Specific antiserum staining of two‐dimensional electrophoretic patterns of human plasma proteins immobilized on nitrocellulose

Abstract

AbstractHuman plasma proteins separated by high‐resolution two‐dimensional electrophoresis have been electrophoretically transferred to sheets of nitrocellulose using a modification of the method of Towbin, Staehelin, and Gordon [8]. Although the proteins have been denatured in sodium dodecyl sulfate and separated into subunits, the nitrocellulose‐bound molecules still react with appropriate specific antisera even after storage of the transfer in air at room temperature for 5 months. Of 25 proteins whose location in the pattern had been previously determined, 24 are specifically revealed on transfers of whole plasma patterns by appropriate antiserum. In addition, 6 previously unidentified proteins (prothrombin, C1s, C4γ, C1s inhibitor, Ig J‐chain, and a1AP glycoprotein) have been identified in the pattern for the first time using the transfer technique. It therefore seems likely that a large majority of proteins (> 96 % in this study) retain sufficient conformation throughout the analytical procedure (or can regain it easily afterwards) to be recognized immunologically. The transfer technique thus constitutes a generally useful immunological “third‐dimension” in the high‐resolution separation of proteins. Of three monoclonal antibodies similarly tested, none could detect antigen transferred to nitrocellulose from a two‐dimensional gel, while each bound specifically to the appropriate antigen absorbed in native form to the nitrocellulose.