Purification and characterization of kyasanur forest disease virus EDIII domain of major envelope glycoprotein

Current research efforts are underway to create novel approaches for the efficient diagnosis, monitoring, and mitigation of Kyasanur Forest Disease Virus (KFDV) infections. Flavivirus subunit-based vaccines based on envelope glycoprotein EDIII are now in preclinical and clinical research stages. Efficient purification and isolation methods for surface immunogenic viral antigens, including the recombinant envelope immunoglobulin-like domain III (rEDIII) protein, are crucial for the production and manufacturing of promising vaccine candidates that have been extensively assessed in previous literature. Here, we describe a method for high-yield expression, purification, and refolding of a KFDV rEDIII protein from a bacterial expression system. The KFDV rEDIII protein is extracted from the inclusion bodies in urea denaturing buffer followed by nickel-nitrilotriacetic acid (Ni-NTA) affinity chromatography. The purified, denatured KFDV rEDIII protein was subsequently refolded using a step-wise gradient urea dilution via the dialysis method. The circular dichroism and Fourier transform infrared spectroscopy analysis confirms that the refolded KFDV rEDIII maintains the native secondary conformation majorly containing β-strands. Our study provides valuable insights into the design and expression strategies of rEDIII as a novel subunit vaccine candidate against KFDV.