ABSTRACT
Alpha-Gal syndrome (AGS) manifests as an intricate allergic response characterised by the formation of specific immunoglobulin E (IgE) antibodies targeting a carbohydrate termed galactose-a-1.3-galactose (a-Gal). Alpha-Gal antigens, which play a role in AGS, have been detected in the salivary glands and saliva of various tick species, especially Amblyomma americanum. Identifying these antigens in tick saliva underlines the potential role of tick bites in sensitising individuals to a-Gal and contributes to the complex immunological processes associated with AGS. When people with a-Gal allergy eat beef, pork, lamb, or the flesh of other mammals, they experience an allergic reaction that causes various symptoms, including rash, nausea, vomiting, and diarrhoea. In some cases, AGS can be life-threatening requiring emergency medical attention. Moreover, these reactions do not occur only due to red meat; intake of medical drugs, vaccines, and antidotes containing a-Gal epitopes can also trigger allergies. The fact that the symptoms causing IgE antibodies are directed against a carbohydrate moiety the unusual delay between food consumption and the onset of symptoms, and the differences in the reactions shown by a-Gal allergy make a-Gal syndrome an unprecedented allergic disease and distinguish it from other food allergies. Interestingly, a-Gal antigens involved in the development of AGS have been discovered in salivary secretions of different tick species in several continents. However, the underlying causes of a-Gal-specific IgE production and immune responses to tick bites are not fully understood. This complex system is crucial for identifying and developing new therapies for the disease. This article reviews the evolution of a-Gal, the current understanding of AGS and its relationship to tick species.
Subject(s)
Food Hypersensitivity , Immunoglobulin E , Tick Bites , Humans , Tick Bites/immunology , Tick Bites/complications , Animals , Food Hypersensitivity/immunology , Immunoglobulin E/immunology , Disaccharides/immunology , Saliva/immunology , Saliva/chemistryABSTRACT
Certain classes of antibiotics, including tetracyclines and macrolides, are known to exert immune suppressive effects in other species but the immune modulatory effects of these antibiotics have not been previously studied in cattle. To address this question, we investigated the effects of oxytetracycline, gamithromycin, and tulathromycin on T cell and macrophage responses to activation, using in vitro assays. In addition, we assessed the impact of these antibiotics on T cell responses in vivo following treatment of healthy cattle with currently recommended doses of each of the three antibiotics. We found that all 3 antibiotics markedly suppressed T cell proliferation in vitro at relevant therapeutic drug concentrations and significantly suppressed macrophage activation responses to LPS. In cattle treated with a single dose of each antibiotic, we observed significant suppression of T cell proliferation and cytokine production beginning as early as 6 h after administration, with increasing immune suppression observed at 48 h. Taken together, these results indicate that commonly used antibiotics in cattle exert significant immune modulatory activity, in addition to their antimicrobial activity. These off-target effects should be considered when using antibiotics for prophylaxis or metaphylaxis in high-risk dairy or beef cattle (192 words).
Subject(s)
Anti-Bacterial Agents , Disaccharides , Heterocyclic Compounds , Oxytetracycline , Animals , Cattle , Oxytetracycline/pharmacology , Heterocyclic Compounds/pharmacology , Anti-Bacterial Agents/pharmacology , Disaccharides/pharmacology , Disaccharides/immunology , T-Lymphocytes/drug effects , T-Lymphocytes/immunology , Macrophages/drug effects , Macrophages/immunology , Macrolides/pharmacology , Cytokines/metabolism , Cell Proliferation/drug effects , FemaleABSTRACT
BACKGROUND: IgE to galactose-alpha-1,3-galactose (alpha-gal) is linked to tick bites and an important cause of anaphylaxis and urticarial reactions to mammalian meat. The alpha-gal syndrome (AGS) is recognized as being common in the southeastern United States. However, prevalence studies are lacking and open questions remain about risk factors and clinical presentation of alpha-gal sensitization. OBJECTIVE: Here we characterized the prevalence as well as the presentation and risk factors of AGS and alpha-gal IgE sensitization in adults in central Virginia recruited without regard to the history of allergic disease. METHODS: Adults in central Virginia, primarily University of Virginia Health employees, were recruited as part of a COVID-19 vaccine study. Subjects provided at least one blood sample and answered questionnaires about medical and dietary history. We used ImmunoCAP for IgE assays and assessed the ABO blood group by reverse typing using stored serum. We also investigated biobanked serum from COVID-19 patients. RESULTS: Median age of the 267 enrollees was 42 years, 76% were female, and 43 (16%) were sensitized to alpha-gal (cutoff of 0.1 IU/mL), of which mammalian meat allergy was reported by seven (2.6%). Sensitized subjects (1) were older, (2) had higher total IgE levels but a similar frequency of IgE to common respiratory allergens, and (3) were more likely to report tick bites than were nonsensitized subjects. Among those who were sensitized, alpha-gal IgE levels were higher among meat-allergic than nonallergic subjects (geometric mean, 9.0 vs 0.5 IU/mL; P < .001). Mammalian meat and dairy consumption was common in individuals with low-level sensitization. CONCLUSION: In central Virginia, AGS is a dominant cause of adult food allergy with a prevalence approaching or exceeding 2%.
Subject(s)
COVID-19 , Food Hypersensitivity , Immunoglobulin E , Humans , Immunoglobulin E/blood , Female , Male , Adult , Virginia/epidemiology , Middle Aged , Food Hypersensitivity/epidemiology , Food Hypersensitivity/immunology , Food Hypersensitivity/diagnosis , COVID-19/immunology , COVID-19/epidemiology , COVID-19 Vaccines/immunology , COVID-19 Vaccines/adverse effects , SARS-CoV-2/immunology , Cohort Studies , Tick Bites/immunology , Tick Bites/epidemiology , Prevalence , Risk Factors , Allergens/immunology , Animals , Meat , Aged , Disaccharides/immunologyABSTRACT
The disaccharide (ß-D-glucopyranosyluronic acid)-(1â4)-ß-D-glucopyranoside represents a repeating unit of the capsular polysaccharide of Streptococcus pneumoniae serotype 3. A conjugate of the disaccharide with BSA (di-BSA conjugate) adjuvanted with aluminum hydroxide induced - in contrast to the non-adjuvanted conjugate - IgG1 antibody production and protected mice against S. pneumoniae serotype 3 infection after intraperitoneal prime-boost immunization. Adjuvanted and non-adjuvanted conjugates induced production of Th1 (IFNγ, TNFα); Th2 (IL-5, IL-13); Th17 (IL-17A), Th1/Th17 (IL-22), and Th2/Th17 cytokines (IL-21) after immunization. The concentration of cytokines in mice sera was higher in response to the adjuvanted conjugate, with the highest level of IL-17A production after the prime and boost immunizations. In contrast, the non-adjuvanted conjugate elicited only weak production of IL-17A, which gradually decreased after the second immunization. After boost immunization of mice with the adjuvanted di-BSA conjugate, there was a significant increase in the number of CD45+/CD19+ B cells, TCR+ γδ T cell, CD5+ Ð1 cells, and activated cells with MHC II+ expression in the spleens of the mice. IL-17A, TCR+ γδ T cells, and CD5+ Ð1 cells play a crucial role in preventing pneumococcal infection, but can also contribute to autoimmune diseases. Immunization with the adjuvanted and non-adjuvanted di-BSA conjugate did not elicit autoantibodies against double-stranded DNA targeting cell nuclei in mice. Thus, the molecular and cellular markers associated with antibody production and protective activity in response to immunization with the di-BSA conjugate adjuvanted with aluminum hydroxide are IL-17A, TCR+ γδ T cells, and CD5+ Ð1 cells against the background of increasing MHC II+ expression.
Subject(s)
Interleukin-17 , Pneumococcal Vaccines , Serum Albumin, Bovine , Streptococcus pneumoniae , Animals , Interleukin-17/immunology , Interleukin-17/metabolism , Streptococcus pneumoniae/immunology , Mice , Serum Albumin, Bovine/immunology , Pneumococcal Vaccines/immunology , Pneumococcal Infections/immunology , Pneumococcal Infections/prevention & control , Disaccharides/immunology , Bacterial Capsules/immunology , Polysaccharides, Bacterial/immunology , Adjuvants, Immunologic/administration & dosage , Female , Antibodies, Bacterial/blood , Antibodies, Bacterial/immunology , Intraepithelial Lymphocytes/immunology , Serogroup , Receptors, Antigen, T-Cell, gamma-delta/immunology , Receptors, Antigen, T-Cell, gamma-delta/metabolismABSTRACT
Delayed anaphylaxis after ingestion of red meat because of galactose-alpha-1,3-galactose (alpha-gal) syndrome has increased in recent years. The mechanism involves an immunoglobulin E reaction to alpha-gal, a molecule found in mammalian meat, dairy products, medications and excipients containing mammalian-derived components, and tick salivary glycans. Sensitization occurs due to the bite of a lone star tick and the transmission of alpha-gal molecules into person's bloodstream. We describe a case of alpha-gal syndrome with severe food, drug, and perioperative allergy in which anaphylaxis with hypovolemic shock occurred immediately after an emergency surgical procedure, when a gelatin-containing drug was injected. This case study confirms that the clinical manifestations of alpha-gal syndrome could be different depending on the route of administration, with immediate reactions if an alpha-gal-containing drug is injected and delayed type allergic manifestations occurring several hours after oral intake. The purpose of this report is to highlight the importance of risk communication in case of exposure to medical products and surgical procedures of patients with alpha-gal syndrome and to encourage drug manufacturers to indicate clearly the origin of excipients in product literature.
Subject(s)
Anaphylaxis , Food Hypersensitivity , Shock , Humans , Anaphylaxis/diagnosis , Anaphylaxis/therapy , Anaphylaxis/etiology , Food Hypersensitivity/diagnosis , Food Hypersensitivity/complications , Food Hypersensitivity/immunology , Shock/etiology , Shock/diagnosis , Drug Hypersensitivity/diagnosis , Drug Hypersensitivity/therapy , Male , Animals , Immunoglobulin E/immunology , Excipients/adverse effects , Disaccharides/immunology , Disaccharides/adverse effects , Female , Trisaccharides/immunology , Gelatin/adverse effects , SyndromeABSTRACT
The recent recognition of a syndrome of tick-acquired mammalian meat allergy has transformed the previously held view that mammalian meat is an uncommon allergen. The syndrome, mediated by IgE antibodies against the oligosaccharide galactose-alpha-1,3-galactose (alpha-gal), can also involve reactions to visceral organs, dairy, gelatin and other products, including medications sourced from non-primate mammals. Thus, fittingly, this allergic disorder is now called the alpha-gal syndrome (AGS). The syndrome is strikingly regional, reflecting the important role of tick bites in sensitization, and is more common in demographic groups at risk of tick exposure. Reactions in AGS are delayed, often by 2-6 h after ingestion of mammalian meat. In addition to classic allergic symptomatology such as urticaria and anaphylaxis, AGS is increasingly recognized as a cause of isolated gastrointestinal morbidity and alpha-gal sensitization has also been linked with cardiovascular disease. The unusual link with tick bites may be explained by the fact that allergic cells and mediators are mobilized to the site of tick bites and play a role in resistance against ticks and tick-borne infections. IgE directed to alpha-gal is likely an incidental consequence of what is otherwise an adaptive immune strategy for host defense against endo- and ectoparasites, including ticks.
Subject(s)
Anaphylaxis , Food Hypersensitivity , Immunoglobulin E , Tick Bites , Tick-Borne Diseases , Urticaria , Animals , Humans , Allergens/immunology , Anaphylaxis/immunology , Anaphylaxis/etiology , Anaphylaxis/diagnosis , Disaccharides/immunology , Food Hypersensitivity/immunology , Food Hypersensitivity/etiology , Immunoglobulin E/immunology , Mammals/immunology , Meat/adverse effects , Syndrome , Tick Bites/immunology , Tick Bites/complications , Ticks/immunology , Urticaria/immunology , Urticaria/etiology , Tick-Borne Diseases/immunologySubject(s)
Immunoglobulins, Intravenous , Small Fiber Neuropathy , Humans , Disaccharides/immunology , Heparin/immunology , Immunoglobulin M , Immunoglobulins, Intravenous/therapeutic use , Receptor, Fibroblast Growth Factor, Type 3/immunology , Small Fiber Neuropathy/immunology , Small Fiber Neuropathy/therapyABSTRACT
BACKGROUND: Treating known risk factors for coronary artery disease (CAD) has substantially reduced CAD morbidity and mortality. However, a significant burden of CAD remains unexplained. Immunoglobulin E sensitization to mammalian oligosaccharide galactose-α-1,3-galactose (α-Gal) was recently associated with CAD in a small observational study. We sought to confirm that α-Gal sensitization is associated with CAD burden, in particular noncalcified plaque. Additionally, we sort to assess whether that α-Gal sensitization is associated with ST-segment-elevated myocardial infarction (STEMI) Methods: We performed a cross-sectional analysis of participants enrolled in the BioHEART cohort study. We measured α-Gal specific-immunoglobulin E antibodies in serum of 1056 patients referred for CT coronary angiography for suspected CAD and 100 selected patients presenting with STEMI, enriched for patients without standard modifiable risk factors. CT coronary angiograms were assessed using coronary artery calcium scores and segmental plaque scores. RESULTS: α-Gal sensitization was associated with presence of noncalcified plaque (odds ratio, 1.62 [95% CI, 1.04-2.53], P=0.03) and obstructive CAD (odds ratio, 2.05 [95% CI, 1.29-3.25], P=0.002), independent of age, sex, and traditional risk factors. The α-Gal sensitization rate was 12.8-fold higher in patients with STEMI compared with matched healthy controls and 2.2-fold higher in the patients with STEMI compared with matched stable CAD patients (17% versus 1.3%, P=0.01 and 20% versus 9%, P=0.03, respectively). CONCLUSIONS: α-Gal sensitization is independently associated with noncalcified plaque burden and obstructive CAD and occurs at higher frequency in patients with STEMI than those with stable or no CAD. These findings may have implications for individuals exposed to ticks, as well as public health policy. Registration: URL: https://www.anzctr.org.au; Unique identifier: ACTRN12618001322224.
Subject(s)
Coronary Artery Disease/etiology , Coronary Artery Disease/immunology , Food Hypersensitivity/complications , Plaque, Atherosclerotic/etiology , Plaque, Atherosclerotic/immunology , ST Elevation Myocardial Infarction/etiology , ST Elevation Myocardial Infarction/immunology , Aged , Animals , Cohort Studies , Computed Tomography Angiography , Coronary Angiography , Coronary Artery Disease/diagnostic imaging , Cross-Sectional Studies , Disaccharides/immunology , Female , Food Hypersensitivity/immunology , Humans , Immunoglobulin E/blood , Immunoglobulin E/immunology , Male , Middle Aged , Plaque, Atherosclerotic/diagnostic imaging , Prospective Studies , Risk Factors , Severity of Illness Index , Vascular Calcification/diagnostic imagingABSTRACT
BACKGROUND: Small fiber neuropathy (SFN) can be associated with autoantibodies, including those of IgM class with specificity for the trisulfated heparan disaccharide (TS-HDS) antigen. We hypothesized that, as an IgM autoantibody-mediated disorder, TS-HDS-associated SFN symptoms may be reduced with therapeutic plasma exchange (TPE). STUDY METHODS: This was an observational analysis of all patients referred for TPE from 2018 to 2020 following laboratory confirmation of SFN with TS-HDS autoantibodies; a loading course of 3 to 5 procedures over 2 weeks was completed, with some patients returning for monthly procedures. The following data were collected: demographics, symptoms and duration, TS-HDS levels, skin biopsy results, reported responses to TPE, and TPE-associated adverse events. RESULTS: Of the 17 subjects, 12 (71%) were female and the mean age was 57.5 years (range 27-94). The most common reported symptom was lower extremity paresthesia (88% of subjects). The mean number of TPE procedures completed per subject was 9 (range 3-18), with 71% (12/17) reporting symptomatic improvement or slowed disease progression. About 15% of procedures were associated with an adverse event, with vasovagal reactions being the most common; 53% of patients had at least one adverse event. CONCLUSIONS: Given a reported symptomatic response rate of more than 70%, TPE may be a treatment option for individuals with autoimmune-mediated SFN associated with increased titers of TS-HDS IgM autoantibodies. Since TPE-associated adverse events appear common in this population, close monitoring during procedures is warranted.
Subject(s)
Heparitin Sulfate/immunology , Immunoglobulin M , Plasma Exchange , Small Fiber Neuropathy/immunology , Small Fiber Neuropathy/therapy , Adult , Aged , Aged, 80 and over , Disaccharides/immunology , Female , Humans , Male , Middle Aged , Retrospective StudiesABSTRACT
While the improved treatment of human immunodeficiency virus type 1 (HIV-1) infection is available, the development of an effective and safe prophylactic vaccine against HIV-1 is still an unrealized goal. Encouragingly, the discovery of broadly neutralizing antibodies (bNAbs) from HIV-1 positive patients that are capable of neutralizing a broad spectrum of HIV-1 isolates of various clades has accelerated the progress of vaccine development in the past few years. Some of these bNAbs recognize the N-glycans on the viral surface gp120 glycoprotein. We have been interested in using the glycan epitopes recognized by bNAbs for the development of vaccines to elicit bNAb-like antibodies with broadly neutralizing activities. Toward this goal, we have identified novel hybrid-type structures with subnanomolar avidity toward several bNAbs including PG16, PGT121, PGT128-3C, 2G12, VRC13, VRC-PG05, VRC26.25, VRC26.09, PGDM1400, 35O22, and 10-1074. Here, we report the immunogenicity evaluation of a novel hybrid glycan conjugated to carrier DTCRM197, a nontoxic mutant of the diphtheria toxin, for immunization in mice. Our results indicated that the IgG response was mainly against the chitobiose motif with nonspecific binding to a panel of N-glycans with reducing end GlcNAc-GlcNAc (chitobiose) printed on the glass slides. However, the IgM response was mainly toward the reducing end GlcNAc moiety. We further used the glycoconjugates of Man3GlcNAc2, Man5GlcNAc2, and Man9GlcNAc2 glycans for immunization, and a similar specificity pattern was observed. These findings suggest that the immunogenicity of chitobiose may interfere with the outcome of N-glycan-based vaccines, and modification may be necessary to increase the immunogenicity of the entire N-glycan epitope.
Subject(s)
AIDS Vaccines/immunology , Broadly Neutralizing Antibodies/immunology , Glycoconjugates/immunology , HIV Antibodies/immunology , Polysaccharides/immunology , Acetylglucosamine/immunology , Animals , Bacterial Proteins/chemistry , Carbohydrate Sequence , Disaccharides/immunology , Epitopes , Female , Glycoconjugates/chemical synthesis , HIV-1/immunology , Immunoglobulin G/immunology , Immunoglobulin M/immunology , Mice, Inbred C57BL , Polysaccharides/chemical synthesis , Vaccine DevelopmentSubject(s)
Anaphylaxis/chemically induced , Antineoplastic Agents, Immunological/adverse effects , Cetuximab/adverse effects , Disaccharides/immunology , Drug Hypersensitivity/etiology , Immunoglobulin E/blood , Plasma Substitutes/adverse effects , Polygeline/adverse effects , Adult , Anaphylaxis/blood , Anaphylaxis/diagnosis , Anaphylaxis/immunology , Biomarkers/blood , Drug Hypersensitivity/blood , Drug Hypersensitivity/diagnosis , Drug Hypersensitivity/immunology , Epitopes , Humans , Male , Risk FactorsSubject(s)
Anaphylaxis/etiology , Disaccharides/immunology , Food Hypersensitivity/diagnosis , Red Meat/adverse effects , Tick-Borne Diseases/diagnosis , Antibodies/physiology , Diagnosis, Differential , Diarrhea/etiology , Food Hypersensitivity/complications , Humans , Immunoglobulin E/immunology , Middle Aged , Syncope/etiology , Tick-Borne Diseases/complications , Urticaria/etiologyABSTRACT
BACKGROUND: IgE to α-Gal is a cause of mammalian meat allergy and has been linked to tick bites in North America, Australia, and Eurasia. Reports from the developing world indicate that α-Gal sensitization is prevalent but has been little investigated. OBJECTIVE: We sought evidence for the cause(s) of α-Gal sensitization and lack of reported meat allergy among children in less developed settings in Ecuador and Kenya. METHODS: IgE to α-Gal and total IgE were assessed in children from Ecuador (n = 599) and Kenya (n = 254) and compared with children with (n = 42) and without known (n = 63) mammalian meat allergy from the southeastern United States. Information on diet, potential risk factors, and helminth infections was available for children from Ecuador. IgG4 to α-Gal and antibodies to regionally representative parasites were assessed in a subset of children. RESULTS: In Ecuador (32%) and Kenya (54%), α-Gal specific IgE was prevalent, but levels were lower than in children with meat allergy from the United States. Sensitization was associated with rural living, antibody markers of Ascaris exposure, and total IgE, but not active infections with Ascaris or Trichuris species. In Ecuador, 87.5% reported consuming beef at least once per week, including 83.9% of those who had α-Gal specific IgE. Levels of α-Gal specific IgG4 were not high in Ecuador, but were greater than in children from the United States. CONCLUSIONS: These results suggest that in areas of the developing world with endemic parasitism, α-Gal sensitization is (1) common, (2) associated with Ascaris exposure, and (3) distinguished by a low percentage of specific/total IgE compared with individuals with meat allergy in the United States.
Subject(s)
Disaccharides/immunology , Food Hypersensitivity/immunology , Immunoglobulin E/immunology , Immunoglobulin G/immunology , Adolescent , Adult , Animals , Ascaris/immunology , Ascaris/isolation & purification , Child , Child, Preschool , Diet , Ecuador/epidemiology , Feces/parasitology , Female , Food Hypersensitivity/blood , Food Hypersensitivity/epidemiology , Food Hypersensitivity/parasitology , Humans , Immunoglobulin E/blood , Immunoglobulin G/blood , Kenya/epidemiology , Male , Prevalence , Red Meat , Trichuris/isolation & purification , Virginia/epidemiology , Young AdultABSTRACT
BACKGROUND: Human preformed antibodies (Abs), anti-galactose-alpha-1,3-galactose (Gal) and anti-N-glycolylneuraminic acid (Neu5Gc), can react with porcine antigens of wild-type pigs. To provide basic population data of the Abs for potential application in clinical xenotransplantation, we developed enzyme-linked immunosorbent assay methods and investigated the serum titers of anti-Gal and anti-Neu5Gc Abs, including immunoglobulin (Ig) M and IgG along with its subclasses, in humans. METHODS: Anti-Gal and anti-Neu5Gc Abs serum titers were measured in 380 healthy Korean adults using the in-house enzyme-linked immunosorbent assays. The frequency and median values of anti-Gal and anti-Neu5Gc were measured, and their class and subclass distribution were evaluated. RESULTS: The detection frequencies of anti-Gal were 99.2%, 95.0%, 23.2%, 94.5%, 12.4%, and 3.4% for IgM, IgG, IgG1, IgG2, IgG3, and IgG4, respectively. The detection frequencies of anti-Neu5Gc Abs were 87.4%, 96.6%, 1.6%, 46.3%, 0.0%, and 0.0% for IgM, IgG, IgG1, IgG2, IgG3, and IgG4, respectively. The median values of anti-Gal IgM (1001.6 ng/mL) and IgG (1198.3 ng/mL) were significantly higher than those of anti-Neu5Gc Abs (IgM, 328.4 ng/mL; IgG, 194.7 ng/mL; P < .001). IgG2 titers of both anti-Gal and anti-Neu5Gc Abs correlated better with the IgG class than the titers of other IgG subclasses. CONCLUSIONS: The titers of anti-Gal Abs were higher than those of anti-Neu5Gc Abs. IgG2 was the main IgG subclass in both anti-Gal and anti-Neu5Gc Abs. Variation in the titers of anti-Gal or anti-Neu5Gc Abs may partly explain the biological and immunologic changes that occur in recipients of xenotransplants.
Subject(s)
Disaccharides/immunology , Immunoglobulin G/blood , Immunoglobulin M/blood , Neuraminic Acids/immunology , Adult , Animals , Endothelium, Vascular/cytology , Endothelium, Vascular/immunology , Endothelium, Vascular/metabolism , Enzyme-Linked Immunosorbent Assay , Female , Humans , Immunoglobulin G/classification , Immunoglobulin G/immunology , Immunoglobulin M/immunology , Male , Middle Aged , SwineABSTRACT
The coronavirus disease 2019 (COVID-19) pandemic caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has affected millions of people worldwide. Characterization of the immunological mechanisms involved in disease symptomatology and protective response is important to progress in disease control and prevention. Humans evolved by losing the capacity to synthesize the glycan Galα1-3Galß1-(3)4GlcNAc-R (α-Gal), which resulted in the development of a protective response against pathogenic viruses and other microorganisms containing this modification on membrane proteins mediated by anti-α-Gal immunoglobulin M (IgM)/IgG antibodies produced in response to bacterial microbiota. In addition to anti-α-Gal antibody-mediated pathogen opsonization, this glycan induces various immune mechanisms that have shown protection in animal models against infectious diseases without inflammatory responses. In this study, we hypothesized that the immune response to α-Gal may contribute to the control of COVID-19. To address this hypothesis, we characterized the antibody response to α-Gal in patients at different stages of COVID-19 and in comparison with healthy control individuals. The results showed that while the inflammatory response and the anti-SARS-CoV-2 (Spike) IgG antibody titers increased, reduction in anti-α-Gal IgE, IgM, and IgG antibody titers and alteration of anti-α-Gal antibody isotype composition correlated with COVID-19 severity. The results suggested that the inhibition of the α-Gal-induced immune response may translate into more aggressive viremia and severe disease inflammatory symptoms. These results support the proposal of developing interventions such as probiotics based on commensal bacteria with α-Gal epitopes to modify the microbiota and increase α-Gal-induced protective immune response and reduce severity of COVID-19.
Subject(s)
Antibodies, Viral/analysis , COVID-19/immunology , Disaccharides/immunology , Immunity, Humoral , Aged , Aged, 80 and over , Antibodies, Bacterial/analysis , COVID-19/diagnosis , Epitopes/immunology , Female , Humans , Immunoglobulin G/analysis , Male , Microbiota/immunology , Middle Aged , Severity of Illness Index , SpainABSTRACT
The level of human natural antibodies of immunoglobulin M isotype against LeC in patients with breast cancer is lower than in healthy women. The epitope specificity of these antibodies has been characterized using a printed glycan array and enzyme-linked immunosorbent assay (ELISA), the antibodies being isolated from donors' blood using LeC-Sepharose (LeC is Galß1-3GlcNAcß). The isolated antibodies recognize the disaccharide but do not bind to glycans terminated with LeC, which implies the impossibility of binding to regular glycoproteins of non-malignant cells. The avidity (as dissociation constant value) of antibodies probed with a multivalent disaccharide is 10-9 M; the nanomolar level indicates that the concentration is sufficient for physiological binding to the cognate antigen. Testing of several breast cancer cell lines showed the strongest binding to ZR 75-1. Interestingly, only 7% of the cells were positive in a monolayer with a low density, increasing up to 96% at highest density. The enhanced interaction (instead of the expected inhibition) of antibodies with ZR 75-1 cells in the presence of Galß1-3GlcNAcß disaccharide, indicates that the target epitope of anti-LeC antibodies is a molecular pattern with a carbohydrate constituent rather than a glycan.
Subject(s)
Disaccharides/immunology , Epitopes/immunology , Galactans/immunology , Animals , Antibodies/immunology , Antibodies/metabolism , Breast Neoplasms/immunology , Cell Line, Tumor , Disaccharides/chemistry , Disaccharides/metabolism , Enzyme-Linked Immunosorbent Assay , Female , Galactans/metabolism , Humans , Immunoglobulin M/immunology , Mice , Mice, Knockout , Polysaccharides/chemistry , Polysaccharides/immunology , Polysaccharides/metabolism , Protein BindingABSTRACT
BACKGROUND: Alpha-gal is an oligosaccharide implicated in delayed anaphylaxis following red meat consumption. Exposure to tick bites has been correlated with development of an allergic response to alpha-gal. However, evidence prospectively linking exposure to a single tick species and an immune response to alpha-gal is lacking. METHODS: We used serum samples from a prior study cohort of outdoor workers in North Carolina, USA, with high exposure to the lone star tick, Amblyomma americanum, to prospectively evaluate the relationship between tick bites and anti-alpha-gal IgE antibodies. RESULTS: Individuals who reported exposure to one or more tick bites were significantly more likely to have a positive change in anti-alpha-gal IgE compared to individuals with no reported tick bites. This relationship was not dependent on time. A trend toward increasing number of tick bites and increased anti-alpha-gal IgE levels was observed but not statistically significant. CONCLUSION: To our knowledge, this is the first study to prospectively link documented exposure to A. americanum bites and increased sensitization to alpha-gal in a cohort of outdoor workers. Our results support the role of A. americanum as likely agents for eliciting an allergic response to red meat, and highlight the importance of preventing tick bites.
Subject(s)
Amblyomma/physiology , Food Hypersensitivity/etiology , Food Hypersensitivity/immunology , Red Meat/adverse effects , Tick Bites/complications , Adult , Amblyomma/immunology , Animals , Cattle , Disaccharides/immunology , Farmers , Female , Food Hypersensitivity/blood , Humans , Immunoglobulin E/blood , Immunoglobulin E/immunology , Male , Middle Aged , North Carolina , Prospective Studies , Tick Bites/immunology , Tick Bites/parasitologyABSTRACT
PURPOSE OF REVIEW: Functional dyspepsia (FD) is a chronic functional gastrointestinal disorder characterised by upper gastrointestinal symptoms. Here, we aimed to examine the evidence for immune responses to food in FD and overlap with food hypersensitivity conditions. RECENT FINDINGS: A feature of FD in a subset of patients is an increase in mucosal eosinophils, mast cells, intraepithelial cytotoxic T cells and systemic gut-homing T cells in the duodenum, suggesting that immune dysfunction is characteristic of this disease. Rates of self-reported non-celiac wheat/gluten sensitivity (NCW/GS) are higher in FD patients. FD patients commonly report worsening symptoms following consumption of wheat, fermentable oligosaccharides, disaccharides, monosaccharides, or polyols (FODMAPs), high-fat foods and spicy foods containing capsaicin. Particularly, wheat proteins and fructan in wheat may drive symptoms. Immune mechanisms that drive responses to food in FD are still poorly characterised but share key effector cells to common food hypersensitivities including non-IgE-mediated food allergy and eosinophilic oesophagitis.