Isoform-specific monoclonal antibodies against HSP90

Abstract

The purpose of this study was to develop monoclonal antibodies (mAbs) that distinguish between the two isoforms of human 90-kDa heat shock protein (HSP90), i.e., HSP90α and β. Human HSP90α and β isoforms expressed in Escherichia coli were separately used as antigens for developing the mAbs. Twenty-three and ten mAbs were obtained by immunization of mice with HSP90α and β, respectively. Among them, ten and three mAbs specifically recognized HSP90α and β isoforms, respectively, on the criteria of both enzyme-linked immunosorbent and immunoblotting analyses. Immunochemical analysis by use of the mAbs revealed that both of the HSP90 isoforms were present in human cells even under unstressed conditions and that the expression of HSP90α was more strongly induced when the cells were exposed to arsenate. This is the first report of the development of the mAbs discriminating between the two isoforms of HSP90. The mAbs specific for HSP90 isoforms should be useful for the regulational and functional analyses of HSP90 isoforms.