Phage Display-Based Discovery of HPV Capsomere-Specific Antibodies for HPV Process Characterization

Human papillomaviruses (HPV) are a diverse group of viruses that primarily infect squamous epithelial cells, often leading to proliferative lesions and various cancers. The HPV capsid is formed from the coassembly of two major capsid proteins, L1 and L2. Notably, the L1 protein can self-assemble into virus-like particles (VLPs) that exhibit structural and immunological similarities to the native virus capsid. The assembly of L1 proteins into VLPs involves the formation of the critical repeating pentamer subunits known as capsomeres. However, due to high structural similarities, there are no antibodies that can distinguish between capsomeres and VLPs, making it challenging to work with capsomeres. In this study, we generated and characterized capsomere-specific monoclonal antibodies (mAbs) to probe HPV manufacturing process. We prepared high-purity Type16 (T16) capsomeres, and used phage display technology to developed mAbs with high affinity for T16 capsomeres. Using immunoassays and biophysical analyses, we demonstrated that these antibodies bind to conformational epitopes on T16 capsomeres but not T16 VLPs. Furthermore, we established an enzyme-linked immunosorbent assay (ELISA) using one of these antibodies to quantify capsomere in cell lysates. Our findings demonstrate that these capsomere-specific antibodies are valuable tools for probing HPV process intermediates in order to optimized process development.