Total IgE ELISA
Total IgE ELISA
The Total IgE ELISA Test Kit has been designed for the detection and the quantitative determination of total Immunoglobulin E antibodies (IgE) in serum and plasma.
The existence of IgE in man as a unique class of immunoglobulins, which are important in the mediation of the allergic response, has been known for over twenty years. The mechanism of action involves an initial antigenic stimulation of immunocompetent B lymphocytes by a specific antigen, a process which induces the lymphocyte to respond by producing specific antibody of several classes.
One class, reaginic or IgE antibody, becomes partially bound via its Fc portion to receptors on the surface of mast cells and basophils. Upon further stimulation by specific allergens, these cell- bound IgE molecules bind via their Fab portion to the allergen. This combination triggers the mast cells and basophils to release various vasoactive amines into the blood and the surrounding tissue. These substances cause smooth muscle constriction and lead ultimately to allergic conditions such as wheal and flare reactions, hives, dermatitis, rhinitis, hay fever, asthma and anaphylactic shock.
IgE determinations are most valuable in the diagnostic assessment of patients with established or suspected allergic disease. In normal subjects, IgE values are related to age, with normal values peaking around 10 - 14 years. Infants and children with family history of atopic allergy are at increased risk of developing disease and constitute a prime population for screening. Studies have shown that conditions such as asthma, rhinitis, eczema, urticaria, dermatitis and some parasitic infections lead to increased IgE levels. Asthma, hay fever and atopic eczema patients may produce levels 3 - 10 times those of normal patients.
PRINCIPLE OF THE TEST
The Total IgE ELISA is based on the principle of the enzyme immunoassay (EIA). A monoclonal mouse anti-human IgE antibody is bound on the surface of the microtiter strips. Undiluted patient serum or ready-to-use standards are pipetted into the wells of the microtiter plate together with anti-human-IgE-peroxidase conjugate. A sandwich complex between the serum IgE and the two antibodies develops. After a 30 minutes ́ incubation at room temperature, the plate is rinsed with diluted wash solution, in order to remove unbound material. Then the substrate (TMB) solution is pipetted and incubated for 15 minutes, inducing the development of a blue dye in the wells. The colour development is terminated by the addition of a stop solution, which changes the colour from blue to yellow. The resulting dye is measured spectrophotometrically at the wavelength of 450 nm. The concentration of the IgE antibodies is directly proportional to the intensity of the colour.