Immunoglobulin G (IgG) is a member of the immunoglobulin superfamily of glycoproteins that plays a central role in the adaptive immune response.1 It is produced by B cells and later secreted by plasma cells and is the most abundant circulating antibody in human and mouse serum.1,2,3 IgG consists of two heavy chains of approximately 50 kDa each and two light chains of approximately 25 kDa each.1 The heavy chains are linked together by disulfide bonds to form an Fc region and also combine with the light chains to form the Fab region, which mediate receptor and antigen binding, respectively.4 IgG is produced following IgM class-switching in response to infection and is involved in numerous humoral host defense responses, including antibody-dependent cell-mediated cytotoxicity (ADCC), toxin neutralization, and pathogen opsonization.2 IgG exists as four isotypes in humans, IgG1, IgG2, IgG3, and IgG4, each of which has a distinct effector function. IgG4 is the least predominant IgG isotype in human serum and contains a serine at position 228 in its hinge region that facilitates Fab arm exchange, resulting in two antigen-binding sites and a functionally monovalent antibody.5 Increased serum levels of IgG4 positively correlate with desensitization and allergen tolerance in beekeepers, laboratory workers chronically exposed to rodent allergens, and individuals undergoing allergy immunotherapy for severe allergies to cats, dust mites, birch pollen, and wasps. Cayman’s IgG4 Fc (human) Rabbit Monoclonal Antibody - Biotinylated (RM217) can be used for ELISA. The antibody recognizes the Fc region of IgG4 from human samples.WARNING This product is not for human or veterinary use.
