Sheep Human IgG4 (subclass specific) Antibody

Precipitating polyclonal sheep antisera to human IgG4, subclass specific. In precipitating techniques as immunoelectrophoresis and double radial immunodiffusion to identify and measure the concentration of IgG4 subclass in serum or other body fluids. Human IgG constitutes about 75% of the total Immunoglobulins in the serum of normal adults. It consists of four subclasses which are distinguished in isotypic heterogeneity of the gamma chains, and in physicochemical, biological and effector properties. The term subclass designates the high degree of homology in amino acid sequences and antigenic structure. In normal adult serum, the approximate percentage composition of IgG with respect to its subclasses is: IgG1: 65%, IgG2: 23%, IgG3: 8% and IgG4: 4%. All four subclasses appear in both isotypes of the light chain. Normal serum thus contains eight different molecular forms of IgG, the absolute and relative distribution being genetically controlled and resulting from individual responses to the antigenicity of the environment. Antigenic determinants carrying isotypic subclass specificity can be situated on any of the three structurally very similar sub-regions o the gamma chains, known as domains. In IgG, some antigenic deter- minants are shared by two or three subclasses, but not by all four. Consequently, antibodies to such determinants will not be strictly subclass-specific. For the identification of human IgG4 in cells and tissues by immunofluorescence or immunocytochemical peroxidase techniques, or in body fluids by ELISA and Western blotting type procedures, Biorbyt monoclonal antibody reagents to the individual subclasses are available.