IgG2b is a subtype of immunoglobulin G that plays a significant role in the adaptive immune response. It is produced by B cells in response to antigens and is the third most abundant IgG subtype in serum. Composed of two heavy chains and two light chains, IgG2b is involved in several immune functions, including opsonization, complement activation, and antibody-dependent cell-mediated cytotoxicity. Additionally, it regulates immune responses by activating T cells and inhibiting B cell activation. IgG2b is widely utilized in research and diagnostic applications, such as ELISA, Western blotting, and immunohistochemistry, as well as in therapeutic contexts like immunotherapy and vaccine development. Isotype controls using IgG2b are essential for ensuring specificity in experimental assays, helping to differentiate between specific antibody binding and non-specific background signals.