Anti-Rat β-2-Microglobulin (Clone 4C9) - Purified No Carrier Protein (B615-GRP)

Neonatal Fc receptor (FcRn) is a 52 kDa membrane bound heterodimeric glycoprotein composed of a heavy and light chain, with the latter being β-2-microglobulin1. FcRn plays a role in the regulation of IgG catabolism and is located in the endosome where it binds to Fc and IgG. β-2- microglobulin also associates with class I major histocompatibility complex molecules, which are structurally similar to FcRn2. In this capacity, β-2-microglobulin plays an important role in tumor antigen presentation and immune surveillance3. 4C9 was generated by immunizing BALB/c mice with soluble FcRn2. Splenocytes were fused with HL-1 murine myeloma cells. 4C9 is able to bind to β-2-microglobulin as well as FcRn heterodimers in ELISA tests, can immunoprecipitate soluble FcRn heterodimers, and can also stain lipid-linked rat β-2-microglobulin (β2m-DAF), truncated FcRn heavy chain paired with β2m-DAF, and lipid-linked FcRn heavy chain paired with unaltered β-2-microglobulin. 4C9 blocks binding of IgG to FcRn in vitro2 and FcRn blockade has been shown to have a positive effect on IgG-mediated autoimmune diseases1. In support of this, 4C9 induces a transient and dose-dependent increase in the elimination of exogenously administered antimethotrexate IgG in rats4.