Generation of a recombinant GST-Tau antigen for indirect ELISA in evaluating Alzheimer`s disease vaccines

BackgroundAlzheimers disease is a progressive neurodegenerative disorder. Immunotherapy targeting A{beta} and Tau proteins is a promising strategy, and accurate detection of anti-A{beta} or anti-Tau antibodies is key to evaluating vaccine efficacy. Indirect ELISA is a sensitive method requiring high-quality coating antigens. MethodologyA recombinant Tau antigen fused to glutathione S-transferase (GST) was designed as an ELISA coating antigen. The Tau gene was cloned into the pGEX-6p-1 vector and expressed in Escherichia coli BL21 cells. Protein expression was induced with 1 mmol/L isopropyl-{beta}-D-thiogalactoside (IPTG), and the GST-Tau fusion protein was identified by Western blot using anti-Tau and anti-GST antibodies. The protein was solubilized with 3 mol/L urea and purified via glutathione affinity chromatography. Purity was confirmed by densitometry and the optimal coating concentration for ELISA was determined to be 2 g/mL. ResultsA protocol was established to produce GST-Tau with adequate purity and yield for ELISA applications. The recombinant antigen retained immunogenic epitopes, recognized by anti-Tau antibodies. The standardized ELISA enabled sensitive detection of anti-Tau antibodies. ConclusionsA robust method was developed to produce and optimize GST-Tau as a coating antigen for indirect ELISA. This approach facilitates reliable quantification of anti-Tau antibodies to evaluate Alzheimers vaccine candidates.