IgG / IgG4

Specific IgG or IgG4

Enzyme Immuno Assay for the quantitative determination of specific IgG or specific IgG4 antibodies in human Serum or Plasma

Background

Allergen specific antibodies of the type Immunoglobulin G (IgG) are responsible for the intermediation of allergic reactions of the cytotoxic as well as the immune complex type and for this play an important role in the extended allergy diagnostic. Antibodies, also known as immunoglobulins (Ig), play an important role in the humoral immune response to extrinsic, infectious agents. Furthermore Ig and in particular Ig of the IgG type can be generated to normally harmless antigens, e.g. inhalation antigens or food antigens. A typical disease represents the exogenic allergic alveolities (EAA), which can be caused by occupational exposition of substances in the air. Involved are normally moldy- and bacterial components but also excrements, flours or chemical components which are inhaled as dusts or aerosols during work. Farmer´s lung is caused by Thermophile Actinomycetes in moldy hay. Farmer´s lung, Malt- and Paper worker´s lung as well as Pigeon Breeder´s disease are well known to represent such diseases. Also fish flour, saw dust, dust from furs and in addition chemical components can cause alveolitis. Through the generation of antigen specific IgG antibodies it can come to an allergic reaction of type 3 (immune complex type) in the alveolus. Initially an acute inflammation arises, which can get chronic and in the worst case can end in a pulmonary fibrosis.

Immunoglobulins (Ig) of the IgG4-subclass play an important role in the humoral immune reaction during immunotherapy e.g. for insect venoms (bee and wasp). Increase of the specific IgG4 concentration indicates a positive response to the immunotherapy. Specific IgG4 has been reported to compete with specific IgE for binding to the corresponding antigen (allergen). Therefore specific IgG4 is thought to reduce the capability of degranulation of the mast cells and the basophile granulocytes.

PRINCIPLE

IgG: This sIgG test is based on ELISA (Enzyme Linked Immuno Sorbent Assay) technology. It detects specific IgG of patients with Type III allergies (exogenic allergic alveolities). Diluted serum or plasma samples of patients are incubated in antigen coated microwell strips. During incubation specific IgG binds to antigens on the surface of the microwell cavity. After application of anti-human-IgG-alkaline-phosphatase (AP) conjugate a complex of antigen/IgG/anti-IgG-AP will form. After application of p-nitrophenylen-phosphate (pNPP) solution the amount of antibody-enzyme complex is detected. After addition of sodium hydroxide (NaOH) the extinction of the colored reaction product which is proportional to the amount of specific IgG of the sample, can be measured at 405 nm (reference wave length 620 nm). Calibrators of know IgG concentrations form a calibration curve in which the IgG concentrations of the samples can be determined. (Download: IFU “10100PG”)

Download Instruction for Use

IgG4: The test system works on the basis of an Enzyme Linked Immuno Sorbent Assay (ELISA) and tests antigen- (allergen-) specific IgG4-antibodies in serum or plasma from patients. Diluted human serum or plasma is incubated in antigen (allergen) coated strips. Specific IgG4-antibodies react with their corresponding allergen. Unbound antibodies are removed by washing. The allergen-specific bound antibodies are recognized by a second anti-human IgG4-antibody conjugated to horseradish peroxidase (HRP). The presence of bound IgG4/anti-IgG4/HRP-complexes is enzymatically detected by incubation with the substrate TMB solution resulting in the development of a blue color. After stopping the test with acid the color changes into yellow. The optical density of the yellow color is measured spectrophotometrically at 450 nm (reference wave length 620 nm). Within the measuring range the concentration of allergen specific IgG4-antibody is directly proportional to the color intensity. Calibrators with defined concentrations of IgG4 are assayed simultaneously with the patient samples to generate a calibration curve. Unknown IgG4 concentrations of the test samples are calculated from this curve. (Download: IFU “10104PG”)

SYSTEMS

For the manual performance of specific IgG or IgG4 our ALLERG-O-SYSTEM is available. (Download: Flyer ALLERG-O SYSTEM)

AVAILABLE ANTIGENS

For more informations, please send us an email