Data sheet
| Application | IgG4 Screen 88 Food Antigens ELISA Test Kit has been designed for the detection and the quantitative determination of specific IgG4 antibodies against food antigens in serum and plasma. |
| Background | Incompatibility reactions against food may cause various symptoms in the human organism and this disturbance is manifested in the immune system by the formation of specific IgE, IgG or IgG4 antibodies. Statistics show that 60% of the population suffer from intolerances against at least one foodstuff, which may cause clinical symptoms or enhance them. Hints may be various and reach from skin irritations over digestive disorders up to migraine. With the diagnostic findings of unspecific discomfort, allergies or intolerances against food should be clarified. The theoretical basis for the determination of specific IgG or IgG4 for the diagnosis of food intolerances depends on the observation that some subclasses of IgG (mainly IgG4) are connected to the in vitro degranulation of basophilic cells and mastocytes and the activation of the complement cascade. It was also observed that high concentrations of circulating IgG were measured in atopic persons. Already early surveys showed that in persons with inflammatory reactions against food IgG but not IgE was detected. Significantly enhanced IgG and IgG4 titers were also found in patients with food intolerances. Skin tests are relatively poorly correlated to food allergies and are only significant in the presence of IgE related reactions. As additional diagnostic tools provocation and elimination diets are applied. These methods depend strongly on the motivation and compliance of the patient. Due to these constraints nowadays serological determinations of antibodies against various food panels are applied increasingly. The two reactions related with the immune system differ insofar as the IgE associated food allergy occurs within the next hour following the food intake, while IgG/IgG4 intolerances show a delayed reaction of 24 to 120 hours and persistent symptoms may arise. |
| Assay principle | IgG4 Screen 88 Food Antigens ELISA test kit is based on the principle of the enzyme immunoassay (EIA). 88 different food antigens and 8x reference antigens (egg white) for standards and controls are bound on the surface of the microtiter strips. Diluted patient serum or ready-to-use standards and controls are pipetted into the wells of the microtiter plate. A binding between the IgG4 antibodies of the serum and the immobilized antigens takes place. After a one hour incubation at 37°C, the plate is rinsed with diluted wash solution, in order to remove unbound material. Then ready-to-use anti-human-IgG4-AP conjugate is added and incubated for 30 minutes at 37°C. After a further washing step, the substrate (PNPP) solution is pipetted and incubated for 60 minutes at 37°C, inducing the development of a yellow dye in the wells. The color development is terminated by the addition of a stop solution. The resulting dye is measured spectrophotometrically at the wavelength of 405 nm. The concentration of the IgG4 antibodies is directly proportional to the intensity of the color |
More info
Microtiter Plate 1 microtiter plate, coated with 88 food antigens (see distribution scheme) and 8x reference antigen (1. strip, color coded violet). Ready-to-use.
Standards A-F 6 x 0.5 mL, human plasma diluted with PBS/BSA, with 0.35, 0.70, 3.5, 17.5, 50 and 100 U/mL of IgG antibodies against egg white (f1). Addition of 0.05% sodium azide. Ready-to-use.
Weak Positive Control 0.5 mL, human plasma diluted with PBS/BSA, including low concentrations of IgG antibodies. Addition of 0.05% sodium azide. Ready-to-use.
Strong Positive Control 0.5 mL, human plasma diluted with PBS/BSA, including high concentrations of IgG antibodies. Addition of 0.05% sodium azide. Ready-to-use.
Anti-human-IgG4 Enzyme Conjugate 15 mL, mouse-a-human-IgG4-AP, in proteinaceous buffer solution. Addition of 0.01% methyl
isothiazolone, 0.01% bromonitrodioxane and 5 mg/L ProclinTM. Ready-to-use.
Substrate 15 mL, PNPP (Paranitrophenylphosphate). Ready-to-use.
Stop Solution 15 mL, 1 M sodium hydroxide. Ready-to-use.
Sample Diluent 40 mL, PBS/BSA buffer. Addition of 0.05% sodium azide. Ready-to-use.
Washing Buffer 60 mL, PBS + Tween 20, 10x concentrate. Final concentration: dilute 1+9 with deionized water. If during the cold storage crystals precipitate, the concentrate should be warmed up at 37°C for 15 minutes.
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