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 p roteins such as mouse monoclonal antibody to the Alzheimer precursor protei n A4 (APP(695)) and cell line TE671 acetylcholine receptor (AChR(TE671)) in to a stable reagent, after its immobilization on microtitration plates. The remarkable property of the dry immobilized proteins are their stability un der prolonged exposure to temperatures as high as 50 degrees C. Using the A ChR(TE671), the proposed method was applied for the measurement of anti-ACh R autoantibodies in Myasthenia gravis by means of an enzyme-linked immunoso rbent assay (ELISA). The test was shown to be specific and able to detect a nti-AChR autoantibodies at concentrations as low as 3 nM. Using the same AC hR(TE671) as antigen, the results of examination of 34 serum samples for de tection of anti-AChR autoantibodies by ELISA were compared with those of th e conventional radioimmunoprecipitation assay (RIA). It was concluded that ELISA is another useful method for the diagnosis of M. gravis. The ELISA me thod offers a rapid, simple, safe and inexpensive means for mass screening of M. gravis. (C) 1999 Elsevier Science B.V. All rights reserved.