Monoclonal hybridoma antibodies against human IgE and their use in a rapid and sensitive enzyme immunoassay for the semiquantitative assessment of total IgE levels in human blood

Analysis of total immunoglobulin E and specific immunoglobulin E of 3,721 patients with allergic disease

Due to the increase in the prevalence and incidence of allergic diseases, improving the sensitivity and specificity of screening indexes is critical. Total immunoglobulin E (IgE) is a traditional index for judging allergic diseases, while its specificity is relatively poor. Serum-specific IgE (sIgE) is an objective index with high specificity in the diagnosis of allergic diseases. In the present research, the total IgE and sIgE of 3,721 patients with allergic diseases were analyzed to further illuminate the association between them. The data were derived from 3,721 patients. The serum-sIgE to 14 types of common allergens and total IgE were detected. A total of 2,419 cases (65.0%) of 3,721 patients exhibited increasing total IgE and 1,215 patients (32.7%) exhibited positive sIgE. The consistency rate of the two indexes was 60.4%, and the κ-value was 0.28. In 135 patients with normal total IgE, 82.2% exhibited one sIgE positive and 17.8% exhibited two or more sIgE positive. While the number of positive sIgE increased and the detecting level enhanced, the number of positive total IgE markedly increased. Patients (84.1%) with increasing total IgE were associated with positive sIgE, but the increase of total IgE could not be completely explained by the total accumulation of sIgE. Total IgE may play an important role on screening allergic disease while sIgE could be used as crucial evidence for allergy diagnosis. Although the consistency of the two methods was poor, neither total IgE nor sIgE could replace each other. Combining the two indexes with clinical manifestations together will improve the method.

Production and characterisation of monoclonal antibodies recognising ovine IgE

Two monoclonal antibodies (mAbs), XB6 and YD3, which recognise ovine immunoglobulin E (IgE) were produced. Mast cells isolated from ovine intestinal mucosa were used as a source of IgE to immunize mice. Culture supernatants of hybridomas were screened by immunoassays on small-intestine tissue sections, isolated mucosal cells, and dot blots of lysed mast cell homogenate. Two mAbs were chosen for their specific binding to mast cells. Antigen bound by these mAbs was purified by immunoaffinity chromatography using XB6 mAb, and this produced two bands consistent with IgE heavy chain (86,000 Daltons) and immunoglobulin light chain (28,000 Daltons) when run under reducing conditions on SDS-PAGE gels. Purified IgE was shown on dot blots to react weakly with mAb to chimeric ovine IgE and strongly to polyclonal anti-sheep antibodies. The two mAbs induced an immediate hypersensitivity-like reaction when injected into the skin of sheep. The mAbs bound to mast cells and other mononuclear cells, presumably IgE-secreting B-cells in mesenteric lymph node sections. These mAbs proved useful for detecting IgE-bearing cells in various ovine tissues, for purifying mast cells from cell isolates by panning and immunomagnetic bead separation, for purifying serum IgE using immunoaffinity chromatography and for detecting IgE in an ELISA. Competitive binding assays showed that the two mAbs bind to different epitopes on IgE. These mAbs will be useful in research applications and in diagnostic assays.

An automated ELISA system using a pipette tip as a solid phase and a pH-sensitive field effect transistor as a detector

A fully automated ELISA system was constructed using a pipette tip as a solid phase, urease as a detecting enzyme, and a pH-FET as a detector of urease activity. The inner wall of the end part of a pipette tip was used as a solid phase, and the urease activity of the conjugate, captured after a two-step immunoreaction, was measured by coupling the pipette tip with the pH-FET in a pH-measuring cell. Full automation of the ELISA system was achieved by using a disposable reagent cartridge and three pipetters for all mechanical operations, including sample dilution and B/F separation. This system can treat 60 samples per hour with an assay time of 21 min for all assay configurations. The system was applied to two-step sandwich assays for AFP, CEA, HBsAg, and HBsAb, a two-step competition assay for HBcAb, and a second antibody assay for HTLV-I Ab.

Detection of the products of polymerase chain reaction by an ELISA system based on an ion sensitive field effect transistor

An ELISA system was developed using a pH sensitive ISFET (pH-FET) as a detector, a pipette tip as a solid phase, and urease as a detecting enzyme. Double stranded PCR products with digoxigenin and biotin at both terminals were obtained by using digoxigenin- and biotin-labeled primers. 1 microliters of the PCR solution was directly introduced into the end part of a pipette tip coated with anti-digoxigenin antibody. Biotin-labeled PCR products captured at the solid phase were detected with avidin-urease, of which the activity was measured by a pH-FET in a pH-measuring cell containing urea solution. The assay was used to detect HTLV-I provirus gene integrated in the genome of a human MT-1 cell, and it was found that 100 pg of the genomic DNA of MT-1 cell was specifically detectable after 35 cycles of PCR. Also the detection limit of the present ELISA system itself was determined by using known amounts of purified PCR product labeled with digoxigenin and biotin, and it was found that 10 amol of the labeled DNA in 1 microliter of sample was detectable.

Production and characterization of mouse monoclonal antibodies directed against canine IgE and IgG

Immediate-type hypersensitivity reactions have been studied infrequently in dogs, in part because of limited availability of antisera specific for canine IgE. A series of murine hybridoma cell lines were prepared, that produced monoclonal antibodies (MAb) with specificity for canine immunoglobulin E (IgE) and IgG. The MAb were tested for their ability to induce a reverse cutaneous anaphylaxis reaction in dog skin, to neutralize the Prausnitz-Küstner reactivity of atopic dog serum, to serve as a ligand in immunoaffinity chromatography, and to bind to IgE and other Ig subclasses in several ELISA systems. Some of the MAb produced were found to be specific for canine IgE. Other MAb recognized common or similar determinants on IgE and IgG, or on IgG and IgM, though with apparently differing affinities. Heat or acid treatment of canine IgE abolished most, but not all, of the reactivity with the anti-IgE MAb. These MAb will be useful for further study of IgE-mediated phenomena in the dog.

Evaluation of a urease-based confirmatory enzyme-linked immunosorbent assay for diagnosis of Neisseria gonorrhoeae

A new urease-based enzyme-linked immunosorbent assay utilizing novel monoclonal antibodies was evaluated for the culture confirmation of Neisseria gonorrhoeae, with 270 isolates of N. gonorrhoeae, 56 isolates of diverse Neisseria spp., and 29 Moraxella isolates. The test was highly specific (100.00%) and sensitive (97.83%). No cross-reactions were observed with any of the Neisseria or Moraxella isolates tested. Fifty percent (3 of 6) of the false-negative results were obtained with isolates of serovar IA-4, a serovar rarely encountered in North America.

An assessment of urease-based enzyme-linked immunosorbent assay

The use of urease in enzyme-linked immunosorbent assays (ELISAs) offers the advantages of convenience and safety. However, urease-based ELISA, performed in standard microtitre format, could result in false positive reactions upon prolonged incubation. False positive reactions appeared when wells containing substrate solution absorbed ammonia liberated from a reactive well nearby. Thus, the intensity of the false reaction was proportional to that of the urease reaction. The transfer of ammonia was demonstrated by pyrolysis-mass spectrometry. When urease conjugates were compared with peroxidase conjugates in the detection of IgG and IgM, there was no evidence that one enzyme was superior to the other in terms of increasing the sensitivity or the speed of ELISA.

Generation and characterization of murine monoclonal antibodies specific for bovine immunoglobulin E

Monoclonal antibodies were produced against serum-derived bovine immunoglobulin E (IgE). Culture supernatants of hybridomas were initially screened by enzyme-linked immunosorbent assay (ELISA). Supernatant-derived antibodies were concentrated and further characterized using ELISA, reverse cutaneous anaphylaxis, immunohistochemical staining, and immunoblotting of IgE-containing samples separated by SDS-polyacrylamide gel electrophoresis (PAGE). Eight monoclonal antibodies showed specificity for bovine epsilon immunoglobulin heavy chain. Two antibodies (E2 and E32) reacted in immunoblots of SDS-PAGE of serum IgE under reducing conditions. Additionally, E2, E5, and E32 detected epsilon chain in serum separated by SDS-PAGE and then renatured. Antigen-specific IgE was detected in Western blots by E5 and E32. Immunoperoxidase staining of IgE-containing cells in mesenteric lymph node sections was detected with E5, E21 and E32. All eight antibodies produced positive reverse cutaneous anaphylaxis reactions in calf skin. All functioned well in ELISA as a plate-sensitizing reagent for quantitation of total IgE; E5 and E32 worked well as a primary antibody in antigen-specific IgE assays. These antibodies will be useful in research applications and in diagnostic assays.

Conformational differences of human IgE on hydrophobic and hydrophilic solid phases detected by monoclonal antibodies

Very sensitive assays of IgE are required for determining prevalence of allergic reactions in children. In order to develop a sensitive two-site IRMA two kinds of mAb were produced. Antibodies specific for D epsilon 1 determinants were derived from immunization with a 40 kDa papain Fc fragment. They bound equally native and 56 degrees C heated IgE. D epsilon 2 specific mAb were obtained after immunization with IgE anti-D epsilon 1 complex and were selected on the basis of their inability to bind heated IgE. In a two-site assay on plastic plates, D epsilon 1 specific mAb led to the binding of IgE but always prevented further binding of anti-D epsilon 1 mAb, anti-human kappa chain mAb or allergen on bound IgE. This was not true when CNBr activated cellulose was used. The influence of the nature of the solid phase disappeared when D epsilon 2 specific mAb were coated on plastic tubes. In this case, the binding of a second mAb with identical or different fine specificity was observed. The best matched pair was E 164 (anti-D epsilon 2) on the solid phase and 6H10 (anti-D epsilon 1) as a tracer. As little as 0.2 UI/ml of IgE could be detected in a 2 hr test.

Dot-immunobinding assay with monoclonal anti-IgE antibodies for the detection and quantitation of human IgE

This paper describes a dot immunobinding assay for determining total human IgE with a tandem of monoclonal anti-IgE antibodies. Minute quantities of monoclonal anti-IgE antibodies were adsorbed on nitrocellulose discs. IgE bound to this solid phase monoclonal anti-IgE antibody was detected by a second monoclonal antibody conjugated with horseradish peroxidase. Using 4-chloro-1-naphthol as a chromogen results in a stable colour reaction that can be semiquantitatively analysed by the naked eye. The colour intensities of the reaction were also analysed by densitometry, yielding a very reproducible quantitation of human serum IgE. Using a serum dilution of 1:50, IgE could be detected in the range of 12.5-2500 U/ml. Using non-diluted serum samples IgE levels between 0.05-50 U/ml were reproducibly measured. Total serum IgE as determined by this dot assay correlated very well with IgE determinations performed by the commercial PRIST assay.

A rapid quantitative capillary tube enzyme immunoassay for human chorionic gonadotropin in urine

A quantitative capillary tube enzyme immunoassay (CTEIA) method for the determination of human urinary chorionic gonadotropin (hCG) has been developed. The method utilizes an antibody-coated capillary tube through which the test fluid is passed and a urease-labelled second antibody in an immunometric format. Any hCG in the test solution is 'captured' by the immobilized antibody which is hybridoma derived and specific for the beta-subunit of hCG. The second hCG-specific antibody, conjugated to the enzyme urease, is used to detect the captured hCG on the internal surface of the capillary tube. The amount of urease bound to the surface is determined by the introduction of a substrate solution containing urea and the pH indicator bromothymol blue. The rate of colour change, from yellow to blue, caused by the release of ammonia from urea by urease, is determined in a spectrophotometer using a cell holder adapted to accommodate capillary tubes. The initial rate of absorbance change is directly proportional to the concentration of hCG in the sample in the range 0-100 mIU/ml. The test can detect concentrations of hCG as low as 10 mIU/ml in a total elapsed time of 5 min.

Quantitative measurement of human immunoglobulin E using monoclonal antibodies to distinct epitopes

Monoclonal antibodies (MAb) which recognize distinct epitopes on human immunoglobulin E have been used to develop two-site sandwich radio- and enzyme-linked immunoassays for the quantitation of human IgE. In the first step, a purified anti-IgE MAb coated to polyvinyl or polystyrene microtiter plates specifically bound the IgE contained in the samples. In the second step, another anti-IgE MAb (either iodinated or conjugated to beta-galactosidase) directed to a different antigenic determinant was used to estimate the amount of bound IgE. This simple method permitted the determination of IgE concentrations of 10 ng/ml and greater in about 3 h. Coefficients of variation on a single day did not exceed 7.5% for IgE levels, covering a wide range of the standard curve. The values obtained on serum samples showed a good correlation with those obtained using the paper radioimmunosorbent test (PRIST).

Monoclonal antibodies to three distinct epitopes on human IgE: their use for determination of allergen-specific IgE

Three different monoclonal antibodies (MAb) against human immunoglobulin E have been obtained which specifically bind to human myeloma and polyclonal IgE. The antibodies showed high avidities for soluble IgE (0.7 X 10(9) to 3.3 X 10(9) M-1). These MAb defined three distinct epitopes on IgE. A mixture of these antibodies in combination with an 125I-labelled anti-mouse Kappa chain MAb has been used to measure allergen-specific IgE. This determination was performed by a solid-phase radioimmunoassay using allergen extracts coated to either chemically activated paper discs or to polyvinyl chloride wells. This method is 4-10 times more sensitive than other previously reported procedures. A similar technique has also been applied to detect individual allergens in immunoblots of allergen extracts.