Immunoregulatory Peptides Research Articles

A New IL-6-Inducing Mechanism in Cancer with New Therapeutic Possibilities.

Background: Interleukin-6 is dysregulated in multiple pathological conditions, e.g., cancer and inflammatory diseases. Aim: To investigate new mechanisms for the regulation of pathological IL-6 production. Methods: PBMCs (peripheral blood mononuclear cells) stimulated by cancer serum factors or specific peptides produce interleukin-6 (IL-6). Immunoregulatory albumin neo-structures and peptides were identified with 2D gel electrophoresis and MALDI-TOF-MS (matrix-assisted laser desorption/ionization time-of-flight mass spectrometry) analyses. Il-6 and albumin neo-structures were determined by ELISA (enzyme-linked immunosorbent assay). Results: Conformational changes in normal serum albumin by proteolytic degradation generates an IL-6-inducing neo-structure, IL-6-inducing factor (IL-6IF). This neo-structure is immunogenic which results in the production of autoantibodies. IL-6 production induced by IL-6IF and cancer patient sera is inhibited by specific antibodies. The serum concentration of IL-6IF is significantly higher in advanced cancer stages, and its presence is significantly correlated with the survival of the patients. Conclusions: A new mechanism for the induction IL-6 synthesis is presented. Based on this mechanism, the pathological IL-6 production related to enhanced proteolytic activity can be diagnosed and selectively inhibited by specific antibodies. Such antibodies were identified and purified. Thus, the neo-structure, inducing pathological IL-6 production, associated with a reduced survival of cancer patients, can be selectively removed by the therapeutic administration of antibodies leaving the function of IL-6 needed for the normal activity of the immune system intact.

Effect of In Vitro Digestion on Bioactive Peptides Related to Immune and Gut Health in Intact Cow's Milk and Hydrolyzed Protein-Based Infant Formulas.

Background/Objectives: Human milk is the optimal source of nutrition and protection against infection for infants. If breastfeeding is not possible, standard and hydrolyzed infant formulas (IF) are an alternative. Extensively hydrolyzed IFs (eHFs) contain bioactive peptides, but their activities have rarely been evaluated. The aim of this study was to characterize and compare the bioactive peptide profiles of different eHFs and standard IFs before and after in vitro digestion. Methods: Two forms, liquid and powder, of intact protein formula (iPF) and eHF were subjected to in vitro gastrointestinal digestion, mimicking a young infant's gut (age 0-4 months) and an older infant's gut (>6 months). Bioactive peptides of in vitro digested and undigested formulas were analysed with Liquid Chromatography-Mass Spectrometry (LC-MS). Results: In all samples, a variety of peptides with potential bioactive properties were found. Immuno-regulatory peptides, followed by antimicrobial and antioxidative peptides were most frequent, as were peptides promoting wound healing, increasing mucin secretion, regulating cholesterol metabolism, and preventing bacterial infection. Peptides typically found in yoghurt and colostrum were identified in some formula samples. Conclusions: The high amounts of bioactive peptides with various properties in eHFs and iPFs indicate a possible contribution to infection protection, healthy gut microbiomes, and immunological development of infants. eHFs showed similar compositions of bioactive peptides to iPFs, with intermittently increased peptide variety and quantity.

Study on the structure–activity relationship of rice immunopeptides based on molecular docking

Research on food-derived immunoregulatory peptides has attracted increasing attention of scientists worldwide. However, the structure–activity relationship of rice immunopeptides was not clearly. Herein, 114 rice immunopeptides were obtained by simulating the enzymatic hydrolysis of rice proteins and were further analyzed by NetMHCIipan-4.0. Subsequently, the molecular docking was used to simulate the binding of immunoreactive peptides to major histocompatibility complex class II (MHC-II) molecules. Results show that S, R, D, E, and T amino acid could easily form hydrogen bonds with MHC-II molecules, thus enhancing innate and adaptive immunity. Finally, glucose-modified rice immunopeptides were to investigate the binding of the peptides with MHC-II molecules after glycosylation modification; this provided a theoretical basis for the targeted modification of the generated immunopeptides. All in all, the present study provides a theoretical foundation to further utilize rice processing byproducts and other food products to enhance immunity.

Purification and characterization of a novel immunoregulatory peptide from Sipunculus nudus L. protein.

This study aimed to purify and characterize immunoregulatory peptides from Sipunculus nudus L. and to explore the underlying mechanisms. Ultrafiltration, gel filtration chromatography, and reverse phase high-performance liquid chromatography (RP-HPLC) were used to purify the peptide following enzymatic hydrolysis. Rates of lymphocyte proliferation and phagocytosis as well as nitric oxide (NO) production levels were used as indicators of immunoregulatory activity to screen the fractions. The amino acid sequence of the peptide, designated as SNLP, was identified as Arg-Val-Lys-Gly-Lys-Ile-Leu-Ala-Lys-Arg-Leu-Asn (RVKGKILAKRLN) by liquid chromatography-tandem mass spectrometry (LC-MS/MS). Treatment with the synthetic SNLP increased the proliferation and phagocytosis of RAW 264.7 macrophages and promoted the secretion of tumor necrosis factor-ɑ (TNF-α), interleukin-6 (IL-6), interleukin-1β (IL-1β), and NO levels. The mRNA levels of these cytokines and iNOS were also increased by SNLP. Our results provide preliminary evidence suggesting that SNLP acts as a dual immunomodulatory peptide with immunostimulatory and anti-inflammatory activities. In summary, SNLP derived from Sipunculus nudus L. is a potent immunoregulatory peptide and represents a potential functional food or immunoregulatory drug.

Analysis of cytokine response characteristics and immunopathogenetic effects of double-stranded sodium salt RNA-based drug for postexposure prophylaxis against novel coronavirus infection: double-blind, placebo-controlled trial

The aim of the work was to study сytokine response characteristics in the group of persons contacted by a novel coronavirus infection depending on the development of the disease over the next 14 days. Herewith, for the immunocorrection with a preparation based on RNA double-stranded sodium salt (RADAMIN®VIRO) causing a secondary reduction in the risk of COVID-19 in the analyzed group, potential targets had been selected.Materials and methods. A double-blind, placebo-controlled study of the drug based on RNA double-stranded sodium salt therapeutic effects was conducted in a group of patients who had been in contact with the persons having a confirmed diagnosis of COVID-19. The method of enzyme immunoassay in dynamics was used to determine the content of interferons alpha and beta (IFNα and IFNβ, respectively), interleukin-1β and -10 (IL1β and IL-10, respectively) in the blood serum and saliva in the contact persons, with a retrospective assessment of changes depending on the administration of the drug or placebo, as well as the development of COVID-19.Results. In the course of the presented study, it was demonstrated that the established content of IFNα (less than 28 pg/ml) and IFNβ (less than 12 pg/ml) in saliva on the 1st–2nd contact days is a predictor of an increased risk of developing COVID-19. Herewith, the increase degree in these immunoregulatory peptides in the interval of 2–3 contact days is important: IFNα and IFNβ allows leveling the negative prognosis in patients by 250% or more. The lowest rates (p <0.001) of INFα on the 1st–2nd contact days, as well as an increase of less than 21% by the 3rd day, were observed in persons with a waist circumference of more than 80/94 cm (women/men). The incidence in this group was higher and amounted to 85% (16 out of 20 people). The predictor role of IL-1β and IL-10 in the blood and saliva in relation to the start of the infectious process was not revealed. The administration of drug based on RNA double-stranded sodium salt to the contact patients made it possible to correct the interferon response in the form of an increase in the content of IFNα and IFNβ, as well as to reduce the incidence in comparison with the placebo group.Conclusion. Differences in the interferon regulation upon contact with SARS-CoV-2 in the form of lower INF α and β levels, as well as a slightly pronounced growth dynamics in the interval of the first 3 days, influenced the increased risk of developing COVID-19. RADAMIN®VIRO can be recommended as a means of post-exposure prophylaxis of COVID-19 for both medical institutions and for caregivers and / or contacts with COVID-19 patients.

Natural and synthetic peptides in antimicrobial therapy

Antimicrobial function of innate immunity is mediated by the low-molecular weight peptides which are active against bacteria, fungi and some viruses. The review presents data on studies of both natural and synthetic peptides regarding the features of their structure and therapeutic effect. As a rule, the molecules of such peptides are positively charged, due to amino acid radicals capable of protonation. Spatially, antimicrobial peptide molecules are arranged as -helices or -layers in separate or compound assemblies. At the same time, short molecular chains, including up to 18 amino acid residues, exist as a linear or cyclic forms, remaining at the level of primary spatial structure. Natural antimicrobial peptides are predominantly produced by neutrophilic granulocytes and macrophages, as well as epithelial cells of the barrier organs. Three families of natural antimicrobial peptides have been most studied: defensins, cathelicidins, and histatins. Defensins are active against Gram-positive and Gram-negative bacteria, viruses and fungi, having anti-inflammatory and immunomodulatory activity. Cathelicidins are chemoattractants and exert antibacterial, immunomodulatory, wound healing, antitumor effects, potentially contributing to the development of autoimmune diseases. Histatins have a pronounced fungicidal effect and prevent the formation of bacterial biofilms. A detailed study on the structure and principles of action of natural antimicrobial peptides made it possible to apply this information for the in vitro synthesis of peptides thus making it possible to create multipurpose drugs based on them. E.g., synthetic peptides WR12 and D-IK8 ensure the delivery of antibiotics to infected or tumor cells, due to permeabilization of cellular membranes. At the same time, a synthetic peptide, acipensin 1, is capable of penetrating into human tumor cells without damaging them. The immunomodulatory peptide glutoxim is effectively used in anti-tuberculosis therapy. ZP2 peptide, the functional site of granulocyte-macrophage colony-stimulating factor is effective against Gram-negative bacteria (K. pneumoniae, P. aeruginosa and A. baumannii) as well as EpsteinBarr virus. Thymic immunoregulatory peptides bestim, hepon, thymogen and imunofan are inducers of endogenous - and -interferon production, inhibit the development of malignant neoplasms, and possess anti-inflammatory activity. Gepon is used in the treatment of viral hepatitis, respiratory and opportunistic infections, croup syndrome and sexually transmitted infections (including genital herpes). Thus, the synthetic antimicrobial peptides are widely used in complex treatment regimens along with conventional antibiotics, antiviral, and antitumor drugs, thus making it possible to achieve higher therapeutic effect.

Structure and activity of bioactive peptides produced from soybean proteins by enzymatic hydrolysis

Peptides are good food stabilizers and thickeners. They also present good bioactivities. The structure characteristics of peptides are related to the health benefits. In this study, immunoregulatory peptides were produced by Alcalase® and neutrase hydrolysis of soybean proteins. UHPLC-MS/MS was applied for structure identification. The immumoregulatory activities and mechanisms were investigated. Eighty five peptides were identified from the hydrolysates and 84 peptides might be immunoregulatory peptides. Most of them were novel immunoregulatory peptides. These peptides had good immunoregulatory activities, including increasing the pinocytotic capacity, and inducing the production and genes expression of NO, IL-6 and TNF-α in a dose-dependent manner. Specific inhibitors of NF-κB and JNK could significantly suppress NO production stimulated by soybean peptides, implying that NF-κB and JNK pathways were involved in their immunoregulatory mechanisms. Our results suggested that the soybean peptides prepared in this study were promising immunomodulatory neutraceuticals.

LTBK-03. Targeted mass spectrometry of serial CSF and serum specimens from children with diffuse intrinsic pontine glioma treated with intracranial B7-H3 CAR T cells

Considering the high expression of B7-H3 (CD276) on diffuse intrinsic pontine glioma (DIPG) and preliminary evidence that repeated locoregional delivery of CAR T cells to patients with CNS tumors was feasible and tolerable, we open the phase 1 trial BrainChild-03 (NCT04185038). Children with DIPG in Dose Regimen 1 received 40 intraventricular B7H3CAR doses, with the two patients enrolling post-progression surviving >400 days from initial CAR T infusion. To evaluate for immune and tumor responses that may correlate with clinical and radiographic evaluations, we performed targeted proteomic analysis on serial CSF and serum biospecimens.MRM-MS is a targeted mass spectrometry that provides sensitive measurement of proteins in cancer tissues and fluids. In 2 patients with longitudinal biospecimens, we identified 50 CSF and 59 serum proteins above level of detection. In general, there were fewer serum fluctuations compared to the CSF, supporting that intracranial delivery provides local immune activation. Sharp fluctuations of several immunoregulatory peptides were measured in the CSF at pre and post infusion timepoints, including BCL10, CXCL13, TIM-3, ICOSLG, and PD-L2. Notably, several analytes tracked consistently in the CSF of both patients, including markers of macrophage maturation and immune cell recruitment, including CD14, CD163, CD44, CSF-1, CXCL13 and VCAM-1. B7-H3 was detected in the CSF and serum of both patients. S005, who progressed on protocol therapy, had a sharp increase in B7-H3 in the CSF during Course 2, while S008, who had clinical improvement on protocol therapy, had consistently lower B7-H3 present. Notably, serum B7-H3 steadily declined in both patients over time, with the exception of a transient increase in S005 between Courses 4 and 5. Future work for all enrolled patients with DIPG will explore the correlation of these targeted proteomic measurements with clinical end points for potential use as markers of efficacy of therapy or adverse events.

Tiger 17 and pexiganan as antimicrobial and hemostatic boosters of cellulose acetate-containing poly(vinyl alcohol) electrospun mats for potential wound care purposes

In this research, we propose to engineer a nanostructured mat that can simultaneously kill bacteria and promote an environment conducive to healing for prospective wound care. Polyvinyl alcohol (PVA) and cellulose acetate (CA) were combined at different polymer ratios (100/0, 90/10, 80/20% v/v), electrospun and crosslinked with glutaraldehyde vapor. Crosslinked fibers increased in diameter (from 194 to 278 nm), retaining their uniform structure. Fourier-transform infrared spectroscopy and thermal analyses proved the excellent miscibility between polymers. CA incorporation incremented the fibers swelling capacity and reduced the water vapor and air permeabilities of the mats, preventing the excessive drying of wounds. The antimicrobial peptide cys-pexiganan and the immunoregulatory peptide Tiger 17 were incorporated onto the mats via polyethylene glycol spacer (hydroxyl-PEG2-maleimide) and physisorbed, respectively. Time-kill kinetics evaluations revealed the mats effectiveness against Staphylococcus aureus and Pseudomonas aeruginosa. Tiger 17 played a major role in accelerating clotting of re-calcified plasma. Data reports for the first time the collaborative effect of pexiganan and Tiger 17 against bacterial infections and in boosting hemostasis. Cytocompatibility data verified the peptide-modified mats safety. Croslinked 90/10 PVA/CA mats were deemed the most promising combination due to their moderate hydrophilicity and permeabilities, swelling capacity, and high yields of peptide loading.

Prediction of SARS-CoV-2 Omicron Variant Immunogenicity, Immune Escape and Pathogenicity, through the Analysis of Spike Protein-Specific Core Unique Peptides.

The recently discovered Omicron variant of the SARS-CoV-2 coronavirus has raised a new, global, awareness. In this study, we identified the Core Unique Peptides (CrUPs) that reside exclusively in the Omicron variant of Spike protein and are absent from the human proteome, creating a new dataset of peptides named as SARS-CoV-2 CrUPs against the human proteome (C/H-CrUPs), and we analyzed their locations in comparison to the Alpha and Delta variants. In Omicron, 115 C/H-CrUPs were generated and 119 C/H-CrUPs were lost, almost four times as many compared to the other two variants. At the Receptor Binding Motif (RBM), 8 mutations were detected, resulting in the construction of 28 novel C/H-CrUPs. Most importantly, in the Omicron variant, new C/H-CrUPs carrying two or three mutant amino acids were produced, as a consequence of the accumulation of multiple mutations in the RBM. These C/H-CrUPs could not be recognized in any other viral Spike variant. Our findings indicated that the virus binding to the ACE2 receptor is facilitated by the herein identified C/H-CrUPs in contact point mutations and Spike cleavage sites, while the immunoregulatory NF9 peptide is not detectably affected. Thus, the Omicron variant could escape immune-system attack, while the strong viral binding to the ACE2 receptor leads to the highly efficient fusion of the virus to the target cell. However, the intact NF9 peptide suggests that Omicron exhibits reduced pathogenicity compared to the Delta variant.

Изменение содержания цитокинов семейства IL1 в крови больных эссенциальной гипертензией после COVID-19

Pathogenetic progression mechanisms in the SARS-CoV-2–essential hypertension (EAH) system are more complex than interaction at the level of angiotensinconverting enzyme 2 (ACE2). The study was aimed to assess the dynamic changes of the IL1 members (IL1β, IL1α, IL1ra, IL18, IL18BP, IL37) blood levels in patients with EAH 10, 30, and 180 days after having COVID-19 in order to define cytokine-mediated mechanisms of EAH progression during the period following infection. The study involved four groups of patients: with a history of EAH and COVID-19 (pneumonia/no pneumonia), with a history of COVID-19 (pneumonia/no pneumonia) and no EAH. Cytokine levels were determined by enzyme immunoassay. The study results demonstrate the prolonged proinflammatory immune response during the period following infection in patients with EAH (retaining higher levels of IL1β, IL1α, and IL18 on days 10, 30, and 180 after recovery (р < 0.001) compared to levels measured prior to SARS-CoV-2 infection). In the group with no EAH, the balance of assayed cytokines was restored on day 30 of follow-up. The two-fold increase of blood IL18 levels in patients, having a history of EAH and COVID-19 and showing no increase in the IL18ВР levels after 30 days of follow up compared to the values measured prior to infection, is associated with cardiovascular complications occurring during the first six months of follow-up. This makes it possible to hypothesize the importance of these immunoregulatory peptides for the pathogenesis of complications and enhances the relevance of further scientific research.

Cytokines and growth factors in a biologic product obtained from patients' urine as immune-modulators to treat autoimmune and allergic diseases

At “Instituto de Alergias y Autoinmunidad Dr. Maximiliano Ruiz Castañeda, A.C.” in Mexico City, a non-traditional health care center focused on the treatment of autoimmune and allergic diseases using personalized medicine, an alternative treatment referred to as an “immune-modulator” has been developed. In this study, we will refer to this treatment substance as the “immune-modulator.” In brief, a urine sample is collected from the patient and processed to obtain the peptide fraction, which is conditioned and then administered sublingually to the patient. Sample processing involves multiple steps aimed at the removal of toxic compounds and enrichment for cytokines, growth factors, and other immune peptides that may contribute to the function of the immune-modulator. This treatment has been administered for many years, and patients testify that it is useful and reliable. Despite the benefits of this treatment, the molecular mechanisms underlying its effects have not been thoroughly investigated. Therefore, this study aims to identify immunoregulatory peptides, such as cytokines and growth factors, in the immune-modulator.Urine and immune-modulator concentrations of cytokines and growth factors were assessed using a Luminex assay.Twenty-one cytokines and growth factors were identified in immune-modulator samples. MCP-1 was identified in 100% of the samples; MIP-1β, IL-8, RANTES, INF-γ, and IP-10 were identified in approximately 65–70% of samples; IL5, IL-1B, and IL-17 in 50–60%; eotaxin, VEGF, IL-6, and FGF in about 40%; MIP-1α, IL-9, GM-CSF, G-CSF, IL-12, and IL-15 in about 20–30%; and IL-13 and PDGF-bb were identified in <6% of samples. Additionally, patients exhibited significant changes in IL-1β, IFN-γ, and MCP-1 concentrations after treatment with the immune-modulator, whereas healthy individuals showed no significant change in response to the treatment.The immune-modulator is an alternative treatment based on the administration of cytokines and growth factors obtained from the urine of patients. In this study, its composition was characterized. The isolated products could be responsible for the effects of the immune-modulator. Further trials are required to evaluate the effective delivery of these molecules by the administration route described.

Early Treatment with a Peptide Derived from the Human Heat-Shock 60 Protein Avoids Progression to Severe Stages of COVID-19

Hyperinflammatory response induced by SARS-CoV-2 characterizes COVID-19 patients progressing to severe conditions. CIGB-258 is an immunoregulatory peptide with anti-inflammatory properties derived from the human stress protein 60 (HSP60). This peptide has been used in the treatment of serious and critically ill COVID-19 patients with positive results. This study is aimed to describe the outcomes of a cohort of moderately ill COVID-19 patients treated with CIGB-258. Clinical assessment and inflammation biomarkers indicated that these patients were progressing to the hyperinflammation phase. In addition, this study displays the outcomes of two other cohorts of COVID-19 patients in serious and critical conditions, treated with this molecule. One hundred and four patients with COVID-19 in moderate (18.3%), serious (60.6%) and critical (21.1%) conditions were enrolled in this study. None of the moderate patients progressed to the severe stage of the disease. Out of sixty-three seriously ill patients, only eleven progressed to a critical condition. These patients had several comorbidities that aggravated their clinical conditions.

Expression and purification of ShLysG in Escherichia coli and initial characterization of its antimicrobial, antioxidant and anti-inflammatory activities

ShLysG is a novel g-type lysozyme isolated from Hippocampus abdominalis in 2016. However, its antibacterial, antioxidant and anti-inflammatory properties have not been investigated. In this study, a recombinant ShLysG (rShLysG) fused with a 6×His tag was produced in Escherichia coli with barely any hemolytic activity or cytotoxicity. It exhibited a broad antimicrobial spectrum against gram-positive and gram-negative bacteria with minimum inhibitory concentration (MIC) values between 20 and 60 μg/mL. The bioactivity of rShLysG was stable in high temperature and extreme acid base conditions. In addition, rShLysG was resistant to papain and pepsin, and it showed a concentration-dependent antioxidant activity. By inhibiting the phosphorylation of NF-κB, the inflammatory cytokines expression level, including TNF-α, IL-6, and IL-8 in RAW264.7 macrophage cells induced by LPS were decreased. Taken together, rShLysG is a promising substitute to antibiotics as an antimicrobial and immunoregulatory pharmaceutical peptide for clinical use.

Preparation and purification of an immunoregulatory peptide from Stolephorus chinensis of the East Sea of China

Immunomodulatory peptides derived from marine organisms are potential sources of new immunomodulating drugs. This study aimed to investigate the optimal enzymatic hydrolysis conditions of immunoregulatory peptides from Stolephorus chinensis. The relative proliferation rate (RPR) of RAW264.7 macrophages was set as the screening index. The immunoregulatory peptides from S. chinensis was prepared via process optimization, ultrafiltration, ion-exchange chromatography, and reverse-phase high-performance liquid chromatography (RP-HLPC). The amino acid sequence of the immunoregulatory peptide from S. chinensis (IPSC) was identified to be Tyr-Val-Met-Arg-Phe (YVMRF; MW 715.4 Da) using Edman degradation and mass spectrometry. In addition, the macrophages became larger with more pseudopods after IPSC treatment, indictating that IPSC stimulated RAW 264.7 differentiation. IPSC also increased productions of nitric oxide (NO), interleukin-6 (IL-6), interleukin-1β (IL-1β), and tumor necrosis factor-α (TNF-α). Our results provide a theoretical basis for preparing immunomodulatory functional food from S. chinensis in future.

Plasma levels of DPP4 activity and sDPP4 are dissociated from inflammation in mice and humans

Dipeptidyl peptidase-4 (DPP4) modulates inflammation by enzymatic cleavage of immunoregulatory peptides and through its soluble form (sDPP4) that directly engages immune cells. Here we examine whether reduction of DPP4 activity alters inflammation. Prolonged DPP4 inhibition increases plasma levels of sDPP4, and induces sDPP4 expression in lymphocyte-enriched organs in mice. Bone marrow transplantation experiments identify hematopoietic cells as the predominant source of plasma sDPP4 following catalytic DPP4 inhibition. Surprisingly, systemic DPP4 inhibition increases plasma levels of inflammatory markers in regular chow-fed but not in high fat-fed mice. Plasma levels of sDPP4 and biomarkers of inflammation are lower in metformin-treated subjects with type 2 diabetes (T2D) and cardiovascular disease, yet exhibit considerable inter-individual variation. Sitagliptin therapy for 12 months reduces DPP4 activity yet does not increase markers of inflammation or levels of sDPP4. Collectively our findings dissociate levels of DPP4 enzyme activity, sDPP4 and biomarkers of inflammation in mice and humans.

Comparison of Thymulin Activity with Other Measures of Marginal Zinc Deficiency.

Activity of the immunoregulatory peptide thymulin reflects differences in zinc status. This study compared thymulin activity with four other zinc status measures in rats fed zinc at either 5 or 25ppm. Rats fed the lower zinc showed the following results compared with rats with adequate zinc intake: serum thymulin activity 61% lower, serum zinc 31% lower, serum extracellular superoxide dismutase 18% lower, serum 5'-nucleotidase activity 26% lower, and liver metallothionein 28% lower. Thus, thymulin activities showed more sensitivity to restricted zinc intake than did four other parameters.

Overcoming Shellfish Allergy: How Far Have We Come?

Shellfish allergy caused by undesirable immunological responses upon ingestion of crustaceans and mollusks is a common cause of food allergy, especially in the Asia-Pacific region. While the prevalence of shellfish allergy is increasing, the mainstay of clinical diagnosis for these patients includes extract-based skin prick test and specific IgE measurement while clinical management consists of food avoidance and as-needed use of adrenaline autoinjector should they develop severe allergic reactions. Such a standard of care is unsatisfactory to both patients and healthcare practitioners. There is a pressing need to introduce more specific diagnostic methods, as well as effective and safe therapies for patients with shellfish allergy. Knowledge gained on the identifications and defining the immuno-molecular features of different shellfish allergens over the past two decades have gradually translated into the design of new diagnostic and treatment options for shellfish allergy. In this review, we will discuss the epidemiology, the molecular identification of shellfish allergens, recent progress in various diagnostic methods, as well as current development in immunotherapeutic approaches including the use of unmodified allergens, hypoallergens, immunoregulatory peptides and DNA vaccines for the prevention and treatment of shellfish allergy. The prospect of a “cure “for shellfish allergy is within reach.

The purification and identification of immunoregulatory peptides from oyster (Crassostrea hongkongensis) enzymatic hydrolysate.

Oysters, favored as a delicious seafood by people worldwide, contain various nutritional components, especially proteins. In this work, the immunoregulatory peptides were isolated and purified from oyster enzymatic hydrolysate by utilizing anion exchange chromatography and RP-HPLC, and were identified via LC-MS/MS. A proliferation assay, a phagocytosis assay, and TNF-α production, NO production and IL-6 production assays were used to examine the immunoregulatory effects of the two identified peptides. The results indicate that the peptides, DNSIAMESMK (P1) and LLQLGSGR (P2), increased the proliferation rate of macrophages, TNF-α and NO production, IL-6 production, and the phagocytosis ability, but to different degrees; P2, with more hydrophobic amino acids, was more potent than P1. This suggested that these peptides might be potential candidates for developing immunoregulatory functional foods and nutraceuticals.

Hyaluronidase activity in the salivary glands of tabanid flies

Tabanids are haematophagous insects that act as biological and mechanical vectors of various diseases, including viruses, bacteria and parasites. The saliva of these insects contains strong anticoagulant and vasodilatory activities as well as immunoregulatory peptides. Here we demonstrate pronounced hyaluronidase (hyase) activity in ten tabanid species of the genera Chrysops, Haematopota, Hybomitra and Tabanus. Compared to other haematophagous insects, the ability of tabanid hyases to hydrolyze hyaluronic acid (HA) is extremely high, for example the enzyme activity of Hybomitra muehlfeldi was found to be 32-fold higher than the salivary hyase activity of the sand fly Phlebotomus papatasi. Hyases of all ten tabanid species tested also cleaved chondroitin sulfate A, another glycosaminoglycan present in the extracellular matrix of vertebrates. The pH optimum of the enzyme activity was measured in eight tabanid species; the hyase of Haemopota pluvialis was the only one with optimum at pH 4.0, while in the other seven species the activity optimum was at 5.0. SDS PAGE zymography showed the monomeric character of the enzymes in all tabanid species tested. Under non-reducing conditions the activities were visible as single bands with estimated MW between 35 and 52 kDa. The very high hyaluronidase activity in tabanid saliva might be related to their aggressive biting behavior as well as to their high efficiency as mechanical vectors. As they are supposedly involved in the enlargement of feeding hematomas, hyases might contribute to the mechanical transmission of pathogens. Pathogens present in vector mouthparts are co-inoculated into the vertebrate host together with saliva and may benefit from increased tissue permeability and the immunomodulatory activity of the salivary hyase.