Protection of immunoreactivity of dry immobilized proteins on microtitration plates in ELISA: application for detection of autoantibodies in myasthenia gravis.

Abstract We show the ability of the BSA-trehalose film to convert normally fragile proteins such as mouse monoclonal antibody to the Alzheimer precursor protein A4 (APP 695 ) and cell line TE671 acetylcholine receptor (AChR TE671 ) into a stable reagent, after its immobilization on microtitration plates. The remarkable property of the dry immobilized proteins are their stability under prolonged exposure to temperatures as high as 50°C. Using the AChR TE671 , the proposed method was applied for the measurement of anti-AChR autoantibodies in Myasthenia gravis by means of an enzyme-linked immunosorbent assay (ELISA). The test was shown to be specific and able to detect anti-AChR autoantibodies at concentrations as low as 3 nM. Using the same AChR TE671 as antigen, the results of examination of 34 serum samples for detection of anti-AChR autoantibodies by ELISA were compared with those of the conventional radioimmunoprecipitation assay (RIA). It was concluded that ELISA is another useful method for the diagnosis of M. gravis . The ELISA method offers a rapid, simple, safe and inexpensive means for mass screening of M. gravis.