Subject(s)
Allergens , Arachis , Disease Models, Animal , Galactose , Mannans , Peanut Hypersensitivity , Animals , Peanut Hypersensitivity/immunology , Peanut Hypersensitivity/therapy , Mice , Galactose/immunology , Galactose/analogs & derivatives , Mannans/immunology , Arachis/immunology , Allergens/immunology , Immunoglobulin E/immunology , Desensitization, Immunologic/methods , Humans , Mice, Inbred BALB C , FemaleABSTRACT
Invertebrate lectins exhibit structural diversity and play crucial roles in the innate immune responses by recognizing and eliminating pathogens. In the present study, a novel lectin containing a Gal_Lectin, a CUB and a transmembrane domain was identified from the Pacific oyster Crassostrea gigas (defined as CgGal-CUB). CgGal-CUB mRNA was detectable in all the examined tissues with the highest expression in adductor muscle (11.00-fold of that in haemocytes, p < 0.05). The expression level of CgGal-CUB mRNA in haemocytes was significantly up-regulated at 3, 24, 48 and 72 h (8.37-fold, 12.13-fold, 4.28-fold and 10.14-fold of that in the control group, respectively) after Vibrio splendidus stimulation. The recombinant CgGal-CUB (rCgGal-CUB) displayed binding capability to Mannan (MAN), peptidoglycan (PGN), D-(+)-Galactose and L-Rhamnose monohydrate, as well as Gram-negative bacteria (Escherichia coli, V. splendidus and Vibrio anguillarum), Gram-positive bacteria (Micrococcus luteus, Staphylococcus aureus, and Bacillus sybtilis) and fungus (Pichia pastoris). rCgGal-CUB was also able to agglutinate V. splendidus, and inhibit V. splendidus growth. Furthermore, rCgGal-CUB exhibited the activities of enhancing the haemocyte phagocytosis towards V. splendidus, and the phagocytosis rate of haemocytes was descended in blockage assay with CgGal-CUB antibody. These results suggested that CgGal-CUB served as a pattern recognition receptor to bind various PAMPs and bacteria, and enhanced the haemocyte phagocytosis towards V. splendidus.
Subject(s)
Crassostrea , Hemocytes , Immunity, Innate , Lectins , Phagocytosis , Vibrio , Animals , Hemocytes/immunology , Hemocytes/metabolism , Crassostrea/immunology , Vibrio/immunology , Vibrio/physiology , Lectins/metabolism , Lectins/genetics , Lectins/immunology , Mannans/metabolism , Mannans/immunology , Protein Domains/genetics , Peptidoglycan/immunology , Peptidoglycan/metabolism , Galactose/metabolism , Galactose/immunology , Vibrio Infections/immunologyABSTRACT
Vaccines represent a pivotal health advancement for preventing infection. However, because carrier systems with repeated administration can invoke carrier-targeted immune responses that diminish subsequent immune responses (e.g., PEG antibodies), there is a continual need to develop novel vaccine platforms. Zinc carnosine microparticles (ZnCar MPs), which are composed of a one-dimensional coordination polymer formed between carnosine and the metal ion zinc, have exhibited efficacy in inducing an immune response against influenza. However, ZnCar MPs' limited suspendability hinders clinical application. In this study, we address this issue by mixing mannan, a polysaccharide derived from yeast, with ZnCar MPs. We show that the addition of mannan increases the suspendability of this promising vaccine formulation. Additionally, since mannan is an adjuvant, we illustrate that the addition of mannan increases the antibody response and T cell response when mixed with ZnCar MPs. Mice vaccinated with mannan + OVA/ZnCar MPs had elevated serum IgG and IgG1 levels in comparison to vaccination without mannan. Moreover, in the mannan + OVA/ZnCar MPs vaccinated group, mucosal washes demonstrated increased IgG, IgG1, and IgG2c titers, and antigen recall assays showed enhanced IFN-γ production in response to MHC-I and MHC-II immunodominant peptide restimulation, compared to the vaccination without mannan. These findings suggest that the use of mannan mixed with ZnCar MPs holds potential for subunit vaccination and its improved suspendability further promotes clinical translation.
Subject(s)
Carnosine , Mannans , Vaccines, Subunit , Zinc , Mannans/chemistry , Mannans/administration & dosage , Mannans/immunology , Animals , Vaccines, Subunit/administration & dosage , Vaccines, Subunit/immunology , Zinc/chemistry , Zinc/administration & dosage , Carnosine/administration & dosage , Carnosine/chemistry , Female , Immunoglobulin G/blood , Mice , Adjuvants, Immunologic/administration & dosage , Adjuvants, Immunologic/chemistry , Ovalbumin/immunology , Ovalbumin/administration & dosage , Mice, Inbred C57BL , Polymers/chemistry , Polymers/administration & dosage , Mice, Inbred BALB C , Drug Carriers/chemistryABSTRACT
INTRODUCTION: IgE-mediated peanut allergy is an important public health problem of increasing prevalence leading to anaphylactic reactions both in children and adults. Allergen-specific oral immunotherapy (OIT) is the single treatment with the potential capacity to modify the course of the disease, but it still faces some drawbacks in terms of efficacy, safety, patients' adherence, and cost. Alternative strategies, including the use of novel adjuvants, to overcome such limitations are highly demanded. The main aim of this study was to search for potential novel adjuvants for peanut OIT by assessing the capacity of free purified mannan and different toll-like receptor ligands (TLR-Ls) to immunomodulate the responses of human monocyte-derived dendritic cells (hmoDCs) to peanut allergens. METHODS: Monocytes were isolated from PBMCs of healthy donors and differentiated into hmoDCs. Flow cytometry, ELISA, coculture, and suppression assay were performed to assess the effects of TLR-Ls, mannan, and crude peanut extract (CPE) in hmoDCs. RESULTS: Purified free mannan increased the expression levels of HLA-DR, CD86, CD83, and PD-L1 and induced a higher IL-10/IL-6 cytokine ratio in hmoDCs compared to the stimulation with different TLR-Ls. Mannan significantly increased the expression of HLA-DR, the maturation marker CD83, the tolerogenic marker PD-L1, as well as the production of IL-10, IL-6, and TNF-α in CPE-stimulated hmoDCs. Supporting these tolerogenic properties, mannan also significantly increased the frequency of FOXP3+ regulatory T cells generated by CPE-treated hmoDCs with functional suppressive capacity. CONCLUSIONS: We uncover that purified free mannan induces tolerogenic responses in human DCs stimulated with peanut allergens, suggesting mannan as a suitable potential novel adjuvant to be exploited in the context of OIT for peanut allergy.
Subject(s)
Allergens , Arachis , Dendritic Cells , Immune Tolerance , Mannans , Peanut Hypersensitivity , Humans , Dendritic Cells/immunology , Mannans/immunology , Mannans/pharmacology , Arachis/immunology , Peanut Hypersensitivity/immunology , Allergens/immunology , Cytokines/metabolism , Desensitization, Immunologic/methods , Cells, Cultured , Toll-Like Receptors/metabolism , Toll-Like Receptors/immunology , Adjuvants, ImmunologicABSTRACT
Activation of the innate immune system via pattern recognition receptors (PRRs) is key to generate lasting adaptive immunity. PRRs detect unique chemical patterns associated with invading microorganisms, but whether and how the physical properties of PRR ligands influence the development of the immune response remains unknown. Through the study of fungal mannans, we show that the physical form of PRR ligands dictates the immune response. Soluble mannans are immunosilent in the periphery but elicit a potent pro-inflammatory response in the draining lymph node (dLN). By modulating the physical form of mannans, we developed a formulation that targets both the periphery and the dLN. When combined with viral glycoprotein antigens, this mannan formulation broadens epitope recognition, elicits potent antigen-specific neutralizing antibodies, and confers protection against viral infections of the lung. Thus, the physical properties of microbial ligands determine the outcome of the immune response and can be harnessed for vaccine development.
Subject(s)
Adjuvants, Immunologic/pharmacology , Antigens, Viral/immunology , Candida albicans/chemistry , Mannans/immunology , Aluminum Hydroxide/chemistry , Animals , Antibodies, Neutralizing/immunology , Antibody Specificity/immunology , B-Lymphocytes/immunology , COVID-19/immunology , COVID-19/prevention & control , COVID-19/virology , Chlorocebus aethiops , Epitopes/immunology , Immunity, Innate , Immunization , Inflammation/pathology , Interferons/metabolism , Lectins, C-Type/metabolism , Ligands , Lung/immunology , Lung/pathology , Lung/virology , Lymph Nodes/immunology , Lymph Nodes/metabolism , Macrophages/metabolism , Mice, Inbred C57BL , Paranasal Sinuses/metabolism , Protein Subunits/metabolism , Sialic Acid Binding Ig-like Lectin 1/metabolism , Solubility , Spike Glycoprotein, Coronavirus/metabolism , T-Lymphocytes/immunology , Transcription Factor RelB/metabolism , Vero Cells , beta-Glucans/metabolismABSTRACT
OBJECTIVE: Studies have confirmed that real-time PCR detection of Aspergillus DNA in bronchoalveolar lavage fluid (BALF) is more valuable than blood samples in the diagnosis of invasive pulmonary aspergillosis (IPA). The latest guidelines recommend the use of serum samples for Aspergillus antibody testing for chronic pulmonary aspergillosis (CPA). However, research on CPA diagnosed by real-time PCR testing of BALF has been limited. In this study, we assessed the clinical value of BALF GM and PCR detection in diagnosing CPA. METHODS: The diagnostic criteria of this study were based on the 2015 ESCMID/ERS guidelines for CPA. Seventy-nine patients with CPA and 74 non-CPA patients were enrolled. Aspergillus DNA in BALF was detected in the patients with CPA. RESULTS: The sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and area under the curve (AUC) of BALF PCR in the CPA group were 87.18%, 89.80%, 87.18%, 89.80%, and 0.89 (95% CI 0.82-0.95), respectively (P<0.005). The sensitivity, specificity, PPV, and NPV of BALF Aspergillus galactomannan (GM) detection in the CPA group were 66.67%, 89.80%, 83.87%, and 77.19%, respectively, and the AUC was 0.94 (95% CI 0.89-0.99) (P<0.005). When combining BALF GM and BALF PCR detection, the sensitivity, specificity, PPV, and NPV were 92.31%, 89.80%, 87.80%, and 93.62%, respectively. CONCLUSION: The BALF PCR detection method has good diagnostic value for CPA and combining this method with BALF GM detection can improve diagnostic sensitivity and specificity.
Subject(s)
Bronchoalveolar Lavage Fluid/microbiology , DNA, Bacterial/analysis , Pulmonary Aspergillosis/diagnosis , Real-Time Polymerase Chain Reaction/methods , Adult , Aged , Antigens, Bacterial/analysis , Antigens, Bacterial/immunology , Aspergillus/genetics , Aspergillus/immunology , Chronic Disease , Early Diagnosis , Female , Galactose/analogs & derivatives , Galactose/immunology , Humans , Male , Mannans/immunology , Middle Aged , Predictive Value of Tests , Prospective Studies , Pulmonary Aspergillosis/diagnostic imaging , Sensitivity and SpecificityABSTRACT
BACKGROUND: The efficacy of allergen-specific immunotherapy (AIT) is mainly depended on the tolerogenic immune responses elicited. Properly conjugated nano-vaccine has the advantages of both specific targeting and continuous and on-demand release of allergen. OBJECTIVES: The aim of this study is to investigate the effects of a dendritic cells (DCs)-targeting nano-vaccine for AIT. METHODS: The nano-vaccine was produced by coupling polylactic-co-glycolic acid (PLGA)-encapsulated ovalbumin (OVA) with mannan. Allergen capture, human monocytes-derived DCs (hMoDCs) activation, and T cells responses were assessed by flow cytometry, confocal microscopy, quantitative real-time PCR, ELISA, and Cytometric Bead Array. Balb/c mice were immunized with the nano-vaccines, and the immune responses were analyzed. RESULTS: OVA-PLGA nanoparticle (NP) displayed favorable safety profile. OVA-mannan-PLGA NP was captured more efficiently by hMoDCs than OVA-PLGA NP, which was mediated mainly through DC-specific intercellular adhesion molecule 3-grabbing nonintegrin. A tolerogenic phenotype of hMoDCs was induced by OVA-mannan-PLGA NP, but not OVA-PLGA NP, and increased number of regulatory T (Treg) cells was generated subsequently in in vitro coculture. Immunization of Balb/c mice with OVA-mannan-PLGA NP resulted in lower serum level of OVA-specific immunoglobulins and less production of pro-inflammatory cytokines in splenocytes culture than the mice immunized with OVA-PLAG NP, PLGA NP, or OVA, while the number of splenic Treg cells was higher in OVA-mannan-PLGA group than in other groups. Moreover, preimmunization with OVA-mannan-PLGA NP significantly inhibited the Th2 immune response induced by OVA sensitization. CONCLUSIONS: The biocompatible PLGA-encapsulated OVA coupling with mannan has augmented ability for tolerance induction and could be developed as a novel vaccine for AIT.
Subject(s)
Allergens/immunology , Dendritic Cells/immunology , Mannans/immunology , Nanoparticles , Polylactic Acid-Polyglycolic Acid Copolymer , T-Lymphocytes, Regulatory/immunology , Vaccines/immunology , Allergens/administration & dosage , Animals , Desensitization, Immunologic , Hypersensitivity/immunology , Hypersensitivity/therapy , Immune Tolerance , Immunization , Mice , T-Lymphocytes, Regulatory/metabolismABSTRACT
Introduction: Adjuvants are essential to vaccines for immunopotentiation in the elicitation of protective immunity. However, classical and widely used aluminum-based adjuvants have limited capacity to induce cellular response. There are increasing needs for appropriate adjuvants with improved profiles for vaccine development toward emerging pathogens. Carbohydrate-containing nanoparticles (NPs) with immunomodulatory activity and particulate nanocarriers for effective antigen presentation are capable of eliciting a more balanced humoral and cellular immune response.Areas covered: We reviewed several carbohydrates with immunomodulatory properties. They include chitosan, ß-glucan, mannan, and saponins, which have been used in vaccine formulations. The mode of action, the preparation methods, characterization of these carbohydrate-containing NPs and the corresponding vaccines are presented.Expert opinion: Several carbohydrate-containing NPs have entered the clinical stage or have been used in licensed vaccines for human use. Saponin-containing NPs are being evaluated in a vaccine against SARS-CoV-2, the pathogen causing the on-going worldwide pandemic. Vaccines with carbohydrate-containing NPs are in different stages of development, from preclinical studies to late-stage clinical trials. A better understanding of the mode of action for carbohydrate-containing NPs as vaccine carriers and as immunostimulators will likely contribute to the design and development of new generation vaccines against cancer and infectious diseases.
Subject(s)
Adjuvants, Immunologic/chemistry , COVID-19 Vaccines/chemistry , COVID-19/prevention & control , Carbohydrates/chemistry , Nanoparticles/chemistry , Adjuvants, Immunologic/administration & dosage , Animals , COVID-19/immunology , COVID-19 Vaccines/administration & dosage , COVID-19 Vaccines/immunology , Carbohydrates/administration & dosage , Carbohydrates/immunology , Chitosan/administration & dosage , Chitosan/chemistry , Chitosan/immunology , Humans , Mannans/administration & dosage , Mannans/chemistry , Mannans/immunology , Nanoparticles/administration & dosage , beta-Glucans/administration & dosage , beta-Glucans/chemistry , beta-Glucans/immunologyABSTRACT
Candida albicans mannan consists of a large repertoire of oligomannosides with different types of mannose linkages and chain lengths, which act as individual epitopes with more or less overlapping antibody specificities. Although anti-C. albicans mannan antibody levels are monitored for diagnostic purposes nothing is known about the qualitative distribution of these antibodies in terms of epitope specificity. We addressed this question using a bank of previously synthesized biotin sulfone tagged oligomannosides (BSTOs) of α and ß anomery complemented with a synthetic ß-mannotriose described as a protective epitope. The reactivity of these BSTOs was analyzed with IgM isotype monoclonal antibodies (MAbs) of known specificity, polyclonal sera from patients colonized or infected with C. albicans, and mannose binding lectin (MBL). Surface plasmon resonance (SPR) and multiple analyte profiling (MAP) were used. Both methods confirmed the usual reactivity of MAbs against either α or ß linkages, excepted for MAb B6.1 (protective epitope) reacting with ß-Man whereas the corresponding BSTO reacted with anti-α-Man. These results were confirmed in western blots with native C. albicans antigens. Using patients' sera in MAP, a significant correlation was observed between the detection of anti-mannan antibodies recognizing ß- and α-Man epitopes and detection of antibodies against ß-linked mannotriose suggesting that this epitope also reacts with human polyclonal antibodies of both specificities. By contrast, the reactivity of human sera with other α- and ß-linked BSTOs clearly differed according to their colonized or infected status. In these cases, the establishment of an α/ß ratio was extremely discriminant. Finally SPR with MBL, an important lectin of innate immunity to C. albicans, classically known to interact with α-mannose, also interacted in an unexpected way with the protective epitope. These cumulative data suggest that structure/activity investigations of the finely tuned C. albicans anti-mannose immune response are worthwhile to increase our basic knowledge and for translation in medicine.
Subject(s)
Antibodies, Monoclonal/blood , Candida albicans/immunology , Candidiasis/immunology , Mannans/immunology , Antibody Specificity , Antigens, Fungal/blood , Candidiasis/blood , Epitope Mapping , Mannans/chemistry , Oligosaccharides/analysis , Surface Plasmon Resonance , Trisaccharides/chemistry , Trisaccharides/immunologyABSTRACT
BACKGROUND: Aspergillus species meet the most important group of invasive fungal diseases (IFD) in immunosuppressed patients. Galactomannan is a polysaccharide antigen located in the wall structure of Aspergillus. The most commonly used method for antigen detection is enzyme-linked immunoassay (ELISA). Aspergillus galactomannan lateral flow assay (LFA) constitutes one of the new methods in the diagnosis of invasive aspergillosis (IA). The goal of this study was to demonstrate efficacy of LFA in our patients and to compare it to synchronous ELISA results. METHODS: Galactomannan antigen was examined using both LFA and ELISA in serum samples taken from patients who were followed up in our haematology clinic. All patients are classified in subgroups as 'proven', 'probable' and 'possible' patients according to the last EORTC / MSG guideline. Patients who met the 'proven' IA criteria were included in the study as the gold standard. RESULTS: A total of 87 patients were included in the study. Majority of patients had acute myeloid leukaemia (AML) (56.3%). Eleven (12.6%) were in 'proven' IA group. LFA test showed a superior diagnostic performance compared with ELISA (LFAAUC = 0.934 vs ELISAAUC = 0.545; p < .001). The LFA had a sensitivity of 90.9% and a specificity of 90.8% for '0.5 ODI' in predicting IA (PPV = 55.8%; NPV = 98.6%; p < .001). CONCLUSION: The most important finding of this study is that the specificity of LFA was found to be higher for cut-off value of 0.5. It is recommended to combine the methods in many studies to provide a better early diagnosis for IA.
Subject(s)
Aspergillosis/diagnosis , Aspergillus , Mannans/blood , Adult , Aged , Aged, 80 and over , Antigens, Fungal/analysis , Antigens, Fungal/blood , Antigens, Fungal/immunology , Aspergillus/immunology , Aspergillus/isolation & purification , Bronchoalveolar Lavage Fluid/microbiology , Diagnostic Tests, Routine/methods , Enzyme-Linked Immunosorbent Assay , Female , Galactose/analogs & derivatives , Humans , Immunocompromised Host , Invasive Fungal Infections/diagnosis , Leukemia, Myeloid/complications , Male , Mannans/analysis , Mannans/immunology , Middle Aged , Sensitivity and SpecificityABSTRACT
A basis for the genetic predisposition to psoriasis is a single locus, PSORS1, within the major histocompatibility complex I region. This murine major histocompatibility complex locus encodes nonclassical molecules such as Qa2. We hypothesized that a natural loss-of-function variant of Qa2 gene clusters promotes psoriasis. In this study, we have developed a mannan-induced psoriasis model with the double deficiency of Qa2 and ROS owing to natural mutations of Qa2 gene clusters and the Ncf1 gene in the C57BL/6 background, respectively. We report three key findings in mice with mannan-induced psoriasis. A complete deficiency of Qa2 resulted in the expansion of IL-17âproducing γδ T cells and group 3 innate lymphoid cells in draining lymph nodes, leading to ear psoriasis. A single copy of Qa2-encoding genes was enough to protect against mannan-induced psoriasis, and such a protection was erased by a mutated Ncf1. Double defects with Qa2 and Ncf1 elicited a spread of exaggerated ear psoriasis to the nails, and the deficiency of γδ T cells reduced the severity of nail psoriasis. Collectively, these findings in mice provide evidence for the importance of Ncf1 mutations and Qa2 gene clusters, possibly corresponding to the PSORS1 locus in the spread of psoriasis.
Subject(s)
Genetic Predisposition to Disease , Histocompatibility Antigens Class I/genetics , NADPH Oxidases/genetics , Psoriasis/genetics , Animals , Disease Models, Animal , Humans , Immunity, Innate/genetics , Interleukin-17/metabolism , Intraepithelial Lymphocytes/immunology , Intraepithelial Lymphocytes/metabolism , Loss of Function Mutation , Male , Mannans/administration & dosage , Mannans/immunology , Mice , Multigene Family , Psoriasis/immunologyABSTRACT
A commercial Aspergillus galactomannan antigen (GMA) enzyme linked immunosorbent assay (ELISA) is used to support a diagnosis of systemic aspergillosis in dogs. In human patients, false positive results have been associated with administration of medications derived from molds. We sought to determine the effect of administration of a commercially available oral probiotic nutraceutical that contained Aspergillus-derived ingredients on serum and urine Aspergillus GMA levels in dogs by conducting a prospective, cross-over study. Galactomannan index (GMI) was measured on the solubilized probiotic nutraceutical and was positive (GMI ≥ 0.5) with a mean of 7.91. Serum and urine galactomannan indices were measured in 10 healthy dogs before (day 0) and after 1 week (day 7) of probiotic nutraceutical administration, then again 2 weeks after the probiotic nutraceutical was discontinued (day 21). Median (range) serum GMI were 0.19 (0.08-0.62), 0.22 (0.07-1.15) and 0.17 (0.14-0.63) at day 0, 7 and 21, respectively. Two of 10 dogs developed positive GMI (≥0.5) results after probiotic nutraceutical administration; however, no significant changes were noted over the study period. Median (range) urine GMI results were 0.06 (0.04-0.22), 0.07 (0.05-0.41) and 0.06 (0.03-0.16) at day 0, 7 and 21, respectively. A trend towards an increase urine GMI was noted between day 0 and 7 (P = 0.18), and decrease was noted between day 7 and 21 (P = 0.09). Administration of probiotics containing Aspergillus-derived ingredients to dogs did not reliably result in elevated Aspergillus GMA levels.
Subject(s)
Antigens, Fungal/analysis , Aspergillosis/veterinary , Aspergillus/immunology , Dog Diseases/microbiology , Mannans/immunology , Probiotics/administration & dosage , Animals , Antigens, Fungal/blood , Antigens, Fungal/urine , Aspergillosis/diagnosis , Dietary Supplements/microbiology , Dog Diseases/diagnosis , Dogs , Enzyme-Linked Immunosorbent Assay/veterinary , Female , Galactose/analogs & derivatives , MaleABSTRACT
Oropharyngeal candidiasis is the most common opportunistic fungal infectious disease. Culture methods and microscopy are used to detect the presence of Candida species in clinical specimens. We have previously developed an immunochromatographic test (ICT) to enable the simple and rapid diagnosis of candidiasis. In this study, we evaluated the performance of the ICT for the detection of Candida species from pharyngeal swabs and compared the results with those of the culture method. The isolated Candida species were identified using polymerase chain reaction-restriction fragment length polymorphism, and viable cell counts were determined using selective chromogenic agar. The detection rate of C. albicans was 63.3% and 0% among ≤102 and ≥ 106 colony-forming units (CFU)/mL of viable Candida cells from pharyngeal swabs, respectively. The detection rate of nonC. albicans Candida species, especially C. glabrata, increased commensurately from 16.7% at ≤102 CFU/mL to 75.0% at ≥106 CFU/mL. Among the 300 pharyngeal swabs analyzed, 59 cultures detected Candida species at a count of >103 CFU/mL (53 were ICT-positive). Of the remaining 241 culture-negative specimens, 219 were ICT-negative. The sensitivity, specificity, and accuracy of the ICT were 89.8%, 90.9%, and 90.7%, respectively. Taken together, the ICT evaluated can be made readily available for clinical use in detecting Candida.
Subject(s)
Candida/classification , Candida/immunology , Candidiasis/diagnosis , Immunoassay/methods , Pharynx/microbiology , Candida/genetics , Candida/isolation & purification , Candidiasis/microbiology , DNA, Fungal/genetics , Humans , Immunoglobulin G/immunology , Mannans/immunology , Polymerase Chain Reaction , Polymorphism, Restriction Fragment LengthSubject(s)
Allergens/immunology , Galactans/immunology , Mannans/immunology , Occupational Diseases/diagnosis , Occupational Diseases/etiology , Plant Gums/immunology , Rhinitis/diagnosis , Rhinitis/etiology , Biomarkers , Cross Reactions/immunology , Fabaceae/immunology , Humans , Immunization , Immunoglobulin E/blood , Immunoglobulin E/immunology , Inhalation Exposure , Nuts/immunology , Skin TestsABSTRACT
Even though both cellular and humoral immunities contribute to host defense, the role played by humoral immunity against the airborne opportunistic fungal pathogen Aspergillus fumigatus has been underexplored. In this study, we aimed at deciphering the role of the complement system, the major humoral immune component, against A. fumigatus Mass spectrometry analysis of the proteins extracted from A. fumigatus conidial (asexual spores and infective propagules) surfaces opsonized with human serum indicated that C3 is the major complement protein involved. Flow cytometry and immunolabeling assays further confirmed C3b (activated C3) deposition on the conidial surfaces. Assays using cell wall components of conidia indicated that the hydrophobin RodAp, ß-(1,3)-glucan (BG) and galactomannan (GM) could efficiently activate C3. Using complement component-depleted sera, we showed that while RodAp activates C3 by the alternative pathway, BG and GM partially follow the classical and lectin pathways, respectively. Opsonization facilitated conidial aggregation and phagocytosis, and complement receptor (CR3 and CR4) blockage on phagocytes significantly inhibited phagocytosis, indicating that the complement system exerts a protective role against conidia by opsonizing them and facilitating their phagocytosis mainly through complement receptors. Conidial opsonization with human bronchoalveolar lavage fluid (BALF) confirmed C3 to be the major complement protein interacting with conidia. Nevertheless, complement C2 and mannose-binding lectin (MBL), the classical and lectin pathway components, respectively, were not identified, indicating that BALF activates the alternative pathway on the conidial surface. Moreover, the cytokine profiles were different upon stimulation of phagocytes with serum- and BALF-opsonized conidia, highlighting the importance of studying interaction of conidia with complement proteins in their biological niche.
Subject(s)
Aspergillus fumigatus/immunology , Bronchoalveolar Lavage Fluid/immunology , Complement C3/immunology , Fungal Polysaccharides/pharmacology , Macrophages/drug effects , Serum/immunology , Spores, Fungal/immunology , Aspergillosis/genetics , Aspergillosis/immunology , Aspergillosis/microbiology , Aspergillus fumigatus/chemistry , Bronchoalveolar Lavage Fluid/chemistry , Bronchoalveolar Lavage Fluid/microbiology , Cell Wall/chemistry , Cell Wall/immunology , Complement Activation/drug effects , Complement C3/genetics , Cytokines/biosynthesis , Cytokines/immunology , Fungal Polysaccharides/immunology , Fungal Polysaccharides/isolation & purification , Galactose/analogs & derivatives , Host Microbial Interactions/immunology , Humans , Immunity, Cellular , Immunity, Humoral , Integrin alphaXbeta2/genetics , Integrin alphaXbeta2/immunology , Macrophage-1 Antigen/genetics , Macrophage-1 Antigen/immunology , Macrophages/immunology , Macrophages/microbiology , Mannans/immunology , Mannans/isolation & purification , Mannans/pharmacology , Opsonin Proteins/pharmacology , Phagocytosis/drug effects , Primary Cell Culture , Protein Binding , Reactive Oxygen Species , Serum/chemistry , Serum/microbiology , Spores, Fungal/chemistry , beta-Glucans/immunology , beta-Glucans/isolation & purification , beta-Glucans/pharmacologySubject(s)
Allergens/immunology , Down Syndrome/diagnosis , Galactans/immunology , Leukocyte L1 Antigen Complex/immunology , Mannans/immunology , Milk Hypersensitivity/diagnosis , Plant Gums/immunology , Administration, Oral , Diarrhea , Enterocolitis , Humans , Immunization , Infant , Lethargy , Male , Syndrome , VomitingABSTRACT
A better understanding of all immune components involved in protecting against Mycobacterium tuberculosis infection is urgently needed to inform strategies for novel immunotherapy and tuberculosis (TB) vaccine development. Although cell-mediated immunity is critical, increasing evidence supports that antibodies also have a protective role against TB. Yet knowledge of protective antigens is limited. Analyzing sera from 97 US immigrants at various stages of M. tuberculosis infection, we showed protective in vitro and in vivo efficacy of polyclonal IgG against the M. tuberculosis capsular polysaccharide arabinomannan (AM). Using recently developed glycan arrays, we established that anti-AM IgG induced in natural infection is highly heterogeneous in its binding specificity and differs in both its reactivity to oligosaccharide motifs within AM and its functions in bacillus Calmette-Guérin vaccination and/or in controlled (latent) versus uncontrolled (TB) M. tuberculosis infection. We showed that anti-AM IgG from asymptomatic but not from diseased individuals was protective and provided data suggesting a potential role of IgG2 and specific AM oligosaccharides. Filling a gap in the current knowledge of protective antigens in humans, our data support the key role of the M. tuberculosis surface glycan AM and suggest the importance of targeting specific glycan epitopes within AM in antibody-mediated immunity against TB.
Subject(s)
Antibodies, Bacterial/immunology , BCG Vaccine/immunology , Immunoglobulin G/immunology , Mannans/immunology , Mycobacterium tuberculosis/immunology , Oligosaccharides/immunology , Tuberculosis/immunology , Animals , Female , Humans , Male , Mice , THP-1 CellsABSTRACT
Methodologies to identify epitopes or ligands of the fungal cell wall polysaccharides influencing the immune response of human pathogens have to date been imperfect. Using the galactomannan (GM) of Aspergillus fumigatus as a model, we have shown that synthetic oligosaccharides of distinct structures representing key fragments of cell wall polysaccharides are the most precise tools to study the serological and immunomodulatory properties of a fungal polysaccharide.
Subject(s)
Antigens, Fungal/immunology , Aspergillus fumigatus/chemistry , Cell Wall/immunology , Mannans/immunology , Oligosaccharides/chemical synthesis , Oligosaccharides/immunology , Antigens, Fungal/chemistry , Aspergillosis/microbiology , Epitopes/chemistry , Epitopes/immunology , Galactose/analogs & derivatives , Humans , ImmunomodulationABSTRACT
During the course of fungal infection, pathogen recognition by the innate immune system is critical to initiate efficient protective immune responses. The primary event that triggers immune responses is the binding of Pattern Recognition Receptors (PRRs), which are expressed at the surface of host immune cells, to Pathogen-Associated Molecular Patterns (PAMPs) located predominantly in the fungal cell wall. Most fungi have mannosylated PAMPs in their cell walls and these are recognized by a range of C-type lectin receptors (CTLs). However, the precise spatial distribution of the ligands that induce immune responses within the cell walls of fungi are not well defined. We used recombinant IgG Fc-CTLs fusions of three murine mannan detecting CTLs, including dectin-2, the mannose receptor (MR) carbohydrate recognition domains (CRDs) 4-7 (CRD4-7), and human DC-SIGN (hDC-SIGN) and of the ß-1,3 glucan-binding lectin dectin-1 to map PRR ligands in the fungal cell wall of fungi grown in vitro in rich and minimal media. We show that epitopes of mannan-specific CTL receptors can be clustered or diffuse, superficial or buried in the inner cell wall. We demonstrate that PRR ligands do not correlate well with phylogenetic relationships between fungi, and that Fc-lectin binding discriminated between mannosides expressed on different cell morphologies of the same fungus. We also demonstrate CTL epitope differentiation during different phases of the growth cycle of Candida albicans and that MR and DC-SIGN labelled outer chain N-mannans whilst dectin-2 labelled core N-mannans displayed deeper in the cell wall. These immune receptor maps of fungal walls of in vitro grown cells therefore reveal remarkable spatial, temporal and chemical diversity, indicating that the triggering of immune recognition events originates from multiple physical origins at the fungal cell surface.
Subject(s)
Cell Wall/immunology , Fungi/immunology , Lectins, C-Type/immunology , Mannans/immunology , Mycoses/immunology , Phylogeny , Cell Adhesion Molecules/genetics , Cell Adhesion Molecules/immunology , Cell Wall/chemistry , Cell Wall/genetics , Fungi/chemistry , Fungi/classification , Fungi/genetics , Humans , Lectins, C-Type/genetics , Mannans/analysis , Mycoses/genetics , Mycoses/microbiology , Receptors, Cell Surface/genetics , Receptors, Cell Surface/immunologyABSTRACT
OBJECTIVE: To assess the diagnostic value of serum Candida mannan antigen (MN) and anti-mannan IgG and IgM antibodies for candidiasis. METHODS: This study was a prospective cohort study. Clinical data and venous blood samples from 23 medical centres in Beijing, China were collected between 1 January 2017 and 31 December 2018. All collected specimens were tested within one week for serum Candida MN and IgG and IgM antibodies using an ELISA kit. RESULTS: A total of 452 patients were enrolled, including 188 patients in the Candida exposure groups (56 patients with Candida bloodstream infection, 69 patients with Candida-positive tracheal aspirate cultures and 63 patients with Candida-positive urine cultures) and 264 patients in the control groups (212 healthy controls and 52 patients with bacteraemia). The receiver operating characteristic (ROC) curve of the 56 patients with Candida bloodstream infection and 212 healthy controls showed that serum MN and IgG had good diagnostic value. The area under the ROC curve (AUC) values were 0.812 (95% CI, 0.750-0.873) and 0.866 (95% CI, 0.808-0.924), respectively, wherein the MN specificity and sensitivity were 86.79% and 60.71%, and the IgG were 84.43% and 80.36%, respectively. The AUC of the combination of serum MN and IgG was 0.871(95% CI, 0.813-0.929), and the specificity and sensitivity were 93.87% and 57.14%. CONCLUSIONS: The serum levels of Candida MN and its IgG antibody have diagnostic value for Candida bloodstream infection, and combination of MN and IgG can improve diagnostic specificity and may provide a new approach for diagnosis of candidaemia.