Production and characterization of monoclonal antibodies recognising defined regions of the human oestrogen receptor.

Mouse monoclonal antibodies were raised against the N-terminal (amino acids 151-165) and the very C-terminal (amino acids 578-595) regions of the human oestrogen receptor (hER). These antibodies recognise the hER by enzyme-linked immunosorbent assay, immunocytochemistry, immunoblotting, immunoprecipitation and gel retardation assays. The presence of hER is used prognostically in human breast cancer. We have tested the reactivity of our monoclonal antibodies on breast cancer sections, comparing with the commonly used Abbott rat monoclonal antibody H222. These studies show that the two monoclonal antibodies described here are highly versatile and will be useful tools for in vivo and in vitro studies of hER function. Furthermore, we show that the corresponding epitopes can be used as molecular "tags" for heterologous proteins and offer a powerful means of purifying and/or characterizing over-produced fusion proteins containing these regions.