Monoclonal antibody against human growth hormone receptor

GHR shows a high degree of homology with the prolactin receptor and with th e other receptors that belong to the hemopoietic receptor superfamily, This paper describes a monoclonal antibody (MAb) (2B4B6) specific for both the extracellular domain of human GHR and human growth hormone (GH) binding pro tein. Mice were immunized against a seven-aminoacid peptide sequence screen ed by FASTA (sequence similarity search served by Genome-Net) from the Euro pean Bioinformatics Institute to exclude the existence of human membrane pr oteins with significant sequence homology, MAbs were screened against the p eptide sequence and 2B4B6 was selected for its capability to recognize the full-length hGHBP. As evaluated by both enzyme-linked immunoadsorbent assay (ELISA) and FAGS analysis, this MAb seems to recognize and bind to a hGHR positive cell line, IM-9, as well as a murine cell line, BaF3 (8/6), transf ected with a chimeric construct, hGHR/hG-CSFR and expressing hGHR on the ce ll membrane, Studies investigating the biological effects of this MAb showe d that anti-hGHR mediated inhibition of cell proliferation was not due to c ompetition with GH binding but rather to prevention of receptor dimerizatio n, Because of its specificity, this MAb may be usefully applied in situatio ns in which GHR and receptors with a high degree of homology, such as PRLR (prolactin receptor), are expressed simultaneously, as occurs in the immune system.