Structural Basis for the Shared Neutralization Mechanism of Three Classes of Human Papillomavirus Type 58 Antibodies with Disparate Modes of Binding

Abstract

Human papillomavirus type 58 (HPV58) is associated with cervical cancer and poses a significant health burden worldwide. Although the commercial 9-valent HPV vaccine covers HPV58, the structural and molecular-level neutralization sites of the HPV58 complete virion are not fully understood. Here, we report the high-resolution (∼3.5 Å) structure of the complete HPV58 pseudovirus (PsV58) using cryo-electron microscopy (cryo-EM). Three representative neutralizing monoclonal antibodies (nAbs 5G9, 2H3 and A4B4) were selected through clustering from a nAb panel against HPV58. Bypassing the steric hindrance and symmetry-mismatch in the HPV Fab-capsid immune-complex, we present three different neutralizing epitopes in the PsV58, and show that, despite differences in binding, these nAbs share a common neutralization mechanism. These results offer insight into HPV58 genotype specificity and broaden our understanding of HPV58 neutralization sites for antiviral research. IMPORTANCE Cervical cancer primarily results from persistent infection with high-risk types of human papillomavirus (HPV). HPV type 58 (HPV58) is an important causative agent, especially within Asia. Despite this, we still have limited data pertaining to the structural and neutralizing epitopes of HPV58, and this encumbers our in-depth understanding of the virus mode of infection. Here, we show that representative nAbs (5G9, 10B11, 2H3, 5H2 and A4B4) from three different groups share a common neutralization mechanism that appears to prohibit the virus from associating with the extracellular matrix and cell surface. Furthermore, we identify that the nAbs engage via three different binding patterns: top-center binding (5G9 and 10B11), top-fringe binding (2H3 and 5H2), and fringe binding (A4B4). Our work shows that, despite differences in the pattern in binding, nAbs against HPV58 share a common neutralization mechanism. These results provide new insight into the understanding of HPV58 infection.

Implications of Persistent HPV52 and HPV58 Positivity for the Management of Cervical Lesions

“…This is consistent with the Kaidar–Person study, which found that HPV58 has a 1.8-fold higher association with invasive cervical cancer than HPV52 ( 15 ). We can consider HPV type 58 an important pathogen, especially in Asia ( 16 ). Therefore, in patients who are positive for HPV type 58, especially those with persistent infection despite normal TCT results, attention needs to be paid and the indications for colposcopy may be relaxed as appropriate.…”

Cryo EM Analysis Reveals Inherent Flexibility of Authentic Murine Papillomavirus Capsids

“…Previously, reconstructions of papillomaviruses with full icosahedral symmetry imposed have produced maps limited to modest resolution; however, recently subparticle reconstruction approaches have been successfully used to obtain high resolution [ 16 , 17 , 36 ]. Consistent with this finding, we found that for the native papillomavirus the icosahedrally enforced reconstruction did not advance beyond 4.4 Å resolution.…”

“…The complete T = 7d icosahedral papillomavirus capsid has previously been visualized to modest resolution by cryogenic electron microscopy (cryo EM) with icosahedral symmetry imposed during the reconstruction [ 4 , 8 , 9 , 10 , 11 , 12 , 13 , 14 ]. No structural studies of papillomavirus capsids with 60-fold icosahedral symmetry imposed have exceeded 4.1–4.4 Å resolution [ 13 , 14 , 15 , 16 ]. The structure of HPV16 QV published by Guan et al at 4.3 Å showed there is likely inherent flexibility of the papillomavirus capsid as evidenced by the variability in capsid resolution, and differing capsid diameters [ 13 ].…”

A humanized anti-human adenovirus 55 monoclonal antibody with good neutralization ability

“…The viral supernatants were collected by centrifugation for purification by calcium chloride gradient centrifugation ( 28 ). The 50% tissue culture infective dose (TCID50) was calculated to determine adenovirus titers according to the classical Reed-Muench method ( 29 ).…”