Relation of antigenic structure of cereal proteins to their toxicity in coeliac patients

1985 ◽  
Vol 53 (1) ◽  
pp. 39-45 ◽  
Author(s):  
P. J. Ciclitira ◽  
H. J. Ellis ◽  
D. J. Evans ◽  
E. S. Lennox
Keyword(s):  
Coeliac Disease ◽  
Competitive Inhibition ◽  
Double Diffusion ◽  
Cross Reactivity ◽  
Antigenic Structure ◽  
Partial Identity ◽  
Cereal Proteins

1. Unfractionated gliadin and its α-, β-, γ- and ω-gliadin subfractions were used as rabbit immunogens. The antisera were characterized by (1) Ouchterlony double diffusion, (2) binding of 125I-labelled gliadin subfractions, (3) inhibition by several gliadin subfractions of binding between γgliadin antiserum and 125I-labeIled γgliadin.2. Double diffusion showed identical cross-reactivity between the antisera and the gliadin subfractions with the exception of ω-gliadin. Precipitin lines of partial identity with gliadin were observed against rye secalins and barley hordeins but not oat avenins or maize zeins.3. Binding was observed between unfractionated 125I-labelledα-, β-, γ- and ω-gliadins and all the antisera. There was binding of 125I-labelled ω-gliadin to the ω-gliadin antiserum but poor binding of 125I-labelled ω-gliadin to unfractionated α-, β- and γ-gliadin antisera. Competitive inhibition of binding between 125I-labelled γ-gliadin and γ-gliadin antiserum diluted 1:250 (v/v) demonstrated similar competition between α-, β- and γ-gliadins and this antiserum but poor competition between ω-gliadin, wheat glutenins, albumins and globulins, rye secalins, barley hordeins and oat avenins.4. These findings suggest that there is a good correlation between the antigenic structure of gliadin proteins and their toxicity to patients with coeliac disease.

scholarly journals Antibodies in human sera to oncorna virus-like proteins from normal or leukemia marrow cell cultures.

1976 ◽  
Vol 144 (5) ◽  
pp. 1243-1253 ◽  
Author(s):  
S Louie ◽  
J E Curtis ◽  
J E Till ◽  
E A McCulloch
Keyword(s):  
Lupus Erythematosus ◽  
Competitive Inhibition ◽  
Marrow Cell ◽  
Leukemia Virus ◽  
Polyacrylamide Gel Electrophoresis ◽  
Cross Reactivity ◽  
Antibody Activity ◽  
Human Sera ◽  
Blood Specimens ◽  
Radioimmunoprecipitation Assay

Some human marrows in culture release particles with oncornavirus-like properties. This study was designed to examine the immunological properties of similar particles in human marrow culture supernates. Leukemic and nonleukemic marrows were cultured for 5-7 days in the presence of [14C]uridine and [3H]leucine or [3H]glucosamine. Labeled supernatant components banding in sucrose gradient densities of 1.20-1.24 g/ml were used as antigen in a double antibody immunoprecipitation assay. The assay was validated by end point titrations and competition with unlabeled antigen; purified myeloma proteins were used as negative controls. Cross-reactivity with mammalian oncornaviruses, as judged by competitive inhibition of precipitation by these viruses, was slight and at the border of the sensitivity of the method. Precipitated antigens analyzed by SDS polyacrylamide gel electrophoresis contained three distinct polypeptides of about 70,000, 45,000 and 30,000 mol wt; these comigrated with the gp 70, pg 45, and p 30 of a murine leukemia virus. Similar polypeptides were obtained from both leukemic and nonleukemic marrow culture supernates. As determined by the radioimmunoprecipitation assay, 32 of 45 leukemic sera (71%), 36 of 45 normal sera (80%), 15 of 19 sera from family contacts of leukemic patients (79%), 14 of 21 cord blood specimens (67%), and 21 of 23 sera (91%) from patients with systemic lupus erythematosus had detectable antibody activity.

scholarly journals Cross-Reactivity between Chemical Antibodies Formed to Serum Proteins and Thyroid Axis Target Sites

2020 ◽  
Vol 21 (19) ◽  
pp. 7324
Author(s):  
Datis Kharrazian ◽  
Martha Herbert ◽  
Aristo Vojdani
Keyword(s):  
Conformational Change ◽  
Protein Misfolding ◽  
Serum Proteins ◽  
Cross Reactivity ◽  
Surface Topology ◽  
Antigenic Structure ◽  
Thyroid Peroxidase ◽  
Immune Reactivity ◽  
Target Sites ◽  
Thyroid Axis

In some instances, when chemicals bind to proteins, they have the potential to induce a conformational change in the macromolecule that may misfold in such a way that makes it similar to the various target sites or act as a neoantigen without conformational change. Cross-reactivity then can occur if epitopes of the protein share surface topology to similar binding sites. Alteration of peptides that share topological equivalence with alternating side chains can lead to the formation of binding surfaces that may mimic the antigenic structure of a variant peptide or protein. We investigated how antibodies made against thyroid target sites may bind to various chemical–albumin compounds where binding of the chemical has induced human serum albumin (HSA) misfolding. We found that specific monoclonal or polyclonal antibodies developed against thyroid-stimulating hormone (TSH) receptor, 5′-deiodinase, thyroid peroxidase, thyroglobulin, thyroxine-binding globulin (TBG), thyroxine (T4), and triiodothyronine (T3) bound to various chemical HSA compounds. Our study identified a new mechanism through which chemicals bound to circulating serum proteins lead to structural protein misfolding that creates neoantigens, resulting in the development of antibodies that bind to key target proteins of the thyroid axis through protein misfolding. For demonstration of specificity of thyroid antibody binding to various haptenic chemicals bound to HSA, both serial dilution and inhibition studies were performed and proportioned to the dilution. A significant decline in these reactions was observed. This laboratory analysis of immune reactivity between thyroid target sites and chemicals bound to HSA antibodies identifies a new mechanism by which chemicals can disrupt thyroid function.

Immunological Studies of Catechol Methyltransferase from the Yeast Candida tropicalis

1980 ◽  
Vol 35 (9-10) ◽  
pp. 712-716 ◽  
Author(s):  
Joseph Veser ◽  
Helmut Thomas
Keyword(s):  
Candida Tropicalis ◽  
Specific Antigen ◽  
Double Diffusion ◽  
Bovine Liver ◽  
Inhibitory Effect ◽  
Cross Reactivity ◽  
Diffusion Analysis ◽  
Potent Inhibitory Effect ◽  
Catechol Methyltransferase ◽  
Antigen Antibody

Abstract Immunization of rabbits with purified catechol methyltransferase from Candida tropicalis yielded a potent antiserum. Ouchterlony double diffusion analysis showed a single precipitin line. There was no cross reactivity with the catechol methyltransferase from rat and bovine liver. Specific antigen-antibody interaction was demonstrated by a potent inhibitory effect of the antibody on the yeast enzyme. Immunological titration and quantitative precipitin reaction of the enzyme showed that the maximum amount of precipitable complex occurred at the equivalence point where enzyme activity was completely inhibited.

scholarly journals IMMUNOLOGIC CROSS-REACTIONS AMONG MAMMALIAN ACUTE PHASE PROTEINS

1960 ◽  
Vol 111 (4) ◽  
pp. 441-451 ◽  
Author(s):  
Emil Gotschlich ◽  
Chandler A. Stetson
Keyword(s):  
Acute Phase ◽  
Guinea Pigs ◽  
Acute Phase Proteins ◽  
Double Diffusion ◽  
Cross Reactivity ◽  
C Reactive Protein ◽  
Skin Reactions ◽  
Cross Reactions ◽  
Reactive Protein

Crystalline rabbit Cx-reactive protein has been compared immunologically with the analogous crystalline C-reactive protein of man. Immunologic cross-reactivity has been demonstrated between the acute phase proteins of man, rabbit, and monkey. Double-diffusion reactions in agar and passive cutaneous anaphylaxis reactions in vivo both indicate that these acute phase proteins are antigenically closely similar but not identical. Guinea pigs with delayed hypersensitivity to C-reactive protein exhibit delayed skin reactions when tested with Cx-reactive protein and vice versa.

scholarly journals Immunological discrimination of diverse forms of human alpha 1-proteinase inhibitor.

1996 ◽  
Vol 43 (3) ◽  
pp. 481-487 ◽  
Author(s):  
I Wawrzos ◽  
Y Kitagawa ◽  
H Kołoczek
Keyword(s):  
Proteinase Inhibitor ◽  
Competitive Inhibition ◽  
Immunological Response ◽  
Cross Reactivity ◽  
Reactive Site ◽  
Latent Form ◽  
Mild Conditions ◽  
Inhibition Elisa ◽  
Inhibition Data ◽  
Elisa Data

The immunodiffusion cross-reactivity and competitive inhibition ELISA assays were used for immunological differentiation of latent form, cleaved form and guanidinium hydrochloride (GuHCl) induced polymer of human alpha 1-proteinase inhibitor (alpha 1-PI). Under the conditions studied, the differences between latent form and GuHCl-induced polymers of the inhibitor in terms of immunological response were estimated to amount to about 30% and differences between latent and cleaved alpha 1-PI to about 50%. The immunodiffusion and ELISA data for citrate-induced polymers suggest that in their structure the latent molecule is involved. On the basis of competitive inhibition data, we suggest that the alpha 1-PI protein polymerisation involves insertion of the reactive-site loop (RSL) into the A-sheet under mild conditions and that in the latent form of the inhibitor RSL is incompletely inserted into the A-sheet.

Determination of Methyl 2-Benzimidazolecarbamate in Blueberries by Competitive Inhibition Enzyme Immunoassay

1992 ◽  
Vol 75 (2) ◽  
pp. 323-327 ◽  
Author(s):  
Rodney J Bushway ◽  
Jasotha Ugabalasooriar ◽  
Lewis B Perkins ◽  
Robert O Harrison ◽  
Barbara E S Young ◽  
...  
Keyword(s):  
Enzyme Immunoassay ◽  
Methylene Chloride ◽  
Methanol Extract ◽  
Competitive Inhibition ◽  
Cross Reactivity ◽  
Dietary Risk ◽  
Coefficients Of Variation ◽  
Field Samples ◽  
Dietary Risk Assessment

Abstract A polyclonal enzyme Immunoassay (EIA) method was developed that will quantitate methyl 2- benzlmidazolecarbamate (MBC), the degradation product of benomyl, In blueberries. The entire analysis Is completed within 25 min, and up to 8 samples can be analyzed simultaneously with a detection limit of 18 ppb. The assay response was linear from 0.69 to 22 ppb MBC. Cross-reactivity was confined to the benzimidazole and dicarboxlm- Ide type pesticides. Intra-assay percent coefficients of variation (% CVs) ranged from 3.4 to 18.4 for the standards, and from 3.2 to 20.6 for the samples. Interassay % CVs varied from 7.5 to 22.3 for the standards, and from 7.5 to 22.0 for the samples. Correlation coefficient between immunoassay and liquid chromatography was 0.87 for the methanol extract and 0.98 for the methylene chloride partition of the methanol extract containing 100 mL 1% sodium chloride. None of the 40 field samples analyzed approached the tolerance of 15 ppm (mean of 20 positive samples was 55 ppb). The ability of the EIA to monitor MBC easily and Inexpensively at concentrations far below the tolerance has major implications for current dietary risk assessment methods.

scholarly journals Development of a Cartilage Oligomeric Matrix Protein Neo-Epitope Assay for the Detection of Intra-Thecal Tendon Disease

2020 ◽  
Vol 21 (6) ◽  
pp. 2155
Author(s):  
Roger Smith ◽  
Patrik Önnerfjord ◽  
Kristin Holmgren ◽  
Shacko di Grado ◽  
Jayesh Dudhia
Keyword(s):  
Molecular Marker ◽  
Cartilage Oligomeric Matrix Protein ◽  
Matrix Protein ◽  
Competitive Inhibition ◽  
Objective Assessment ◽  
Clinical Signs ◽  
Tendon Injury ◽  
Cross Reactivity ◽  
Polyclonal Antiserum ◽  
Synovial Fluids

The diagnosis of tendon injury relies on clinical signs and diagnostic imaging but imaging is subjective and does not always correlate with clinical signs. A molecular marker would potentially offer a sensitive and specific diagnostic tool that could also provide objective assessment of healing for the comparison of different treatments. Cartilage Oligomeric Matrix Protein (COMP) has been used as a molecular marker for osteoarthritis in humans and horses but assays for the protein in tendon sheath synovial fluids have shown overlap between horses affected by tendinopathy and controls. We hypothesized that quantifying a COMP neoepitope would be more discriminatory of injury. COMP fragments were purified from synovial fluids of horses with intra-thecal tendon injuries and media from equine tendon explants, and mass spectrometry of a consistent and abundant fragment revealed a ~100 kDa COMP fragment with a new N-terminus at the 78th amino-acid (NH2-TPRVSVRP) located just outside the junctional region of the protein. A competitive inhibition ELISA based on a polyclonal antibody raised to this sequence yielded more than a 10-fold rise in the mean neoepitope levels for tendinopathy cases compared to controls (5.3 ± 1.3 µg/mL (n = 7) versus 58.8 ± 64.3 µg/mL (n = 13); p = 0.002). However, there was some cross-reactivity of the neoepitope polyclonal antiserum with intact COMP, which could be blocked by a peptide spanning the neoepitope. The modified assay demonstrated a lower concentration but a significant > 500-fold average rise with tendon injury (2.5 ± 2.2 ng/mL (n = 6) versus 1029.8 ± 2188.8 ng/ml (n = 14); p = 0.013). This neo-epitope assay therefore offers a potentially useful marker for clinical use.

scholarly journals Identification of common epitopes on gliadin, enterocytes, and calreticulin recognised by antigliadin antibodies of patients with coeliac disease

Gut ◽  
1999 ◽  
Vol 44 (2) ◽  
pp. 168-173 ◽  
Author(s):  
S Krupičková ◽  
L Tučková ◽  
Z Flegelová ◽  
M Michalak ◽  
J R F Walters ◽  
...  
Keyword(s):  
Amino Acids ◽  
Glutamic Acid ◽  
Affinity Chromatography ◽  
Coeliac Disease ◽  
Central Region ◽  
Inhibitory Effect ◽  
Cross Reactivity ◽  
Competitive Elisa ◽  
Terminal Region ◽  
Antigliadin Antibodies

BackgroundSera of patients with coeliac disease, containing IgA and IgG antigliadin antibodies (AGA) and various IgA autoantibodies, react with isolated enterocytes. AGA cross react with enterocyte antigens, one of which has been identified as calreticulin.AimsTo characterise the antigenic structures of gliadin, enterocytes, and calreticulin recognised by AGA from patients with active coeliac disease.MethodsAGA were isolated from sera of nine patients by affinity chromatography and tested by competitive ELISA using 40 α-gliadin synthetic dodecapeptides (A1–F6).ResultsReactivity of gliadin with all purified AGA tested was inhibited by peptide A4 at the N-terminal region; by C2, C3, and D4 at the central region; and by F3 and F4 at the C-terminal region of the gliadin molecule. AGA cross reactivity with enterocytes was inhibited by peptides A4, D1–D4, and F6 and with calreticulin by peptides A4, D3, and D4. As dominant epitopes AGA of coeliac patients recognise similar structures corresponding to peptides A4, D3, D4, and F6 present on gliadin, enterocytes, and calreticulin. Substitution of glutamine in the A4 peptide by glutamic acid caused loss of inhibitory capacity. Shortening of peptide A4 on the N-terminal by three amino acids increased its inhibitory effect.ConclusionsAGA of patients with coeliac disease react with similar structures on gliadin and potential autoantigens on enterocytes.

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