The cell line was established by Louis Gastinel and Pamela Bjorkman in 1992. Animals were immunized with and twice boosted with soluble neonatal Fc receptor (FcRn) in an adjuvant. Three days before fusion one mouse was boosted with purified FcRn. Spleen cells were fused with HL-1 Friendly myeloma cells (a derivative of P3X63Ag8.653 that is deficient in both hypoxanthine phosphoribosyl transferase [HPRT] and adenine phosphoribosyl transferase [APRT]). The antibody recognizes FcRn heavy chain heterodimers. FcRn is a heterodimer composed of a membrane bound heavy chain attached noncovalently to beta 2-microgloublin. It is structurally similar to class I major histocompatibility (MHC) molecules. The 4C11 antibody and the 1G3 (CRL-2434) antibody recognize two lipid linked forms of the FcRn. These forms are truncated FcRn heavy chain paired with beta 2-microgloublin-DAF (FcRn beta-2 microglobulin DAF) and lipid-linked FcRn paired with unaltered beta 2-microgloublin (FcRn-DAF/beta 2-microgloublin). They also recognize the FcRn-DAF construct. The 2G3 (CRL-2435) antibody fails to recognize the FcRn heterodimer form in which the heavy chain is attached to the lipid anchor (FcRn-DAF/beta 2-microgloublin) and it also fails to recognize the FcRn-DAF construct. Unlike 4C9 (CRL-2437), the monoclonal antibodies IG3 (CRL-2434), 2G3 (CRL-2435) and 4C11 (CRL-2436) do not recognize rat beta 2-microglobulin alone or complexed with FcRn heavy chains. This antibody is used in studies of the MHC class I heavy chain FcRn heterodimers and their interaction with IgG. |
