodies were significantly higher than that in normal group. Furthermore, difference of renal function in anti-THSD7A antibody-containing serum treatment groups and control groups was significant. Meanwhile, human anti-THSD7A autoantibodies activated the complement system and induced the histological features of MN in mice. In conclusion, human anti-THSD7A antibodies induce MN through activating MBL lectin complement pathway in mice.

Genetic polymorphisms of C-type lectin receptors in Behcet\u2019s disease in a Chinese Han population

C-type lectin receptors (CLRs) have been demonstrated to be involved in several autoimmune diseases. The role of CLRs in Behcet’s disease (BD) is unknown and thus was the purpose of this study. A two-stage association study was carried out and a total of 766 BD patients and 1674 healthy controls were recruited. Genotyping of 14 SNPs of 13 genes in CLRs was carried out by iPLEX Gold genotyping or polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) assay. The expression of mannose binding lectin 2 (MBL2) and killer cell lectin like receptor C4 (KLRC4) was measured by Real-time PCR. Significantly increased frequencies of the A allele as well as AA genotype of rs1800450 in MBL2 (Pc = 2.50 × 10−6, OR = 1.494; Pc = 2.24 × 10−6,OR = 2.899; respectively) and TT genotype of rs2617170 in KLRC4 (Pc = 2.53 × 10−6, OR = 1.695) and decreased frequencies of GG genotype of rs1800450 (Pc = 1.56 × 10−3, OR = 0.689) and C allele as well as CC genotype of rs2617170 (Pc = 2.05 × 10−9,OR = 0.664; Pc = 1.20 × 10−5, OR = 0.585; respectively) were observed in BD. Two variants, p.Gly54Asp (rs1800450) and p.Asn104Ser (rs2617170) affect MBL2 and KLRC4 protein stability and expression. Our study demonstrates that the MBL2/rs1800450 and KLRC4/rs2617170 are susceptibility factors for BD in a Chinese Han population.

Role of mannose-binding lectin in intestinal homeostasis and fungal elimination.

Mannose-binding lectin (MBL) is a soluble lectin of the innate immune system that is produced by the liver and secreted into the circulation where it activates the lectin complement pathway, enhances phagocytosis of microorganisms by leukocytes, and modulates inflammation. MBL can recognize patterns on the surface of different pathogens, including Candida albicans. Our aims were to investigate whether MBL is expressed in the gut epithelium and to examine its effect on the modulation of intestinal inflammation and C. albicans elimination. Using reverse transcriptase-PCR, MBL transcripts were highly expressed in different parts of the mouse gut. MBL expression was also detected by immunoblotting and immunolocalization in response to C. albicans colonization of the gut; the highest expression of MBL was detected in the stomach. Blocking MBL by administering mannans to mice increased C. albicans colonization. MBL-deficient mice had a higher level of colonization than wild-type mice. Dextran sodium sulfate-induced colitis promoted C. albicans dissemination to the kidneys and lungs of MBL-deficient mice. MBL-deficient mice exhibited elevated expression of interleukin (IL)-17, IL-23, dectin-1, and Toll-like receptor-4. This study shows that MBL expression is induced in the gut in response to C. albicans sensing and is required for intestinal homeostasis and host defense against C. albicans.

High Expression of Mannose-Binding Lectin and the Risk of Vascular Complications of Diabetes: Evidence from a Meta-Analysis.

Vascular inflammation associated with mannose-binding lectin (MBL) may be implicated in the pathogenesis of vascular complications in diabetes. The purpose of this study is to evaluate the association of MBL expression with vascular complications in diabetes. Data from published case-control studies on MBL expression and vascular complications of diabetes were collected up to September 30, 2014. Medline, Embase, and Chinese National Knowledge Infrastructure (CNKI) were searched using the key words "MBL or mannose-binding lectin or mannan-binding lectin," "diabetes or diabetic," and "vascular complication, vascular disease or angiopathy" to identify the articles published in English or Chinese. The combined odds ratio (OR) and 95% confidence interval (CI) for the cumulative rate of vascular complications in the cases of high-expression MBL versus that in cases of low-expression MBL were estimated using a fixed-effects model and a random-effects model. In total, 2,714 cases from 12 articles including 2,256 cases with high-expression MBL (≥ 400 μg/L) and 458 cases with low-expression MBL (< 400 μg/L) were reviewed. The cumulative vascular complication rates were 52.9% (1,194/2,256) in the cases with high expression and 38.4% (176/458) in those with low expression. The combined ORs were 1.6, with a 95% CI ranging from 1.24 to 2.08, in the fixed-effects model and 1.94, with a 95% CI from 1.00 to 3.76, in the random-effects model. High expression of MBL may be correlated with a significantly increased risk of vascular complications in diabetes. Thus MBL detection in diabetes is an effective and feasible method to predict vascular complications.

Early expression of mannose-binding lectin 2 during Aspergillus fumigatus infection in human corneal epithelial cells.

To evaluate the early expression of mannose-binding lectin 2 (MBL2) in human corneal epithelial cells (HCECs) infected by Aspergillus fumigatus (AF). HCECs cultured in vitro with AF antigens and sampled at 0, 0.5, 1, 2, 4, 6 and 8h. The expression of MBL2 mRNA was evaluated by semiquantitative reverse transcription-polymerase chain reaction (RT-PCR). The expression of MBL2 protein in supernatant fluid was shown by enzyme linked immunosorbent assay (ELISA). MBL2 protein in HCECs was detected by immunocytochemistry at 0 and 24h. MBL2 mRNA and protein are expressed in normal HCECs. The expression of MBL2 mRNA and protein in supernatant fluid begin to increase after being stimulated with AF antigens. The most significantly peak of MBL2 mRNA is in 2h. The protein of MBL2 in supernatant fluid decrease gradually after 0.5h. The protein in HCECs expression increase after stimulation of 24h. MBL2 receptor expressed in normal HCECs in vitro. The stimulation by AF antigens can increase the early expression of it.

Expression of mannose-binding lectin in lesions of psoriasis vulgaris

Objective To investigate the expression of mannose-binding lectin (MBL) in lesions of patients with psoriasis vulgaris,and to explore the relationship between MBL and psoriasis pathogenesis.Methods Immunohistochemistry and Western blot were performed to detect the expression of MBL in lesional and normalappearing perilesional skin of 30 patients with progressive psoriasis vulgaris,as well as in normal skin of 30 healthy human controls.Statistical analysis was carried out by t test using SPSS13.0 software.Results Immunohistochemistry showed that MBL was expressed in lesional psoriatic skin,but weakly expressed or absent in normalappearing perilesional skin and normal control skin,with the relative expression level of MBL in lesional skin significantly higher than that in perilesional skin and normal control skin (0.636 7 ± 0.515 1 vs.0.416 3 ± 0.160 1 and 0.381 6 ± 0.310 9,t =2.24,2.32,respectively,both P ＜ 0.05).Western blot revealed a positive expression of MBL protein in all the skin specimens,and the expression intensity of MBL protein in lesional psoriatic skin was significandy increased compared with perilesional psoriatic skin and normal control skin (0.273 1 ± 0.129 4 vs.0.186 3 ± 0.193 1 and 0.149 2 ± 0.268 7,t =2.05,2.28,respectively,both P＜ 0.05).No significant difference was shown in the expression of MBL protein between perilesional psoriatic skin and normal control skin by immunohistochemistry (t =1.51,P ＞ 0.05) or Western blot (t =0.61,P ＞ 0.05).Conclusion There is a high expression of MBL protein in lesions of patients with psoriasis vulgaris,which may be somewhat associated with the pathogenesis of psoriasis. Key words: Psoriasis; Mannose-binding lectins; Immunity, natural

The consequence of low mannose-binding lectin plasma concentration in relation to susceptibility to Salmonella Infantis in chickens

Mannose-binding lectin (MBL) is a key protein in innate immunity. MBL binds to carbohydrates on the surface of pathogens, where it initiates complement activation via the lectin-dependent pathway or facilitates opsonophagocytosis. In vitro studies have shown that human MBL is able to bind to Salmonella, but knowledge in relation to chicken MBL and Salmonella is lacking. In order to study this relation day-old chickens from two selected lines L10H and L10L, differing in MBL serum concentration, were either orally infected with S. Infantis (S.123443) or kept as non-infected controls. The differences between healthy L10H and L10L chicken sublines were more profound than differences caused by the S. Infantis infection. The average daily body weight was higher for L10H than for L10L, regardless of infection, indicating beneficial effects of MBL selection on growth. Salmonella was detected in cloacal swabs and the number of Salmonella positive chickens during the experiment was significantly higher in L10L than L10H, indicating that MBL may affect the magnitude of Salmonella colonisation in day-old chickens. MBL expression was determined in ceca tissue by real-time RT-PCR. L10H chickens showed a significantly higher relative expression than L10L at days 1 and 41 pi, regardless of infection. Finally, flow cytometric analysis of whole blood from infected chickens showed that L10H had a significantly higher count of all assessed leucocyte subsets on day 5 pi, and also a higher count of monocytes on day 12 pi than L10L. No difference was observed between infected and non-infected L10L chicken.

Potential roles of placental human beta-defensin-3 and apolipoprotein B mRNA-editing enzyme catalytic polypeptide 3G in prevention of intrauterine transmission of hepatitis B virus.

Approximately 5% of newborns were infected by hepatitis B virus (HBV) via intrauterine transmission and this is the main reason for high prevalence of HBV in endemic regions. However, the mechanisms by which intrauterine transmission is avoided in most cases remain elusive and placental natural anti-microbial factors may play a role in the prevention of HBV intrauterine transmission. The expression levels of human β-defensin-3 (HBD-3), apolipoprotein B mRNA-editing enzyme catalytic polypeptide 3G (A3G) and mannose binding lectin (MBL) were determined in the placenta of 30 HBV-seronegative pregnant women (controls), 7 HBV-seropositive pregnant women with infants infected via intrauterine transmission (infected group) and 30 HBV-seropositive pregnant women with non-infected infants (non-infected group). The expression of HBD-3, A3G, and MBL of placental trophoblast cell line Swan71 was determined after exposed to HBV. There were significant differences in placental HBD-3 and A3G levels among three groups, but the expression of MBL did not significantly differ. The expressions of HBD-3 and A3G were higher in non-infected group than controls and infected group, but not significantly different between infected group and controls. The exposure to HBV increased significantly the expression of HBD-3, A3G, and MBL by Swan 71. It may be concluded HBV up-regulates HBD-3 and A3G expression in vivo and in vitro in placental trophoblast and lack of this up-regulation is possibly associated with intrauterine transmission of HBV.

Mannose-binding lectin is expressed after clinical and experimental traumatic brain injury and its deletion is protective.

Mannose-binding lectin protein is the activator of the lectin complement pathway. Goals were (1) to investigate mannose-binding lectin expression after human and experimental traumatic brain injury induced by controlled cortical impact and (2) to evaluate whether mannose-binding lectin deletion is associated with reduced sequelae after controlled cortical impact. Translational research, combining a human/experimental observational study and a prospective experimental study. University hospital/research laboratory. Brain-injured patients, C57Bl/6 mice, and mannose-binding lectin-A and mannose-binding lectin-C double-knockout (-/-) mice. Using anti-human mannose-binding lectin antibody, we evaluated mannose-binding lectin expression in tissue samples from six patients who underwent surgery for a cerebral contusion. Immunohistochemistry was also performed on tissues obtained from mice at 30 minutes; 6, 12, 24, 48, and 96 hours; and 1 week after controlled cortical impact using anti-mouse mannose-binding lectin-A and mannose-binding lectin-C antibodies. We evaluated the effects of mannose-binding lectin deletion in wild-type and mannose-binding lectin-A and mannose-binding lectin-C double-knockout mice. Functional outcome was evaluated using the neuroscore and beam walk tests for 4 weeks postinjury (n = 11). Histological injury was evaluated by comparing neuronal cell counts in the cortex adjacent to the contusion (n = 11). Following human traumatic brain injury, we observed mannose-binding lectin-positive immunostaining in the injured cortex as early as few hours and up to 5 days postinjury. Similarly in mice, we observed mannose-binding lectin-C-positive immunoreactivity in the injured cortex beginning 30 minutes and persisting up to 1 week postinjury. The extent of mannose-binding lectin-A expression was lower when compared with that of mannose-binding lectin-C. We observed attenuated sensorimotor deficits in mannose-binding lectin (-/-) mice compared with wild-type mice at 2-4 weeks postinjury. Furthermore, we observed reduced cortical cell loss at 5 weeks postinjury in mannose-binding lectin (-/-) mice compared with wild-type mice. Mannose-binding lectin expression was documented after traumatic brain injury. The reduced sequelae associated with mannose-binding lectin absence suggest that mannose-binding lectin modulation might be a potential target after traumatic brain injury.

Mannose-Binding Lectin (MBL) and MBL-associated serine protease-2 (MASP-2) in women with malignant and benign ovarian tumours.

Mannose-Binding Lectin (MBL) is a serum pattern recognition molecule, able to activate complement in association with MASP proteases. Serum levels of MBL and MASP-2, activities of MBL–MASP complexes, single nucleotide polymorphisms of the MBL2 and MASP2 genes and/or their specific mRNA expression in ovarian sections were investigated in 128 patients suffering from primary ovarian cancer (OC) and compared with 197 controls (C), encompassing both patients with benign ovarian tumours (n = 123) and others with no ovarian pathology (n = 74). MBL deficiency-associated genotypes were more common among OC patients than among controls. The O/O group of genotypes was associated with ovarian cancer (OR 3.5, p = 0.02). In A/A homozygotes, MBL concentrations and activities were elevated in the OC group and correlated with C-reactive protein. Moreover, high MBL serum levels were associated with more advanced disease stage. No differences in distribution of the MASP2 +359 A>G (D120G) SNP or MASP-2 serum levels were found between cancer patients and their controls. However, the highest frequency of the A/G (MASP2) and LXA/O or O/O (MBL2) genotypes was found among OC patients with tumours of G1–2 grade (well/moderately differentiated). Furthermore, MBL deficiency-associated genotypes predicted prolonged survival. None of the parameters investigated correlated with CA125 antigen or patients’ age. The local expression of MBL2 and MASP2 genes was higher in women with ovarian cancer compared with controls. It is concluded that the expression of MBL and MASP-2 is altered in ovarian cancer, possibly indicating involvement of the lectin pathway of complement activation in the disease.Electronic supplementary materialThe online version of this article (doi:10.1007/s00262-014-1579-y) contains supplementary material, which is available to authorized users.