HUMAN IgG SUBCLASS KITS: NEPHELOMETRIC METHODOLOGY

Human IgG Subclasses nephelometric BNA kit

CAT# RDI-M1620clb PRICE:$ 760.00/kit $700.00/kit 10 or more

Introduction:

Human IgG consists of four subclasses, which show more than 95% homology in the amino acid sequence of the C-domains of their heavy chains. The IgG subclasses show differences in effector functions like antigen recognition, complement activation and cell surface Fc receptor binding. Antibodies against viral capsid proteins were found to belong predominantly to the IgG1 and IgG3 subclasses, whereas IgG2 is the predominant subclass in immune responses against polysaccharides. The IgG4 subclass, although representing a minor fraction in the total serum IgG, has received attention because it is highly responsive to repeated challenges with environmental antigens. The interest in the quantification of human IgG subclasses is supported by a recommendation from a WHO/IUIS working group which states: "Measurement of total levels of IgG subclasses is essential in patients with increased susceptibility to bacterial infections when the total IgG level is within or slightly below the normal range".

Recently Shield et al showed that also hypergammaglobulinaemia does not exclude the presence of an IgG subclass deficiency. The concentrations of IgG subclasses in serum of children variedwidely with age. Infants and young children have lower subclass concentrations than adolescents and adults. IgG1 and IgG3 levels rise more rapidly with age than IgG2 and IgG4 concentrations. To determine an IgG subclass deficiency, it is essential to have reliable reference ranges for the individual IgG subclasses.

This IgG subclasses kit is intended for fast, reproducible and specific (high correlation to radial immunodiffusion technique) measurement of human IgG subclasses in serum and other biological fluids on the Behring Nephelometer Analyzer (BNA).

Contents

-anti-human IgG1, IgG2, IgG3, IgG4 antisera (25 tests)

-anti-human IgG antiserum

-standards and controls

-superfix

-reference values for human IgG subclasses.

Characteristics

IgG1 IgG2 IgG3 IgG4

-sensitivity (mg/l) 10 5 3 4

-correlation with RID (%) 93 95 91 98

-intra-assay variation (%) 2.0 6.4 3.1 3.0

-inter-assay variation (%) 4.6 7.4 6.1 6.7

-total assay incubation time(min) 6 6 6 12

Applications

-Deficiencies of IgG subclass concentrations are in indication of a disturbed immune response.

-The association of selective IgG2 and/or IgG3 subclass deficiency with increased susceptibility to viral or bacterial infections is amply documented.

-Abnormalities in IgG subclass concentrations have been observed in patients with allergy, autoimmune diseases, neurological disorders,dialysis and during HIV-infections.

References

-2nd IUIS/WHO report (1988) Clin.Exp.Immunol. 74:494

-Hamilton,R.C. (1987) Clin.Chem. 33: 1707

-Jefferis,R. et al (1990) Clin.Exp.Immunol. 81:357

-Shackelford,P.G. et al (1990) J.Pediatric.116:529

-Shakib,F.(Ed) Monograph in Allergy 19 (1986) Karger A.G.

-Shakib,F.(Ed) The human IgG subclass (1990) Pergamon Press

-Shield,J.P.H. et all (1992) The Lancet 340: 448

-Vlug,A. et al (1989) Eur.Clin. Lab. 8:26

Assay Procedure

The quantitative determination of IgG subclasses in biological fluids is based on the specific reaction of the human IgG subclass to be determined with highly avid anti-IgG subclass antisera. The generated immune complexes can be determined by meassurement of the scattered light. The measurement are evaluated by using a standard curve prepared with the aid of a serially diluted standard. The obtained referebce curves are stored and can be reactivated. A control serum is assayed to check the validity of the reference curves and the precision of the IgG subclass determination. Non-specific light scattering, occasionally observed in turbid samples or in low dilution of patients sera (needed to measure trace concentrations) can be detected by running a separate assay with the IgG subclass blank reagent on the IgG4 reference curve.

Assay conditions for the Behring Nephelometer Analyzer (BNA):(batch specific setting see actual insert)