Each genotype had at least one variant that displayed a 4-fold reduced neutralizing antibody sensitivity against at least one MAb, demonstrating that naturally occurring variation can affect one or more functional antigenic determinants around the HPV capsid

Each genotype had at least one variant that displayed a 4-fold reduced neutralizing antibody sensitivity against at least one MAb, demonstrating that naturally occurring variation can affect one or more functional antigenic determinants around the HPV capsid. The HPV capsid is an icosahedral lattice comprising 72 pentamers of the major capsid protein (L1) and the associated minor capsid protein (L2). We investigated the potential impact of this genome variation around the capsid antigenicity of lineage and sublineage variants of seven vaccine-relevant, oncogenic HPV genotypes by using a large panel of monoclonal antibodies (MAbs) raised against the L1 proteins of lineage A antigens. Each genotype had at least one variant that displayed a 4-fold HSP70-IN-1 reduced neutralizing antibody sensitivity against at least one MAb, demonstrating that naturally occurring variation can affect one or more functional antigenic determinants around the HPV capsid. For HPV16, HPV18, HPV31, and HPV45, the overall impact was of a low magnitude. For HPV33 (sublineages A2 and A3 and lineages B and C), HPV52 (lineage D), and HPV58 (lineage C), however, variant residues in the indicated lineages and sublineages reduced their sensitivity to neutralization by all MAbs by up to 1 1,000-fold, suggesting the presence of key antigenic determinants on the surface of these capsids. These determinants were resolved further by site-directed mutagenesis. These data improve our understanding of the impact of naturally occurring variation around the antigenicity of the HPV capsid of vaccine-relevant oncogenic HPV genotypes. IMPORTANCE Human papillomavirus (HPV) is the causative agent of cervical and some other epithelial cancers. HPV vaccines generate functional (neutralizing) antibodies that target the virus particles (or capsids) of the most common HPV cancer-causing genotypes. HSP70-IN-1 Each genotype comprises variant forms that have arisen over millennia and which include changes within the capsid proteins. In this study, we explored the potential for these naturally occurring variant capsids to impact recognition by neutralizing monoclonal antibodies. All genotypes included at least one variant form that HSP70-IN-1 exhibited reduced recognition by at least one antibody, with some genotypes affected more than others. These data highlight the impact of naturally occurring variation around the structure of the HPV capsid proteins of vaccine-relevant oncogenic HPV genotypes. KEYWORDS: human papillomavirus, variant, lineage, antigenicity, neutralization, monoclonal antibodies INTRODUCTION Human papillomavirus (HPV) is the causative agent of cervical and other epithelial cancers and accounts for >600,000 cases globally per annum (1,C3). Small double-stranded DNA HSP70-IN-1 (dsDNA) genomes typically exhibit a low evolutionary rate (4), although distinct HPV genotypes have arisen over time (5). Genotypes from the genus contribute to the development of cervical and other cancers (2), with HPV16 conferring the highest relative risk. Whole-genome sequence analysis has led to the delineation of distinct HPV lineages and sublineages that exhibit both geographical bias in their distribution and differential disease risk (5,C7). Efforts are also underway to understand the evolution of HPV variants from their prehistoric origins (6, 7). For example, HPV16 (6) and HPV58 (7) non-A lineages (B/C/D) are estimated to have split from their respective lineage A viruses approximately 400 to 600 thousand years ago (kya), followed by the further resolution of lineages B, C, and D by approximately 100 to 200 kya, coincident with the evolution and global migration of ancient Rabbit Polyclonal to C1QB hominins (6, 7). The HPV capsid is an icosahedral lattice comprising 72 pentamers of the major capsid protein (L1) and includes the asymmetrical and/or stochastic distribution of the minor capsid protein (L2) (8, 9). Each L1 monomer consists of a core of -strands and -helices which support the five surface-exposed loop domains designated BC, DE, EF, FG, and HI. Type-specific neutralizing antibodies raised against the L1 capsid protein predominantly target these surface-exposed loops (10). The binding of a number of monoclonal antibodies (MAbs) to the capsid surface has been resolved to ca. 3?? using HSP70-IN-1 pentameric crystals or ca. 10?? by cryo-electron microscopy (11,C16) and reveals the complexity of these interactions, including antibody footprints spanning multiple loops and adjacent monomers within a pentamer. Neutralizing antibodies directed against the L1 capsid can passively safeguard in preclinical challenge models, leading to the development of highly efficacious L1 capsid-based prophylactic vaccines (17). Bivalent (Cervarix) and quadrivalent (Gardasil) vaccines target the most prevalent oncogenic genotypes (HPV16 and HPV18), while the nonavalent (Gardasil 9) vaccine targets five additional oncogenic genotypes (HPV31, HPV33, HPV45, HPV52, and HPV58). Quadrivalent and nonavalent vaccines also target nononcogenic genotypes, HPV6 and HPV11, which can cause genital.