Search

Compared to the general population, patients with inflammatory bowel disease (IBD) are less likely to be vaccinated, putting them at an increased risk of vaccine-preventable illnesses. This risk is further compounded by the immunosuppressive therapies commonly used in IBD management. Therefore, developing new treatments for IBD that maintain immune function is crucial, as successful management can lead to better vaccination outcomes and overall health for these patients. Here, we investigate the potential of recombinant banana lectin (rBanLec) as a supporting therapeutic measure to improve IBD control and possibly increase vaccination rates among IBD patients. By examining the therapeutic efficacy of rBanLec in a murine model of experimental colitis, we aim to lay the foundation for its application in improving vaccination outcomes. After inducing experimental colitis in C57BL/6 and BALB/c mice with 2,4,6-trinitrobenzene sulfonic acid, we treated animals orally with varying doses of rBanLec 0.1–10 µg/mL (0.01—1 µg/dose) during the course of the disease. We assessed the severity of colitis and rBanLec's modulation of the immune response compared to control groups. rBanLec administration resulted in an inverse dose–response reduction in colitis severity (less pronounced weight loss, less shortening of the colon) and an improved recovery profile, highlighting its therapeutic potential. Notably, rBanLec-treated mice exhibited significant modulation of the immune response, favoring anti-inflammatory pathways (primarily reduction in a local [TNFα]/[IL-10]) crucial for effective vaccination. Our findings suggest that rBanLec could mitigate the adverse effects of immunosuppressive therapy on vaccine responsiveness in IBD patients. By improving the underlying immune response, rBanLec may increase the efficacy of vaccinations, offering a dual benefit of disease management and prevention of vaccine-preventable illnesses. Further studies are required to translate these findings into clinical practice. [ABSTRACT FROM AUTHOR]

Background The ongoing concern surrounding coronavirus disease 2019 (COVID-19) primarily stems from continuous mutations in the genome of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), leading to the emergence of numerous variants. The receptor-binding domain (RBD) in the S1 subunit of the S protein of the virus plays a crucial role in recognizing the host's angiotensin-converting enzyme 2 (hACE2) receptor and facilitating cell membrane fusion processes, making it a potential target for preventing viral entrance into cells. This research aimed to determine the potential of banana lectin (BanLec) proteins to inhibit SARS-CoV-2 attachment to host cells by inter-acting with RBD through computational modeling. Materials and methods The BanLecs were selected through a sequence analysis process. Subsequently, the genes encoding BanLec proteins were retrieved from the Banana Genome Hub database. The FGENESH online tool was then employed to predict protein sequences, while web-based tools were utilized to assess the physicochemical properties, allergenicity, and toxicity of BanLecs. The RBDs of SARS-CoV-2 were modeled using the SWISS-MODEL in the following step. Molecular docking procedures were conducted with the aid of ClusPro 2.0 and HDOCK web servers. The three-dimensional structures of the docked complexes were visualized using PyMOL. Finally, molecular dynamics simulations were performed to investigate and validate the interactions of the complexes exhibiting the highest interactions, facilitating the simulation of their dynamic properties. Results The BanLec proteins were successfully modeled based on the RNA sequences from two species of banana (Musa sp.). Moreover, an amino acid modification in the BanLec protein was made to reduce its mitogenicity. Theoretical allergenicity and toxicity predictions were conducted on the BanLecs, which suggested they were likely non-allergenic and contained no discernible toxic domains. Molecular docking analysis demonstrated that both altered and wild-type BanLecs exhibited strong affinity with the RBD of different SARS-CoV-2 variants. Further analysis of the molecular docking results showed that the BanLec proteins interacted with the active site of RBD, particularly the key amino acids residues responsible for RBD's binding to hACE2. Molecular dynamics simulation indicated a stable inter-action between the Omicron RBD and BanLec, maintaining a root-mean-square deviation (RMSD) of approximately 0.2 nm for a duration of up to 100 ns. The individual proteins also had stable structural conformations, and the complex demonstrated a favorable binding-free energy (BFE) value. Conclusions These results confrm that the BanLec protein is a promising candidate for developing a potential therapeutic agent for combating COVID-19. Furthermore, the results suggest the possibility of BanLec as a broad-spectrum antiviral agent and highlight the need for further studies to examine the protein's safety and effectiveness as a potent antiviral agent. [ABSTRACT FROM AUTHOR]

Methicillin resistant Staphylococcus aureus (MRSA) is an emerging pathogen posing a considerable burden on the healthcare system due to its involvement in skin and soft tissue infections (SSTIs). Lectins are carbohydrate binding proteins found ubiquitously in animals, plants and microorganisms. Extraction and isolation of proteins from Musa acuminata were performed by using Affinity chromatography with Sephadex G 75 to determine antibiofilm activity against MRSA. Enterococcus strains obtained from dairy products, beans and vegetables were also screened for its potential to inhibit growth and biofilm formation of MRSA by using 96 well microtiter plates. Synergistic effect of cell free supernatant of Enterococcus with proteins from ripe banana were also tested. BanLec was successfully isolated and appeared as 15 KDa band after SDS-PAGE (15%) while multiple bands of unbound protein fractions were observed. The unbound fractions showed inhibition of planktonic cells and biofilm but BanLec exhibited no significant effect. The CFS of Enterococcus faecium (LCM002), Enterococcus lactis (LCM003) and Enterococcus durans (LCM004 and LCM005) displayed antagonistic effects against pathogen. The synergistic effect of CFS from E. lactis (LCM003) and unbound proteins showed inhibition of biofilm and pathogenic growth. This study demonstrates the use of Enterococcus species and plant proteins against pathogens and results suggested that it can inhibit the growth of resistant strains of Staphylococcus aureus and their synergistic effect has opened new ways to tackle emerging resistance. Furthermore, after assessment of Enterococcus as probiotics, this could be used in food industries as well as in treatment of severe skin infections. [ABSTRACT FROM AUTHOR]

The aim of the study was to gain deeper insights in the potential of polyclonal stimulation of PBMC with banana lectin (BanLec) from Musa paradisiaca. BanLec induced a marked proliferative response in cow and pig PBMC, but was strongest in pigs, where it induced an even higher proliferation rate than Concanavalin A. Molecular processes associated with respective responses in porcine PBMC were examined with differential proteome analyses. Discovery proteomic experiments was applied to BanLec stimulated PBMC and cellular and secretome responses were analyzed with label free LC-MS/MS. In PBMC, 3955 proteins were identified. After polyclonal stimulation with BanLec, 459 proteins showed significantly changed abundance in PBMC. In respective PBMC secretomes, 2867 proteins were identified with 231 differentially expressed candidates as reaction to BanLec stimulation. The transcription factor “E74 like ETS transcription factor 1 (ELF1)” was solely enriched in BanLec stimulated PBMC. BanLec induced secretion of several immune regulators, amongst them positive regulators of activated T cell proliferation and Jak-STAT signaling pathway. Top changed immune proteins were CD226, CD27, IFNG, IL18, IL2, CXCL10, LAT, ICOS, IL2RA, LAG3, and CD300C. BanLec stimulates PBMC of cows and pigs polyclonally and induces IL2 pathway and further proinflammatory cytokines. Proteomics data are available via ProteomeXchange with identifier PXD027505.

H84T-Banana Lectin (BanLec) CAR-NK cells bind high mannose glycosites that decorate the SARS-CoV-2 envelope, thereby decreasing cellular infection in a model of SARS-CoV-2. H84T-BanLec CAR-NK cells are innate effector cells, activated by virus. This novel cellular agent is a promising therapeutic, capable of clearing circulating SARS-CoV-2 virus and infected cells. Banana Lectin (BanLec) binds high mannose glycans on viral envelopes, exerting an anti-viral effect. A point mutation (H84T) divorces BanLec mitogenicity from antiviral activity. SARS-CoV-2 contains high mannose glycosites in proximity to the receptor binding domain of the envelope Spike (S) protein. We designed a chimeric antigen receptor (CAR) that incorporates H84T-BanLec as the extracellular moiety. Our H84T-BanLec CAR was devised to specifically direct NK cell binding of SARS-CoV-2 envelope glycosites to promote viral clearance. The H84T-BanLec CAR was stably expressed at high density on primary human NK cells during two weeks of ex vivo expansion. H84T-BanLec CAR-NK cells reduced S-protein pseudotyped lentiviral infection of 293T cells expressing ACE2, the receptor for SARS-CoV-2. NK cells were activated to secrete inflammatory cytokines when in culture with virally infected cells. H84T-BanLec CAR-NK cells are a promising cell therapy for further testing against wild-type SARS-CoV-2 virus in models of SARS-CoV-2 infection. They may represent a viable off-the-shelf immunotherapy for patients suffering from COVID-19. [ABSTRACT FROM AUTHOR]

H84T-Banana Lectin (BanLec) CAR-NK cells bind high mannose glycosites that decorate the SARS-CoV-2 envelope, thereby decreasing cellular infection in a model of SARS-CoV-2. H84T-BanLec CAR-NK cells are innate effector cells, activated by virus. This novel cellular agent is a promising therapeutic, capable of clearing circulating SARS-CoV-2 virus and infected cells. Banana Lectin (BanLec) binds high mannose glycans on viral envelopes, exerting an anti-viral effect. A point mutation (H84T) divorces BanLec mitogenicity from antiviral activity. SARS-CoV-2 contains high mannose glycosites in proximity to the receptor binding domain of the envelope Spike (S) protein. We designed a chimeric antigen receptor (CAR) that incorporates H84T-BanLec as the extracellular moiety. Our H84T-BanLec CAR was devised to specifically direct NK cell binding of SARS-CoV-2 envelope glycosites to promote viral clearance. The H84T-BanLec CAR was stably expressed at high density on primary human NK cells during two weeks of ex vivo expansion. H84T-BanLec CAR-NK cells reduced S-protein pseudotyped lentiviral infection of 293T cells expressing ACE2, the receptor for SARS-CoV-2. NK cells were activated to secrete inflammatory cytokines when in culture with virally infected cells. H84T-BanLec CAR-NK cells are a promising cell therapy for further testing against wild-type SARS-CoV-2 virus in models of SARS-CoV-2 infection. They may represent a viable off-the-shelf immunotherapy for patients suffering from COVID-19.

• The molecular modeling and design of the Bet v1-BanLec construct was done in silico. • IgE reactive epitopes of the Bet v 1 were preserved in Bet v 1-BanLec. • Bet v 1-BanLec retained specific mannose-binding capacity. • Bet v 1-BanLec promote IL-10 production in peritoneal murine macrophages. Allergen-specific immunotherapy (AIT) is a desensitizing treatment for allergic diseases that corrects the underlined pathological immune response to innocuous protein antigens, called allergens. Recombinant allergens employed in the AIT allowed the production of well-defined formulations that possessed consistent quality but were often less efficient than natural allergen extracts. Combining recombinant allergens with an adjuvant or immunomodulatory agent could improve AIT efficacy. This study aimed to perform structural and functional characterization of newly designed recombinant chimera composed of the Bet v 1, the major birch pollen allergen, and Banana Lectin (BanLec), TLR2, and CD14 binding protein, for the application in AIT. rBet v 1-BanLec chimera was designed in silico and expressed as a soluble fraction in Escherichia coli. Purified rBet v 1-BanLec (33.4 kDa) retained BanLec-associated biological activity of carbohydrate-binding and preserved IgE reactive epitopes of Bet v 1. The chimera revealed secondary structures with predominant β sheets. The immunomodulatory capacity of rBet v 1-BanLec tested on macrophages showed changes in myeloperoxidase activity, reduced NO production, and significant alterations in the production of cytokines when compared to both rBanLec and rBet v 1. Comparing to rBet v 1, rBet v 1-BanLec was demonstrated to be more efficient promoter of IL-10 production as well as weaker inducer of NO production and secretion of pro-inflammatory cytokines TNFα, and IL-6. The ability of rBet v 1-BanLec to promote IL-10 in together with the preserved 3D structure of Bet v 1 part implies that the construct might exert a beneficial effect in the allergen-specific immunotherapy. [ABSTRACT FROM AUTHOR]

Bovine viral diarrhea virus (BVDV) and bovine alphaherpesvirus type 1 (BoHV-1) are responsible for major economic losses of livestock worldwide, making their eradication an important objective of veterinary research. Vaccines against these infectious agents are commercially available but have some limitations due to the specific features of these viral agents. The development of new antiviral drugs is therefore essential. Native banana lectin (BanLec) is a lectin isolated from banana fruit (Musa acuminata) and has a high affinity for mannose glycans found in several viral envelopes. The inhibitory properties of this lectin against several viruses has already been demonstrated. The aim of this work was therefore to test the antiviral and virucidal activities of BanLec against BVDV-1 and BoHV-1. Its antiviral activity was assessed by measuring the viral titer and viability of susceptible Madin-Darby Bovine Kidney cells (MDBK) treated with BanLec before and after viral infection. The virucidal properties of BanLec were determined by preincubation of the lectin with the viruses, followed by measurement of the viral load in exposed cells. Treatment with 25 μg/mL BanLec resulted in high levels of inhibition against BVDV-1 (99.98%) and BoHV-1 (99.68%) without affecting cell viability, demonstrating promising potential as an antiviral agent. • Purified banana lectin (BanLec) has antiviral activity against Bovine Viral Diarrhea Virus 1 and Bovine Alphaherpesvirus 1. • BanLec inhibited viral entry and replication in culture bovine cells. • Significant decreases in viral titres were observed without significant cellular toxicity. • Antiviral activity could be explained due to the bind of carbohydrates moieties on cellular and viral surface. [ABSTRACT FROM AUTHOR]

[Display omitted] • rBet v 1a-BanLec wt induce upregulation of IL-10 gene expression in Caco-2/THP-1 co-culture. • rBet v 1a-BanLec wt induce upregulation of IFNγ gene expression in Caco-2/THP-1 co-culture. • rBet v 1a-BanLec wt induced secretion of IL-10 in PBMCs of birch pollen allergic donors. Novel allergen immunotherapy (AIT) approaches necessitate the use of more effective and safe therapeutics, which can be accomplished by employing novel adjuvants for improved innate immune cell activation, as well as hypoallergenic allergen forms. In this study, we investigate the immunomodulatory effects of a chimera rBet v 1a-BanLec wt (rBv1a-BL wt ; C wt) composed of the major birch pollen allergen Bet v 1a and banana lectin (BanLec wt ; BLwt) and two novel chimeras, rBv1l-BL H84T (rBet v 1l-BanLec H84T ; C1) and rBL H84T -Bv1l (rBanLec H84T -Bet v 1l; C2), both composed of BL H84T and hypoallergenic birch pollen allergen Bv1l in the co-culture model Caco-2/THP-1, and PBMCs from donors with birch pollen allergy. The chimeric molecules rBv1l-BL H84T (C1) and rBL H84T -Bv1l (C2) were created in silico and then produced in E. coli using recombinant DNA technology. Real-time PCR analysis of gene expression following compound treatment in the co-culture model revealed that all three chimeras have the potential to induce the anti-inflammatory cytokine IL-10 gene expression in Caco-2 cells and IFN-γ gene expression in THP-1 cells. Sandwich ELISA revealed that Cwt increased IL-10 secretion and IFN-/IL-4 levels in PBMCs from birch pollen allergic donors, whereas C1 and C2 were less effective. The findings suggest that Cwt should be analyzed further due to its potential benefit in AIT. [ABSTRACT FROM AUTHOR]

The surface of microorganisms is covered with polysaccharide structures which are in immediate contact with receptor structures on host's cells and antibodies. The interaction between microorganisms and their host is dependent on surface glycosylation and in this study we have tested the interaction of plant lectins with different microorganisms. Enzyme-linked lectin sorbent assay - ELLSA was used to test the binding of recombinant Musa acuminata lectin - BL to 27 selected microorganisms and 7 other lectins were used for comparison: Soy bean agglutinin - SBA, Lens culinaris lectin - LCA, Wheat germ agglutinin - WGA, RCA120 - Ricinus communis agglutinin, Con A - from Canavalia ensiformis, Sambucus nigra agglutinin - SNA I and Maackia amurensis agglutinin - MAA. The goal was to define the microorganisms' surface glycosylation by means of interaction with the selected plant lectins and to make a comparison with BL. Among the tested lectins most selective binding was observed for RCA120 which preferentially bound Lactobacillus casei DG. Recombinant banana lectin showed specific binding to all of the tested fungal species. The binding of BL to Candida albicans was further tested with fluorescence microscopy and flow cytometry and it was concluded that this lectin can differentiate ß-glucan rich surfaces. The binding of BL to S. boulardii could be inhibited with ß-glucan from yeast with IC50 1.81 μg mL−1 and to P. roqueforti with 1.10 μg mL−1. This unique specificity of BL could be exploited for screening purposes and potentially for the detection of ß-glucan in solutions. [ABSTRACT FROM AUTHOR]

Fluorescently labeled lectins are useful tools for in vivo and in vitro studies of the structure and function of tissues and various pathogens such as viruses, bacteria, and fungi. For the evaluation of high-mannose glycans present on various glycoproteins, a three-dimensional (3D) model of the chimera was designed from the crystal structures of recombinant banana lectin (BanLec, Protein Data Bank entry (PDB): 5EXG) and an enhanced green fluorescent protein (eGFP, PDB 4EUL) by applying molecular modeling and molecular mechanics and expressed in Escherichia coli. BanLec-eGFP, produced as a soluble cytosolic protein of about 42 kDa, revealed β-sheets (41%) as the predominant secondary structures, with the emission peak maximum detected at 509 nm (excitation wavelength 488 nm). More than 65% of the primary structure was confirmed by mass spectrometry. Competitive BanLec-eGFP binding to high mannose glycans of the influenza vaccine (Vaxigrip®) was shown in a fluorescence-linked lectin sorbent assay (FLLSA) with monosaccharides (mannose and glucose) and wild type BanLec and H84T BanLec mutant. BanLec-eGFP exhibited binding to mannose residues on different strains of Salmonella in flow cytometry, with especially pronounced binding to a Salmonella Typhi clinical isolate. BanLec-eGFP can be a useful tool for screening high-mannose glycosylation sites on different microorganisms.

Recombinant banana lectin isoform (rBanLec) attaches specifically to the mucosal surface, crosses the epithelial barrier and then directly affects the immune response in mouse colon. Structural characteristics, specificity and physiological impacts of rBanLec reported until now highly resemble those of its natural counterpart. Here, we demonstrated that a dose-dependent stimulation of the colon with rBanLec skewed the immune response towards Th1/Th17 direction and this effect was counterbalanced by the rise in IL-10 production. Qualitative and quantitative characteristics of the established cytokine network were dependent on the applied rBanLec concentration. In addition, rBanLec enhanced local NO production and myeloperoxidase activity and promoted an increase in local IgA and IgG production. Stimulation with rBanLec can be beneficial in prevention of pathologies raised due to inappropriate cell-mediated immune response as well as in prevention of the pathogen invasion via the colon.

Banana lectin (BanLec) exhibits specificity to glucose/mannose residues present in oligo saccharides or glycoconjugates and has attracted a lot of attention recently as a potent therapeutic agent. Structural studies and molecular cloning methods has revealed the presence of three different BanLec proteins in two species. In our study, initial mass spectrometric analysis of affinity purified native BanLec from banana pulp (Musa paradisiaca) indicated the presence of proteins with different molecular mass. Through the bottom up and top down analysis we identified three major isoforms with acetylation at N terminus. Especially, top down analysis revealed one isoform being present as non acetylated species. The combination of mass spectrometry approaches provided insights on genetic variants and differential modifications in native BanLec. [ABSTRACT FROM AUTHOR]

Glycan–lectin interactions are commonly observed in nature. Analytical methods, which are used to detect lectins that rely on the use of glycan ligand-modified nanoprobes as affinity probes, have been developed. Most of the existing methods are focused on the use of synthetic glycan ligands. Nevertheless, naturally available glycoproteins, such as ovalbumin in chicken egg whites, are good sources for fabricating glycan-immobilized nanoprobes. In this study, we generated functionalized gold nanoparticles (Au NPs) from a one-pot reaction by reacting chicken egg white (cew) proteins with aqueous tetrachloroaurate. The generated Au@cew NPs are mainly encapsulated by ovalbumin, in which the surface is decorated by abundant hybrid mannose and Galβ(1→4)GlcNAc-terminated glycan ligands. Thus, the generated Au@cew NPs containing hybrid mannose and Galβ(1→4)GlcNAc have the capability to selectively bind with their corresponding lectins. Lectins including concanavalin A, banana lectin, and ricin B that have binding moieties toward specific sugars were used as the model samples. Our results showed that the generated AuNPs can be used as multiplex affinity probes for these model lectins. Lectins can be selectively released from the Au@cew NP-lectin conjugates by using specific sugars, such as mannose, glucose, and β-lactose, as the releasing agents to release specific lectins from the conjugates. Matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS) was used as the tool to characterize the released species from the nanoprobes. The limit of detection of these model lectins using the current approach was low (in nM). The feasibility of using the Au@cew NP-based affinity MALDI-MS to selectively detect specific lectins from complex samples was also demonstrated. [ABSTRACT FROM AUTHOR]

Recombinant banana lectin isoform (rBanLec) attaches specifically to the mucosal surface, crosses the epithelial barrier and then directly affects the immune response in mouse colon. Structural characteristics, specificity and physiological impacts of rBanLec reported until now highly resemble those of its natural counterpart. Here, we demonstrated that a dose-dependent stimulation of the colon with rBanLec skewed the immune response towards Th1/Th17 direction and this effect was counterbalanced by the rise in IL-10 production. Qualitative and quantitative characteristics of the established cytokine network were dependent on the applied rBanLec concentration. In addition, rBanLec enhanced local NO production and myeloperoxidase activity and promoted an increase in local IgA and IgG production. Stimulation with rBanLec can be beneficial in prevention of pathologies raised due to inappropriate cell-mediated immune response as well as in prevention of the pathogen invasion via the colon. [ABSTRACT FROM AUTHOR]

Abstract: The sequence of unfolding events of dimeric banana lectin (Banlec), as induced by guanidine hydrochloride (GdnHCl), has been investigated by size-exclusion HPLC, fluorescence, far-UV CD, low temperature phosphorescence and selective chemical modification. 8-Anilino-1-naphthalenesulfonate (ANS) binding indicates a structured unfolding intermediate which has been characterized as dissociated monomer by size-exclusion chromatography. Interestingly, the unfolding elution pattern reveals two distinct unfolded states. One is a usual random coil. The other represents a novel species having elution behavior and structural compactness (Stokes radius) similar to dissociated monomer but showing no regular secondary structure as determined by far-UV CD, thus resembling a natively unfolded state. N-Bromosuccinimide (NBS) oxidation shows that single tryptophan residue remains unmodified in dissociated monomer intermediate while the same is oxidized in natively unfolded-like species. Such difference in tryptophan environment in these species is supported by acrylamide quenching studies, and phosphorescence results at 77 K which show a blue-shift of (0,0) band from 414.8 nm to 409.2 nm. The present results reveal subtlety of structural characteristics of unfolded states of Banlec in GdnHCl, which provide important insight in protein unfolding reaction. [Copyright &y& Elsevier]

Banana lectin (BanLec) was isolated from slightly overripe bananas (PCI 6-7) by homogenation in NaCl solution, followed by extraction in the presence of glucose, ammonium sulfate precipitation, and affinity chromatography. Yields were approximately 10-fold greater that those of previously published methods using acidic extraction from very overripe fruit (Peel Color Index [PCI] 7+). By dilution of added isotopically labeled recombinant lectin, the content of total exchangeable BalLec was shown to be constant or to slightly decrease with increasing stage of ripeness, even though extractable BanLec increased, followed by rapid decrease in overripened fruit. In the course of this study we observed that recombinant BanLec expressed in Escherichia coli, although chemically and functionally identical to native BanLec, differed slightly in its apparent molecular size on gel filtration, probably due to differences in its native folding. [ABSTRACT FROM AUTHOR]

Abstract: Lectins as carbohydrate-binding proteins have been employed in various biological assays for the detection and characterization of glycan structures on glycoproteins, including clinical biomarkers in disease states. A mannose-specific banana lectin (BanLec) is unique in its specificity for internal α1,3 linkages as well as β1,3 linkages at the reducing termini. The immunomodulatory potential of natural BanLec was recognized by a strong immunoglobulin G4 antibody response and T cell mitogen activity in humans. To explore its applicability in glycoproteomics and its modulatory potential, the gene of banana lectin was cloned, sequenced and a recombinant protein was produced in Escherichia coli. The obtained cDNA revealed a novel banana lectin isoform, with an open reading frame of 426 nucleotides, encoding a cytoplasmatic protein of 141 amino acids. The molecular mass of rBanLec determined by ESI FT-MS and N-terminal sequencing confirmed the cDNA at the protein level. The specificity of rBanLec for detection glycan structures was the same as for natural BanLec as examined with five protein extracts rich in glycoprotein content, as well as with horseradish peroxidase glycoprotein. Besides, the immunomodulatory potential of rBanLec and nBanLec were comparable as assessed by an inhibition assay and a human T cell proliferation assay where they induced a strong proliferation response in CD3+, CD4+, and CD8+ populations of human PBMCs. This recombinant BanLec is a useful reagent for glycoproteomics and lectin microarrays, with a potential for modulation of the immune response. [Copyright &y& Elsevier]

Summary: Dietary lectins play a major role in the activation of mast cells / basophils by bridging cell surface IgE glycans to release histamine and other mediators. In the present study, the effect of mannose / glucose-specific banana lectin (BanLec) on the activation of mast cells / basophils from non-atopic and atopic subjects has been investigated. BanLec was purified from banana pulp in a yield of 7 mg/kg. Leukocytes isolated from heparinized blood of non-atopic / atopic subjects were used for quantitation of the released histamine. Approximately 28.2% of the atopics (n = 117) was positive by skin prick test (SPT) to purified BanLec (100 µg/mL concentration), and all the non-atopics (n = 20) were negative. Maximal release of histamine was seen at 2 µg of BanLec. In percent histamine release, an increase of 35-40% is observed in case of atopics (n = 7) compared to non-atopics (n = 5), and the histamine release from atopic and non-atopic subjects correlates fairly well with the total serum IgE levels (R2 = 0.817). BanLec also induces release of histamine (26.7%) from mast cells present in rat peritoneal exudate cells. BanLec can significantly activate and degranulate mast cells and basophils by cross-linking the trimannosidic core mannose of IgE glycans in atopic population as compared to non-atopic population; the activation is marginal in the case of non-atopics.