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

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.