title: A new method, distribution-analyzing latex immunoassay (DALIA), to measure specific immunoglobulin G against mite and wheat allergen in human sera.
abstract: A distribution-analyzing latex immunoassay (DALIA), based on the agglutination of latex particles coupled with mite or wheat allergen, was developed to determine allergen-specific IgG in human sera. The immune complex between chemically coupled-allergen latex and specific IgG was agglutinated specifically and efficiently by employing an IgM-type monoclonal second antibody with strong amplification activity. The extent of agglutination was evaluated by determining the relative ratio of volumes (RV) of agglutinates to residual nonagglutinating particles with a particle counter. This method exhibited a high sensitivity (detection limit < or = 5 units/ml) in the determination of allergen-specific IgG, and no influence of inhibitory factors such as competitive antibodies (specific-IgA, -IgM) and nonspecific IgG (< or = 320 mg/ml) was observed. The concentrations of specific IgG against mite allergen in the sera of 130 allergy patients with atopic dermatitis and 52 normal subjects were 22.3 +/- 12.3 and 16.5 +/- 4.2 units/ml, respectively, and the concentrations of specific IgG against wheat allergen in the same two groups were 5.4 +/- 4.2 and 2.1 +/- 2.2 units/ml, respectively. The coefficients of variation of intra- and interassay ranged from 3.4% to 11.2% in both cases. The present method is an excellent homogeneous immunoassay which may be used as a routine assay that can measure 50 samples per hour without prior treatment.
authors.affiliation: Tokyo Research Laboratory, Daiichi Pure Chemicals Co Ltd, Japan.
authors.forename: J Z
authors.initials: JZ
authors.lastname: Xu
authors.forename: M
authors.initials: M
authors.lastname: Matsuo
authors.forename: N
authors.initials: N
authors.lastname: Kamiyama
authors.forename: H
authors.initials: H
authors.lastname: Matsushita
authors.forename: Y
authors.initials: Y
authors.lastname: Sakai
mesh_terms: D000485:Allergens / Q000276:immunology*; D000818:Animals; D000911:Antibodies, Monoclonal; D003876:Dermatitis, Atopic / Q000097:blood* / Q000276:immunology; D006801:Humans; D007118:Immunoassay / Q000379:methods; D007070:Immunoglobulin A / Q000097:blood* / Q000276:immunology; D007074:Immunoglobulin G / Q000097:blood* / Q000276:immunology; D007075:Immunoglobulin M / Q000097:blood* / Q000276:immunology; D007841:Latex Fixation Tests; D008925:Mites / Q000276:immunology*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D012709:Serum Albumin / Q000032:analysis; D014908:Triticum / Q000276:immunology*
chemical_list: D000485:Allergens; D000911:Antibodies, Monoclonal; D007070:Immunoglobulin A; D007074:Immunoglobulin G; D007075:Immunoglobulin M; D012709:Serum Albumin