A novel snake venom C-type lectin-like protein modulates blood coagulation by targeting von Willebrand factor and coagulation factor IX.

Snake venom C-type lectin-like proteins (CLPs) belong to the nonenzymatic proteins. To date, no CLP with both platelet and coagulation factors activating activities has been reported. In this study, a novel CLP, termed protocetin, with molecular weight of 29.986 kDa, was purified from the Protobothrops mucrosquamatus venom (PMV). It consists of α- and ß-chains, with 67% similarity in their N-terminal sequence. Protocetin activates glycoprotein Ib (GPIb) by binding to von Willebrand factor (vWF), inducing platelet aggregation. It also activates the intrinsic coagulation pathway by binding to coagulation factor IX. After injection of protocetin into mice at dose of 0.5 µg/g or 1.5 µg/g, it resulted in activation of platelets, a notable reduction in platelet count and prolonged tail bleeding time. Additionally, the plasma activated partial thromboplastin time (APTT) was significantly extended, and the fibrinogen concentration was markedly reduced. Thrombelastogram comfirmed the anticoagulation effect of protocetin. Notably, no microthrombosis was observed in tissues of lung, liver and kidney within 1 h after injection of protocetin into the mice at dose of 0.5 µg/g. This study revealed protocetin as a novel CLP from PMV that has dual functions in activating platelet and coagulation factor IX, thereby modulates coagulation in vivo. This work contributes to a better understanding of the structure and function of snake venom CLP.

Regulation of human GnT-IV family activity by the lectin domain.

N-Glycan branching critically regulates glycoprotein functions and is involved in various diseases. Among the glycosyltransferases involved in N-glycan branching is the human N-acetylglucosaminyltransferase-IV (GnT-IV) family, which has four members: GnT-IVa, GnT-IVb, GnT-IVc, and GnT-IVd. GnT-IVa and GnT-IVb have glycosyltransferase activity that generates the type-2 diabetes-related ß1,4-GlcNAc branch on the α1,3-Man arm of N-glycans, whereas GnT-IVc and GnT-IVd do not. Recently, this enzyme family was found to have a unique lectin domain in the C-terminal region, which is essential for enzyme activity toward glycoprotein substrates but not toward free N-glycans. Furthermore, interaction between the lectin domain of GnT-IV and N-glycan attached to GnT-IV enables self-regulation of GnT-IV activity, indicating that the lectin domain plays a unique and pivotal role in the regulation of GnT-IV activity. In this review, we summarize the GnT-IV family's biological functions, selectivity for glycoprotein substrates, and regulation of enzymatic activity, with a focus on its unique C-terminal lectin domain.

Paired C-type lectin receptors mediate specific recognition of divergent oomycete pathogens in C. elegans.

Innate immune responses can be triggered upon detection of pathogen- or damage-associated molecular patterns by host receptors that are often present on the surface of immune cells. While invertebrates like Caenorhabditis elegans lack professional immune cells, they still mount pathogen-specific responses. However, the identity of host receptors in the nematode remains poorly understood. Here, we show that C-type lectin receptors mediate species-specific recognition of divergent oomycetes in C. elegans. A CLEC-27/CLEC-35 pair is essential for recognition of the oomycete Myzocytiopsis humicola, while a CLEC-26/CLEC-36 pair is required for detection of Haptoglossa zoospora. Both clec pairs are transcriptionally regulated through a shared promoter by the conserved PRD-like homeodomain transcription factor CEH-37/OTX2 and act in sensory neurons and the anterior intestine to trigger a protective immune response in the epidermis. This system enables redundant tissue sensing of oomycete threats through canonical CLEC receptors and host defense via cross-tissue communication.

Evaluation of Jacalin lectin sorbents for the extraction of the human chorionic gonadotropin glycoforms prior to analysis by nano liquid chromatography-high resolution mass spectrometry.

Human chorionic gonadotropin (hCG) is a dimeric, highly glycosylated hormone with a total of 4 N- and 4 O-glycosylation sites in its two subunits, hCGα and hCGß. Recently, we developed a novel nano liquid chromatography coupled to high resolution mass spectrometry (nanoLC-HRMS) method for the analysis and thus the detection of the intact glycoforms of hCG. Here, a sorbent functionalized with the Jacalin lectin was evaluated in solid-phase extraction (SPE) for its potential to fractionate the hCG glycoforms prior to their nanoLC-HRMS analysis at the intact level, which may facilitate the detection of low-abundance glycoforms and may lead to a more detailed characterization of the hormone glycosylation. A commercial sorbent based on Jacalin immobilized on Sepharose and having a lectin density of 4.5 mg per ml of gel was selected to carry out SPE and its capacity was estimated to be of some tens of µg of hCG per ml of lectin sorbent. Next, the SPE protocol was modified to improve the extraction recoveries. Especially, it was noticed that an extensive pre-conditioning procedure prior to the first use of a cartridge was necessary to remove the residual non-grafted lectins. Indeed, if non-grafted lectins are not eliminated, they may bind a part of hCG glycoforms preventing their retention by the sorbent, leading to low extraction recoveries (around 10 %). With the extensive pre-conditioning procedure, the average extraction recoveries for both hCGα and hCGß glycoforms were about 50 %, with either recombinant or urinary hCG. Qualitatively, the fractionation of hCG glycoforms between the washing and elution fractions was achieved with the urinary hCG sample by determining the number of glycoforms detected in each fraction. It appears that 12 hCGα glycoforms have a low affinity (detected only in the washing fraction), 1 a low-medium affinity (detected in washing and elution 1 fractions), 16 a medium affinity (detected in washing, elution 1 and 2 fractions), and 12 a high affinity (detected only in elution 1 and 2 fractions). For the hCGß glycoforms, similarly, 3 have a low affinity and 12 a low-medium affinity. Additionally, the 3 hCGß glycoforms were detected better. A different behavior was observed with the recombinant hCG sample, which indicates glycosylation differences between the two hCG samples. This shows the potential of lectin-based affinity fractionation before nanoLC-HRMS analysis to better characterize the glycosylation state of hCG at the intact level.

Anti-staphylococcal, antibiofilm and trypanocidal activities of CrataBL encapsulated into liposomes: Lectin with potential against infectious diseases.

The present study aimed to evaluate the anti-staphylococcal, antibiofilm, cytotoxicity and trypanocidal activity, mechanisms of parasite death and immunomodulatory effect of CrataBL encapsulated into liposomes (CrataBL-Lipo). CrataBL-Lipo were prepared by the freeze-thaw technique and characterized. Anti-staphylococcal and antibiofilm activities of CrataBL and CrataBL-Lipo were evaluated against standard and clinical strains of Staphylococcus aureus susceptible and resistant. Thus, broth microdilution method was performed to determine the Minimum Inhibitory Concentration (MIC). Antibiofilm activity at subinhibitory concentrations was evaluated using the crystal violet staining method. Cytotoxicity of CrataBL-Lipo was verified in L929 fibroblasts and J774A.1 macrophages by determining the inhibitory concentration necessary to kill 50 % of cells (IC50). Trypanocidal activities of CrataBL-Lipo was evaluated in Trypanosoma cruzi and the efficacy was expressed as the concentration necessary to kill 50 % of parasites (EC50). The mechanisms of parasite death and immunomodulatory effect of CrataBL-Lipo were evaluated using flow cytometry analysis. CrataBL-Lipo presented Ø of 101.9 ± 1.3 nm (PDI = 0.245), ζ of +33.8 ± 1.3 mV and %EE = 80 ± 0.84 %. CrataBL-Lipo presented anti-staphylococcal activity (MIC = 0.56 mg/mL to 0.72 mg/mL). CrataBL-Lipo inhibited 45.4 %-75.6 % of biofilm formation. No cytotoxicity of CrataBL-Lipo was found (IC50 > 100 mg/L). CrataBL-Lipo presented EC50 of 1.1 mg/L, presenting autophagy, apoptosis and necrosis as death profile. In addition, CrataBL-Lipo reduced the production of IL-10 and TNF-α levels, causing an immunomodulatory effect. CrataBL-Lipo has a therapeutic potential for the treatment of staphylococcal infections and Chagas disease exhibiting a high degree of selectivity for the microorganism, and immunomodulatory properties.

Humoral and cellular response to the third COVID-19 vaccination in patients with inborn errors of immunity or mannose-binding lectin deficiency : A prospective controlled open-label trial.

Impaired immune response to COVID-19 (coronavirus disease 2019) vaccination has been reported in patients with inborn errors of immunity (IEI). Repetitive vaccinations are recommended for this vulnerable group. Due to the high diversity within IEI patients, additional safety and immunogenicity data are needed to better understand these aspects especially in less common immunodeficiency syndromes. In this prospective open-label clinical trial, we assessed the humoral immune response and the T­cell response in patients with IEI or severe MBL (mannose-binding lectin) deficiency (IEI/MBLdef) after three vaccinations. A total of 16 patients and 16 matched healthy controls (HC) with suboptimal humoral response defined by anti-SARS-CoV­2 RBD (severe acute respiratory syndrome coronavirus type 2 receptor binding domain) antibodies below 1500 BAU/ml (binding antibody units per ml) after the second COVID-19 vaccination were enrolled in this study and qualified for a third mRNA vaccine dose. After 4 weeks following vaccination, 100% of HC and 75% of IEI/MBLdef patients exhibited anti-SARS-CoV­2 RBD antibodies > 1500 BAU/ml, although the difference was not statistically significant (75% vs. 100%; p = 0.109). Although post-vaccination IEI/MBLdef patients demonstrated significantly increased anti-SARS-CoV­2 RBD antibodies and neutralizing antibodies compared to baseline, these responses were significantly lower in IEI/MBLdef patients compared to HCs. Notably, the third vaccination augmented the cellular immune response to both wild-type and omicron peptide stimulation. No serious adverse events were reported within the 4­week follow-up period and, importantly, vaccination had little to no effect on the long-term disease activity and fatigue. This trial strongly supports the recommendation of repeated COVID-19 vaccinations for patients suffering from immunodeficiencies, especially when they exhibit an initially limited response to the vaccine.

Triton X-100-treated virus-based ELLA demonstrates discordant antigenic evolution of influenza B virus hemagglutinin and neuraminidase.

Neuraminidase (NA)-specific antibodies have been associated with protection against influenza and thus NA is considered a promising target for next-generation vaccines against influenza A (IAV) and B viruses (IBV). NA inhibition (NI) by antibodies is typically assessed using an enzyme-linked lectin assay (ELLA). However, ELLA can be confounded by anti-hemagglutinin (anti-HA) antibodies that block NA by steric hindrance (termed HA interference). Although strategies have been employed to overcome HA interference for IAV, similar approaches have not been assessed for IBV. We found that HA interference is common in ELLA using IBV, rendering the technique unreliable. Anti-HA antibodies were not completely depleted from sera by HA-expressing cell lines, and this approach was of limited utility. In contrast, we find that treatment of virions with Triton X-100, but not Tween-20 or ether, efficiently separates the HA and NA components and overcomes interference caused by anti-HA antibodies. We also characterize a panel of recombinant IBV NA proteins that further validated the results from Triton X-100-treated virus-based ELLA. Using these reagents and assays, we demonstrate discordant antigenic evolution between IBV NA and HA over the last 80 years. This optimized ELLA protocol will facilitate further in-depth serological surveys of IBV immunity as well as antigenic characterization of the IBV NA on a larger scale.IMPORTANCEInfluenza B viruses (IBVs) contribute to annual epidemics and may cause severe disease, especially in children. Consequently, several approaches are being explored to improve vaccine efficacy, including the addition of neuraminidase (NA). Antigen selection and assessment of serological responses will require a reliable serological assay to specifically quantify NA inhibition (NI). Although such assays have been assessed for influenza A viruses (IAVs), this has not been done of influenza B viruses. Our study identifies a readily applicable strategy to measure the inhibitory activity of neuraminidase-specific antibodies against influenza B virus without interference from anti-hemagglutinin (anti-HA) antibodies. This will aid broader serological assessment of influenza B virus-specific antibodies and antigenic characterization of the influenza B virus neuraminidase.

Impact of Lectin biotinylation for surface plasmon resonance and enzyme-linked Lectin assays for protein glycosylation.

Lectins are widely employed for the assessment of protein glycosylation as their carbohydrate binding specificities have been well characterized. In glycosylation assays, lectins are often conjugated with biotin tags, which interact with streptavidin to functionalize biosensing surfaces or recruit signal generating molecules, depending on the assay configuration. We here demonstrate that a high degree of biotin conjugation can limit total capture to streptavidin functionalized SPR surfaces due to multipoint binding, and can additionally bias the reported kinetic evaluations when measuring the interaction between lectins and glycoproteins by SPR. For microplate assays using different configurations, high biotinylation ratios can effectively amplify the signal obtained when using Streptavidin conjugates for detection, in some cases significantly lowering the limit of detection. The cumulative results express the importance of customizing the ligand biotinylation ratios for different assay configurations, as commercially obtained pre-biotinylated lectins are not necessarily optimized for different assay configurations.

The deficient CLEC5A ameliorates the behavioral and pathological deficits via the microglial Aß clearance in Alzheimer's disease mouse model.

BACKGROUND: Alzheimer's disease (AD) is a neurodegenerative disease that causes cognitive dysfunction in older adults. One of the AD pathological factors, ß-Amyloid (Aß), triggers inflammatory responses and phagocytosis of microglia. C-type lectin domain family 5 member A (CLEC5A) induces over-reactive inflammatory responses in several virus infections. Yet, the role of CLEC5A in AD progression remains unknown. This study aimed to elucidate the contribution of CLEC5A to Aß-induced microglial activation and behavioral deficits. METHODS: The AD mouse model was crossed with Clec5a knockout mice for subsequent behavioral and pathological tests. The memory deficit was revealed by the Morris water maze, while the nociception abnormalities were examined by the von Frey filament and hotplate test. The Aß deposition and microglia recruitment were identified by ELISA and immunohistochemistry. The inflammatory signals were identified by ELISA and western blotting. In the Clec5a knockdown microglial cell model and Clec5a knockout primary microglia, the microglial phagocytosis was revealed using the fluorescent-labeled Aß. RESULTS: The AD mice with Clec5a knockout improved Aß-induced memory deficit and abnormal nociception. These mice have reduced Aß deposition and increased microglia coverage surrounding the amyloid plaque, suggesting the involvement of CLEC5A in AD progression and Aß clearance. Moreover, the phagocytosis was also increased in the Aß-stressed Clec5a knockdown microglial cell lines and Clec5a knockout primary microglia. CONCLUSION: The Clec5a knockout ameliorates AD-like deficits by modulating microglial Aß clearance. This study implies that targeting microglial Clec5a could offer a promising approach to mitigate AD progression.

Purification and partial characterization of a new melibiose-specific lectin from Bauhinia catingae Harms.

Lectins are ubiquitous proteins that selectively bind to carbohydrates, serving as vital models for understanding protein-carbohydrate interactions. While extensively distributed across various life forms, plant lectins, especially from the Leguminosae family, have garnered significant attention. However, limited research exists on lectins from the Caesalpinioideae subfamily, suggesting a source of untapped biotechnological potential. This underscores the imperative for further exploration, particularly in isolating lectins from the Bauhinia genus, which remains relatively understudied, despite harboring lectins with diverse characteristics and promising biotechnological activities. In this study, a novel lectin extracted from Bauhinia catingae Harms seeds (BCL) was isolated in three chromatographic steps. BCL exhibited affinity for galactose and derivatives, akin to other Bauhinia lectins, with SDS-PAGE confirming its molecular weight around 30 kDa. Notably, BCL demonstrated stability across temperature and pH ranges and lacked metalloprotein characteristics. Electrospray ionization mass spectrometry revealed a partial sequence covering 81 % of the total protein sequence with nearly 80 % identity to Bauhinia forficata. Structural analysis suggested a ß-sheet-rich secondary structure similar to that of other lectins. Further structural elucidation of BCL is essential to unveil its full potential and applications.

BLNK negatively regulates innate antifungal immunity through inhibiting c-Cbl-mediated macrophage migration.

B cell linker protein (BLNK) is crucial for orchestrating B cell receptor-associated spleen tyrosine kinase (Syk) signaling. However, the role of BLNK in Syk-coupled C-type lectin receptor (CLR) signaling in macrophages remains unclear. Here, we delineate that CLRs govern the Syk-mediated activation of BLNK, thereby impeding macrophage migration by disrupting podosome ring formation upon stimulation with fungal ß-glucans or α-mannans. Mechanistically, BLNK instigates its association with casitas B-lineage lymphoma (c-Cbl), competitively impeding the interaction between c-Cbl and Src-family kinase Fyn. This interference disrupts Fyn-mediated phosphorylation of c-Cbl and subsequent c-Cbl-associated F-actin assembly. Consequently, BLNK deficiency intensifies CLR-mediated recruitment of the c-Cbl/phosphatidylinositol 3-kinase complex to the F-actin cytoskeleton, thereby enhancing macrophage migration. Notably, mice with monocyte-specific BLNK deficiency exhibit heightened resistance to infection with Candida albicans, a prominent human fungal pathogen. This resistance is attributed to the increased infiltration of Ly6C+ macrophages into renal tissue. These findings unveil a previously unrecognized role of BLNK for the negative regulation of macrophage migration through inhibiting CLR-mediated podosome ring formation during fungal infections.

Identification of Podoplanin Aptamers by SELEX for Protein Detection and Inhibition of Platelet Aggregation Stimulated by C-Type Lectin-like Receptor 2.

Tumor cell-induced platelet aggregation (TCIPA) is a mechanism for the protection of tumor cells in the bloodstream and the promotion of tumor progression and metastases. The platelet C-type lectin-like receptor 2 (CLEC-2) can bind podoplanin (PDPN) on a cancer cell surface to facilitate TCIPA. Selective blockage of PDPN-mediated platelet-tumor cell interaction is a plausible strategy for inhibiting metastases. In this study, we aimed to screen for aptamers, which are the single-stranded DNA oligonucleotides that form a specific three-dimensional structure, bind to specific molecular targets with high affinity and specificity, bind to PDPN, and interfere with PDPN/CLEC-2 interactions. The systematic evolution of ligands by exponential enrichment (SELEX) was employed to enrich aptamers that recognize PDPN. The initial characterization of ssDNA pools enriched by SELEX revealed a PDPN aptamer designated as A1 displaying parallel-type G-quadruplexes and long stem-and-loop structures and binding PDPN with a material with a dissociation constant (Kd) of 1.3 ± 1.2 nM. The A1 aptamer recognized both the native and denatured form of PDPN. Notably, the A1 aptamer was able to quantitatively detect PDPN proteins in Western blot analysis. The A1 aptamer could interfere with the interaction between PDPN and CLEC-2 and inhibit PDPN-induced platelet aggregation in a concentration-dependent manner. These findings indicated that the A1 aptamer is a candidate for the development of biosensors in detecting the levels of PDPN expression. The action by A1 aptamer could result in the prevention of tumor cell metastases, and if so, could become an effective pharmacological agent in treating cancer patients.

Characterization and Expression Analysis of the C-Type Lectin Ladderlectin in Litopenaeus vannamei Post-WSSV Infection.

C-type lectins are known for agglutination activity and play crucial roles in regulating the prophenoloxidase (proPO) activation system, enhancing phagocytosis and encapsulation, synthesizing antimicrobial peptides, and mediating antiviral immune responses. This work cloned a C-type lectin, ladderlectin (LvLL), from Litopenaeus vannamei. LvLL comprised a 531 bp open reading frame (ORF) that encoded 176 amino acids. The predicted LvLL protein included a signal peptide and a CLECT domain. LvLL was predicted to feature a transmembrane region, suggesting it may be a transmembrane protein. LvLL was predominantly expressed in the shrimp's hepatopancreas. After WSSV infection, LvLL expression in the hepatopancreas increased significantly by 11.35-fold after 228 h, indicating a general upregulation. Knockdown of LvLL resulted in a significant decrease in WSSV viral load and a notable increase in shrimp survival rates. Additionally, knockdown of LvLL led to a significant downregulation of apoptosis-related genes Bcl-2 and caspase 8 and a significant upregulation of p53 and proPO in WSSV-infected shrimp. This study showed that LvLL played a vital role in the interaction between L. vannamei and WSSV.

The liquid lectin array detects compositional glycocalyx differences using multivalent DNA-encoded lectins on phage.

Selective detection of disease-associated changes in the glycocalyx is an emerging field in modern targeted therapies. Detecting minor glycan changes on the cell surface is a challenge exacerbated by the lack of correspondence between cellular DNA/RNA and glycan structures. We demonstrate that multivalent displays of lectins on DNA-barcoded phages-liquid lectin array (LiLA)-detect subtle differences in density of glycans on cells. LiLA constructs displaying 73 copies of diCBM40 (CBM) lectin per virion (φ-CBM73) exhibit non-linear ON/OFF-like recognition of sialoglycans on the surface of normal and cancer cells. A high-valency φ-CBM290 display, or soluble CBM protein, cannot amplify the subtle differences detected by φ-CBM73. Similarly, multivalent displays of CBM and Siglec-7 detect differences in the glycocalyx between stem-like and non-stem populations in cancer. Multivalent display of lectins offer in situ detection of minor differences in glycocalyx in cells both in vitro and in vivo not feasible to currently available technologies.

Mannose and Lactobionic Acid in Nasal Vaccination: Enhancing Antigen Delivery via C-Type Lectin Receptors.

BACKGROUND/OBJECTIVES: Nasal vaccines are a promising strategy for enhancing mucosal immune responses and preventing diseases at mucosal sites by stimulating the secretion of secretory IgA, which is crucial for early pathogen neutralization. However, designing effective nasal vaccines is challenging due to the complex immunological mechanisms in the nasal mucosa, which must balance protection and tolerance against constant exposure to inhaled pathogens. The nasal route also presents unique formulation and delivery hurdles, such as the mucous layer hindering antigen penetration and immune cell access. METHODS: This review focuses on cutting-edge approaches to enhance nasal vaccine delivery, particularly those targeting C-type lectin receptors (CLRs) like the mannose receptor and macrophage galactose-type lectin (MGL) receptor. It elucidates the roles of these receptors in antigen recognition and uptake by antigen-presenting cells (APCs), providing insights into optimizing vaccine delivery. RESULTS: While a comprehensive examination of targeted glycoconjugate vaccine development is outside the scope of this study, we provide key examples of glycan-based ligands, such as lactobionic acid and mannose, which can selectively target CLRs in the nasal mucosa. CONCLUSIONS: With the rise of new viral infections, this review aims to facilitate the design of innovative vaccines and equip researchers, clinicians, and vaccine developers with the knowledge to enhance immune defenses against respiratory pathogens, ultimately protecting public health.

Concanavalin a Grafted Nanoemulsions for Nasal Delivery: Preliminary Studies with Fluorescently Labelled Formulations.

Nasal delivery is a non-invasive strategy for effective drug delivery. Nevertheless, in order to promote drug uptake by the nasal mucosa, it is fundamental to increase its residence time in the administration site. To this aim, nano-sized drug delivery systems are widely exploited. Within this context, the commercially available nanoemulsion for parenteral nutrition is a biocompatible, safe and clinically approved vehicle for drug delivery. Furthermore, the nanodroplet surface can be modified via a well-established protocol to graft Concavalin A, a lectin capable of improving the mucosal adhesion, by binding to the α-mannose and α-glucose residues of the mucosal glycocalyx. The obtained targeted formulation is able to induce haemagglutination, as opposite to non-modified nanoemulsion. Furthermore, the ConA grafting maintains the physicochemical properties of the nanodroplets (size~230 nm, Z < -35 mV) and does not interfere with the loading of the Rose Bengal fluorescent probe. Fluorescently labelled ConA grafted nanodroplets showed enhanced permeation and accumulation in ex vivo bovine nasal mucosa. This study is a proof of concept that Concanavalin A can be used to decorate the surface of nanodroplets, acting as a permeation promoter.

Identification of a Novel Antiviral Lectin against SARS-CoV-2 Omicron Variant from Shiitake-Mushroom-Derived Vesicle-like Nanoparticles.

Lectins are a class of carbohydrate-binding proteins that may have antiviral activity by binding to the glycans on the virion surface to interfere with viral entry. We have identified a novel lectin (named Shictin) from Shiitake mushroom (Lentinula edodes)-derived vesicle-like nanoparticles (VLNs, or exosomes) that exhibits strong activity against the SARS-CoV-2 Omicron variant with an IC50 value of 87 nM. Shictin contains 298 amino acids and consists of two unique domains (N-terminal and C-terminal domain). The N-terminal domain is the carbohydrate-binding domain (CBD) that is homologous with CBDs of other lectins, suggesting that Shictin inhibits SARS-CoV-2 infection by binding to the glycans on the virion surface to prevent viral entry. This finding demonstrates that exosomes of vegetables are a valuable source for the identification of antiviral lectins. Therefore, it is believed that lectins from vegetable VLNs have potential as antiviral therapeutic agents.

Clinical associations of complement-activating collectins, collectin-10, collectin-11 and mannose-binding lectin in preterm neonates.

Introduction: Premature and low-birthweight infants are at especially high risk of perinatal complications, including impaired thermoregulation, infections and respiratory distress. Such adverse effects and the need for invasive procedures are associated with high mortality among preterms. This study focused on the influence of the innate immune system and tested the levels of collectins, collectin-10 (CL-10), collectin-11 (CL-11) and mannose-binding lectin (MBL) in preterm neonates. Methods: Cord blood was collected from 535 preterms (born at gestational age ≤37 weeks). COLEC10 and COLEC11 polymorphisms were analyzed by real-time PCR and those of MBL2 by PCR/PCR-RFLP. The concentrations of collectins in sera from cord blood were determined with ELISA. Findings: Low concentrations of CL-10 in cord sera (<462 ng/ml corresponding to the 10th percentile) were significantly associated with births at GA ≤32 weeks. Median levels of both CL-10 and CL-11 were significantly lower in preterms with very low birthweight (<1500 g), low Apgar 1' score and those who needed prolonged hospitalisation. Lower median CL-10 was also observed in fetal growth restriction cases. An important finding was the decreased concentrations of CL-10, CL-11 and MBL in respiratory distress syndrome (RDS). For CL-10 and CL-11, that relationship was confined to infants born at GA ≥33 weeks and/or with body mass at birth ≥1500 g. Only CL-10 was found to influence susceptibility to early-onset infections. COLEC11 heterozygosity for the activity-decreasing polymorphism (rs7567833, +39618 A>G, His219Arg) was more common in preterm premature rupture of membranes (pPROM) cases, compared with corresponding reference groups. Furthermore, C/T or T/T genotypes at COLEC11 at rs3820897 (-9570 C>T) as well as MBL deficiency-associated MBL2 gene variants were more common in preterms diagnosed with RDS than among unaffected newborns. Conclusion: The complement-activating collectins investigated here could be important for maintaining homeostasis in preterm neonates. Despite similar structure and specificity, MBL, CL-10 and CL-11 manifest a different spectrum of clinical associations.

Role of various virulence factors involved in the pathogenesis of Entamoeba histolytica.

Developing countries continuously face challenges to get rid of amoebiasis, a protozoan disease caused by Entamoeba histolytica. Every year around 900 million people get affected by amoebiasis, among them only 10 % of people show the symptoms of the disease while 90 % of people do not show any symptoms but still, serve as carriers of the disease. Asymptomatic persons carry cysts of Entamoeba in their fecal matter, which is carried by house flies to contaminate the food and water. Entamoeba histolytica is a very successful pathogen because it has very well-developed virulence factors that function in infection to host as well as in overcoming the host's immune response. However, researchers have very little information about the clear relationship between virulence factors and the virulence of Entamoeba histolytica, through various research, researchers have been able to identify key pathogenic factors that are crucial to the pathogenesis of amoebiasis and have provided valuable insights into the development of the disease. The objective of this review is to underscore various virulence factors (Monosaccharides, Gal/GalNAc lectin, extracellular vesicles, cysteine proteases, amoeba-pores, and actin microfilament) involved in pathogenesis which may be helpful for designing of future drug or therapy.

Detection of Tn-antigen in breast and prostate cancer models by VVL-labeled red dye-doped nanoparticles.

Aim: Fluorescence detection of breast and prostate cancer cells expressing Tn-antigen, a tumor marker, with Vicia villosa lectin (VVL)-labeled nanoparticles.Materials & methods: Breast and prostate cancer cells engineered to express high levels of Tn-antigen and non-engineered controls were incubated with VVL-labeled or unlabeled red dye-doped silica-coated polystyrene nanoparticles. The binding to cells was studied with flow cytometry, confocal microscopy, and electron microscopy.Results: Flow cytometry showed that the binding of VVL-labeled nanoparticles was significantly higher to Tn-antigen-expressing cancer cells than controls. Confocal microscopy demonstrated that particles bound to the cell surface. According to the correlative light and electron microscopy the particles bound mostly as aggregates.Conclusion: VVL-labeled nanoparticles could provide a new tool for the detection of Tn-antigen-expressing breast and prostate cancer cells.

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