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At least 19 recordsLinked to original sources
PubMed2006

Airborne exposure to wheat allergens: measurement by human immunoglobulin G4 and rabbit immunoglobulin G immunoassays.

BACKGROUND: Exposure to airborne wheat allergens in the bakery trade is associated with a high risk of occupational allergy and asthma. Control and reduction of allergen exposure require relatively simple but reliable monitoring techniques. We developed new rabbit IgG-based enzyme immunoassays (EIA) for wheat allergens, which might be a convenient alternative for the thus far used human IgG4 inhibition assay. METHODS: The reactivity and specificity of rabbit antibodies were assessed by EIA and immunoblotting, and compared with those of IgE from wheat-sensitized bakers, and with the antibodies used in the IgG4 inhibition EIA. An IgG inhibition and a sandwich EIA were developed for analysis of airborne dust samples. RESULTS: Human IgG4 and rabbit IgG inhibition EIAs had comparable sensitivities, with limits of detection (LOD) between 18 and 88 ng/mL, while the sandwich EIA was much more sensitive (LOD<0.2 ng/mL). Human IgG4 and rabbit IgG reacted in immunoblotting with most of the IgE-binding wheat proteins, although with quantitative differences. All three assays showed a strong reaction with wheat proteins, and some cross-reactivity with rye and barley, but were further highly specific for cereal flour proteins. Concentrations measured with the three EIAs in 432 airborne dust samples were highly correlated (r>0.95) and their absolute values showed less than 10-20% differences. CONCLUSION: The rabbit IgG EIAs are valid substitutes for the human IgG4 inhibition EIA, with important practical advantages. The inhibition EIA is recommended for routine wheat allergen measurements. The sandwich EIA may be used to measure low allergen levels, as in short task-related exposure measurements or in subfractions of airborne dust samples.

Air Pollutants, Occupational↗
PubMed2006

Close correlation between chronic sclerosing sialadenitis and immunoglobulin G4.

In four patients with chronic sclerosing sialadenitis, serum immunoglobulin G4 concentration was markedly increased and abundant infiltration of immunoglobulin G4-positive plasma cells was observed in the salivary glands. Autoimmune pancreatitis occurred in the two patients during follow up. Chronic sclerosing sialadenitis and autoimmune pancreatitis would appear to show essentially the same pathophysiological mechanism. Measurement of serum immunoglobulin G4 concentration is useful in differentiating chronic sclerosing sialadenitis from neoplasia.

Aged↗
PubMed2005

Mouse allergen-specific immunoglobulin G and immunoglobulin G4 and allergic symptoms in immunoglobulin E-sensitized laboratory animal workers.

BACKGROUND: High levels of allergen-specific IgG have been associated with clinical efficacy in immunotherapy studies, but whether this antibody isotype is associated with clinical tolerance in the setting of environmental exposure remains unclear. OBJECTIVE: To determine if mouse allergen-specific IgG (mIgG) and IgG4 (mIgG4) levels are associated with mouse-related symptoms among IgE-sensitized laboratory workers. METHODS: Fifty-eight workers with either skin test or serologic evidence of IgE-mediated mouse sensitization were studied. Symptom data were obtained by a questionnaire. Serum levels of mouse-specific IgG, IgG4, and IgE were quantified by a solid-phase antigen-binding assay (IgG) and RAST (IgG4 and IgE), and the relationships between mouse-specific serologic responses and mouse-related symptoms were analysed. RESULTS: Twenty-three (39.7%) participants reported mouse-related symptoms. Mouse-specific IgG and IgG4 levels were not associated with mouse-related symptoms among the study population as a whole. Among the 29 (50%) participants with detectable mouse-specific IgE (mIgE), higher mouse-specific IgG and IgG4 levels were associated with a decreased risk of symptoms, after adjusting for mIgE level (odds ratio (OR) 0.3, 95% confidence interval (CI): 0.1-1.4, and OR 0.3, 95% CI: 0.04-2.6, respectively). Higher levels of mIgG and mIgG4 remained associated with a decreased risk of symptoms after additional adjustment for sex and handling of mice (OR 0.1, 95% CI: 0.02-0.7, and OR 0.2, 95% CI: 0.02-2.1, respectively). Higher mIgG : IgE and mIgG4 : IgE ratios were also associated with a decreased risk of symptoms after adjusting for these confounders (OR 0.1, 95% CI: 0.02-0.7, and OR 0.2, 95% CI: 0.02-0.92, respectively). CONCLUSION: Among workers with detectable mIgE, higher mIgG and mIgG4 levels are associated with a decreased risk of mouse-related symptoms. High serum levels of mIgG or mIgG4 may be markers for clinical tolerance among laboratory mouse workers with detectable mIgE, but these findings need to be confirmed in larger, prospective studies.

Adult↗
PubMed1986

Immunoglobulin G4 in pigeon breeder's disease.

Immunoglobulin G4 has previously been implicated in the pathogenesis of pigeon breeder's disease (PBD), a form of hypersensitivity pneumonitis associated with inhalation of pigeon antigens. We investigated the presence of IgG4 antibody to antigens in pigeon dropping extracts (PDE) in the lungs of pigeon breeders. Seven of these subjects had symptoms of PBD and eight others had no symptoms. IgG4 antibody to PDE was compared with IgG3 levels because both were relatively minor subclasses, but IgG3 is not considered reaginic whereas IgG4 is. An increase in IgG4 antibody relative to IgG3 would therefore be considered a selective increase and suggest a role for this subclass in the development of PBD. Our results, however, indicated that pigeon breeders without symptoms had significantly higher levels of serum IgG4 and that there were no significant differences with regard to the lavage fluid levels of IgG4, IgG3, or total IgG antibody in the two groups of subjects. A tendency of higher IgG4 antibody levels was found in lavage fluid from subjects without symptoms. These results do not support the hypothesis that IgG4 may act as a reaginic trigger in the development of PBD symptoms.

Adult↗
PubMed1997

Interleukin-12 suppresses immunoglobulin E production but enhances immunoglobulin G4 production by human peripheral blood mononuclear cells.

The effect of interleukin-12 (IL-12) on human immunoglobulin G4 (IgG4) and IgE production was examined with cells derived from filarial patients and European controls. IL-12 inhibited IgE release but enhanced IgG4 production in cultures of peripheral blood mononuclear cells stimulated with anti-CD2 plus IL-2. When purified T- and B-cell cocultures were examined, IL-12 again markedly enhanced IgG4, whereas IgE production was no longer inhibited.

Animals↗
PubMed2004

Development of a chip-based capillary gel electrophoresis method for quantification of a half-antibody in immunoglobulin G4 samples.

A method based on microfluidic technology was developed to support quantitative analysis of recombinant monoclonal immunoglobulin G4 (IgG4) antibody samples. The assay was performed on an Agilent 2100 Bioanalyzer in combination with the Protein 200 Plus LabChip Kit and the Protein 200 Plus assay software. Capillary electrophoresis principles have been transferred to a chip format that integrates all separation, staining, virtual destaining, and detection steps. The method is referred to in this paper as chip-based capillary gel electrophoresis (GelChip-CE method). The GelChip-CE method under nonreducing conditions proved to be a quantitative test for half-antibody determination in IgG4 samples. Similar to the traditional nonreducing sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) method, the GelChip-CE method includes a denaturing step prior to separation. We showed that denaturing the sample by heating resulted in an artificial increase in the amount of half-antibody detected, which could be prevented by addition of N-ethylmaleimide to the sample buffer. The GelChip-CE method allowed for analysis of IgG4 samples with more accuracy, higher precision, and a faster turnaround time than SDS-PAGE and reversed-phase high-performance liquid chromatography (RP-HPLC).

Antibodies, Monoclonal↗
PubMed1988

A molecular-mechanics study of the conformation of the interchain disulfide of human immunoglobulin G4 (IgG4).

The conformation of the interchain disulfide bond between the light and the heavy chains of human immunoglobulin G4 (IgG4) was modeled based on the known structure of a human IgG1 Fab. Exploration of a large number of conformations followed by energy minimization using molecular mechanics methods rendered a plausible model for the disulfide. In this model the disulfide adopts the long, trans-gauche-trans configuration found in immunoglobulin intrachain bridges and not the conformations most commonly observed in other proteins (left-handed spiral or right-handed hook). Heavy chain residues H217 and H218 pack tightly against the disulfide and put restrictions on which sequences can exist in the proposed conformation. Sequence analysis at these positions shows that: (a) all human IgG4 and IgG3 are compatible with the model; (b) IgG2 and human immunoglobulins of other classes cannot adopt the conformation proposed for IgG4.

Disulfides↗
PubMedDate not supplied

Influence of infection with non-filarial helminths on the specificity of serological assays for antifilarial immunoglobulin G4.

Serological assays based on the detection of immunoglobulin (Ig) G4 antibodies to crude filarial extracts are widely used for epidemiological and diagnostic purposes. We tested 195 samples collected in 1998 from an area of Brazil where filariasis is not endemic and 13 (6.7%) had levels of antifilarial IgG4 antibodies that were defined as positive. Both Strongyloides infection and the presence of Strongyloides antibody responses were associated with higher antifilarial antibody responses. None of the specimens had a positive response to the Brugia malayi recombinant antigen (Bm14). These data suggest that serodiagnostic assays based on the use of crude filarial antigens should be interpreted with caution because of the potential for cross-reactivity with Strongyloides.

Adolescent↗
PubMed2002

Complete disulfide bond assignment of a recombinant immunoglobulin G4 monoclonal antibody.

Recombinant monoclonal antibodies (mAbs) are an emerging therapeutic area. However, there are few reports on disulfide bond assignment of recombinant mAbs. This work describes the complete disulfide bond assignment of a recombinant immunoglobulin G4 (IgG4) mAb. N-ethylmaleimide (NEM) was used to mask free sulfhydryl groups present in the mAb. Digestion of the mAb with endoproteinase Lys-C without disulfide scrambling was achieved by denaturing the mAb in the presence of NEM in guanidine hydrochloride (GuHCl). The Lys-C digest was subsequently reduced with dithiothreitol (DTT). Native and reduced Lys-C digests were mass analyzed by on-line reversed-phase-high-performance liquid chromatography mass spectrometry (RP-HPLC/MS). Disulfide-containing peptides were sequenced by off-line nanoelectrospray quadrupole time-of-flight mass spectrometry (nanoESI-QTOF MS) and N-terminal Edman sequencing for verifying connectivities. The recombinant IgG4 mAb was found to contain the expected disulfide linkages with the proposed method. The NEM alkylating reagent was critical in minimizing disulfide scrambling during the denaturation and digestion of the mAb. This integrated approach, combining MS and N-terminal Edman sequencing, was capable of assigning the disulfide pattern of the IgG4 mAb rapidly and completely, and should be applicable for disulfide bond assignment and structural analysis of other mAbs and large proteins with multiple disulfide bonds.

Amino Acid Sequence↗
PubMed2006

Role of CYP2E1 immunoglobulin G4 subclass antibodies and complement in pathogenesis of idiosyncratic drug-induced hepatitis.

Idiosyncratic drug-induced hepatitis (IDDIH) is the third most common cause for acute liver failure in the United States. Previous studies have attempted to identify susceptible patients or early stages of disease with various degrees of success. To determine if total serum immunoglobulin subclasses, CYP2E1-specific subclass autoantibodies, complement components, or immune complexes could distinguish persons with IDDIH from others exposed to drugs, we studied persons exposed to halogenated volatile anesthetics, which have been associated with IDDIH and CYP2E1 autoantibodies. We found that patients with anesthetic-induced IDDIH had significantly elevated levels of CYP2E1-specific immunoglobulin G4 (IgG4) autoantibodies, while anesthetic-exposed healthy persons had significantly elevated levels of CYP2E1-specific IgG1 autoantibodies. Anesthetic IDDIH patients had significantly lower levels of C4a, C3a, and C5a compared to anesthetic-exposed healthy persons. C1q- and C3d-containing immune complexes were significantly elevated in anesthetic-exposed persons. In conclusion, our data suggest that anesthetic-exposed persons develop CYP2E1-specific IgG1 autoantibodies which may form detectable circulating immune complexes subsequently cleared by classical pathway activation of the complement system. Persons susceptible to anesthetic-induced IDDIH develop CYP2E1-specific IgG4 autoantibodies which form small, nonprecipitating immune complexes that escape clearance because of their size or by direct inhibition of complement activation.

Adult↗
PubMed1997

Association of Leishmania heat shock protein 83 antigen and immunoglobulin G4 antibody titers in Brazilian patients with diffuse cutaneous leishmaniasis.

Diffuse cutaneous leishmaniasis (DCL) is characterized by the presence of numerous nonulcerated nodules and plaques containing large numbers of Leishmania amazonensis parasites and few lymphoid elements. The immune responses of DCL patients reflect severe antigen-specific T-cell deficiencies, while the antibody response to Leishmania antigens is often accentuated. We report herein on the Leishmania antigen-specific antibody subclass distribution in DCL patients and demonstrate that a dominant antigen contributing to the biased immunoglobulin G4 antibody subclass in sera of DCL patients is Leishmania heat shock protein 83.

Animals↗
PubMed2005

Ancylostoma duodenale infection: a study of serum immunoglobulin G4 response to the excretory secretory antigen of adult worm.

The serum anti-Ancylostoma duodenale immunoglobulin (Ig) G4 antibody response to fraction III of the partially purified excretory secretory antigen of adult worm (Ad III ESA) was studied. The work included 60 patients with A. duodenale infection (GI), 40 patients with other parasitic infections (GII) and 30 apparently healthy parasite-free controls (GIII). Level of serum specific IgG4 was measured by indirect enzyme linked immunosorbent assay and compared with serum specific IgG, IgG 1, 2 & 3 subclass antibodies. Patients of GI had gastro-intestinal manifestations and symptoms suggestive of anaemia, and by investigations they had anaemia in 31.7% & eosinophilia in 100%. Measuring the intensity of A. duodenale infection, quantified as fecal egg counts, in patients of GI revealed that 60%, 30% & 10% had light, moderate, and heavy infections, respectively. The serum anti-Ad III ESA IgG & IgG 1-4 subclass antibodies were significantly elevated (P < 0.001) in patients of GI compared with GIII. Serum specific IgG4 was expressed in 100% of patients of GI at a significantly highly elevated level than IgGI (P < 0.01), IgG2 & IgG3 (P < 0.001). Specific IgG1 was expressed in 88.3% of patients of GI at a significantly elevated level (P < 0.001) than IgG2 & IgG3 which were expressed in 31.7% & 38.3%, respectively and elevated to a moderate extent. Serum specific IgG4 showed a 1.0, 1.1, 3.1 & 2.6-fold increase in detection rate of positive cases than IgG, IgG1, IgG2 & IgG3, respectively. The highest ability to differentiate between infected and healthy subjects was by serum specific IgG4 recording a discrimination coefficient of 9.4, while IgG, IgG1, IgG2 & IgG3 recorded 5.2, 6.3, 3.2 & 3.4, respectively. Serum specific IgG4 showed a significant positive correlation (r = 0.41, P < 0.001) with the intensity of A. duodenale infection, as was demonstrated by IgG & IgG3 (P < 0.01 & P < 0.05, respectively). Detection of serum anti-Ad III ESA IgG4 antibody recorded a 100% sensitivity that was significantly higher (P < 0.001) than IgG1, IgG2 & IgG3, but insignificantly different (P > 0.05) from IgG. Finally, serum specific IgG4 recorded a 100% specificity that was significantly higher than IgG, IgG2, IgG3 (P < 0.01) & IgG1 (P < 0.05). They showed cross-reactions with ascariasis, lymphatic filariasis and strongyloidiasis. The results are discussed.

Adolescent↗
PubMed1998

Molecular characterization of immunoglobulin G4 gene isoallotypes.

The molecular bases of classical serological immunoglobulin allotypes are progressively uncovered through detailed characterization of the relevant genes. Here we describe two isoallotypic determinants of the G4 gene. In the first, Leu 309, as in G1 and G3, is changed to Val, as in G2; studies on myeloma proteins have long assigned the immunologically defined nG4 m(a)/(b) to the same position. The two molecular variants, here called IGHG4*L309 and IGHG4*V309, are allelic in IGHC haplotypes with a single G4 gene, but can be found together in cis in G4-duplicated haplotypes. A second isoallotypic variant was found at codon 409, where either Arg, as in G1 and G3, or Lys, as in G2, can be found. Both isoallotypes are associated with several 'silent isoallotypic' substitutions dispersed through the hinge, CH2 and CH3 domains. This suggests segmental gene conversion as the common mechanism of origin.

Base Sequence↗
PubMed1983

Immunoglobulin E and immunoglobulin G4 antibodies to cow's milk in children with cow's milk allergy.

The presence of cow's milk specific antibodies of immunoglobulin E and G4 classes were studied in 47 children with a positive clinical history of cow's milk allergy. The children were challenged with cow's milk orally. The clinical diagnosis was verified by immediate reactions in 25 patients while 22 had late reactions or were provocation test negative in spite of the clinical history. There was no relation between levels of cow's milk specific IgG4 antibodies and provocation test results, i.e. neither with immediate or late reactions. Total IgE was elevated above +1 SD for age in 31 of 41 tested patients. Of these, 29 had immediate type reactions to cow's milk, wheat flour and/or egg white, while only two of 10 children with IgE of less than +1 SD had a demonstrable allergy to any of these foods. The sensitivity of the total IgE determinations for the diagnosis of food allergy was 94% and the specificity was 80%. Specific IgE antibodies to cow's milk were demonstrated in 11 of 14 children with immediate reactions and in three of 15 who were provocation test negative or had only late reactions. This means a sensitivity of 79% and a specificity of 80%. At least one of the four patients with specific IgE but negative provocation test results had earlier shown an immediate reaction when challenged with cow's milk, indicating that the specific IgE antibodies were not truly "false" positive reactions but a consequence of previous allergy. Our results confirm an association between elevated total serum IgE and food allergy and an association between positive RAST to cow's milk and positive provocations in young children. We did not find any evidence for specific IgG4 antibodies playing a role in these patients.

Animals↗
PubMed1999

Normal human immunoglobulin G4 is bispecific: it has two different antigen-combining sites.

Unlike other immunoglobulin G (IgG) subclasses, IgG4 antibodies in plasma have been reported to be functionally monovalent. In this paper we show that the apparent monovalency of circulating IgG4 is caused by asymmetry of plasma IgG4. A large fraction of plasma IgG4 molecules have two different antigen-binding sites, resulting in bispecificity. Sera from patients with IgG4 antibodies to both house dust mite and grass pollen induced cross-linking of Sepharose-bound grass pollen antigen to radiolabelled house dust mite allergen Der p I. This bispecific binding activity was not observed in sera with IgG4 antibodies to either grass pollen or house dust mite exclusively. Depletion of IgG4 antibodies resulted in disappearance of the bispecific activity. By size exclusion chromatography we excluded the possibility that bispecific activity was caused by aggregation of IgG4 antibodies. These results indicate that circulating (polyclonal) IgG4 antibodies have two different antigen-binding sites and therefore are functionally monovalent antibodies.

Allergens↗
PubMed1981

Selective immunoglobulin G4 deficiency and recurrent infections of the respiratory tract.

Using a newly developed radioimmunoassay, 4 of 422 subjects tested were found to have an isolated absence of the immunoglobulin subclass IgG4. All had severe recurrent sinopulmonary infection. The association of these disorders with an isolated absence of IgG4 suggested that this immunoglobulin subclass may have a unique role in host respiratory tract defense mechanisms.

Adolescent↗
PubMed1993

An interleukin 4 (IL-4) mutant protein inhibits both IL-4 or IL-13-induced human immunoglobulin G4 (IgG4) and IgE synthesis and B cell proliferation: support for a common component shared by IL-4 and IL-13 receptors.

Interleukin 4 (IL-4) and IL-13 share many biological functions. Both cytokines promote growth of activated human B cells and induce naive human surface immunoglobulin D+ (sIgD+) B cells to produce IgG4 and IgE. Here we show that a mutant form of human IL-4, in which the tyrosine residue at position 124 is replaced by aspartic acid (hIL-4.Y124D), specifically blocks IL-4 and IL-13-induced proliferation of B cells costimulated by anti-CD40 mAbs in a dose-dependent fashion. A mouse mutant IL-4 protein (mIL-4.Y119D), which antagonizes the biological activity of mouse IL-4, was ineffective. In addition, hIL-4.Y124D, at concentrations of up to 40 nM, did not affect IL-2-induced B cell proliferation. hIL-4.Y124D did not have detectable agonistic activity in these B cell proliferation assays. Interestingly, hIL-4.Y124D also strongly inhibited both IL-4 or IL-13-induced IgG4 and IgE synthesis in cultures of peripheral blood mononuclear cells, or highly purified sIgD+ B cells cultured in the presence of anti-CD40 mAbs. IL-4 and IL-13-induced IgE responses were inhibited > 95% at a approximately 50- or approximately 20-fold excess of hIL-4.Y124D, respectively, despite the fact that the IL-4 mutant protein had a weak agonistic activity. This agonistic activity was 1.6 +/- 1.9% (n = 4) of the maximal IgE responses induced by saturating concentrations of IL-4. Taken together, these data indicate that there are commonalities between the IL-4 and IL-13 receptor. In addition, since hIL-4.Y124D inhibited both IL-4 and IL-13-induced IgE synthesis, it is likely that antagonistic mutant IL-4 proteins may have potential clinical use in the treatment of IgE-mediated allergic diseases.

Antigens, CD↗