From modular
vaccine production to
protein assembly on nanoparticles, the SpyCatcher/SpyTag system provides a convenient plug-and-display procedure. Here, we established a general-purpose immunoaffinity chromatography (IAC) method for SpyTagged
proteins (Spy&IAC). SpyTags are displayed on the surface of nanoparticles to induce high-affinity
monoclonal antibodies, allowing the specific capture of the target
protein. Taking the key core antigenic regions of two coronaviruses that are currently more threatened in the field of human and
animal diseases, the nucleocapsid (N)
protein of SARS-CoV-2 and the COE
protein of porcine epidemic diarrhea virus (PEDV) as model
proteins, a purification model with SpyTag at the N-terminal or C-terminal expressed in E. coli or mammalian cells was constructed. After the efficient elution of Spy&IAC, the final yield of several
proteins is about 3.5-15 mg/L culture, and the
protein purity is above 90 %. Purification also preserves the assembly function and immunogenicity of the
protein to support subsequent modular assembly and immunization programs. This strategy provides a general tool for the efficient purification of SpyTagged
proteins from different expression sources and different tag positions, enabling the production of modular
vaccines at lower cost and in a shorter time, which will prepare the public health field for potential pandemic threats.