Cervical HPV infection and related diseases among 149,559 women in Fujian: an epidemiological study from 2018 to 2023.

Objectives: To comprehensively analyze the epidemiological features of human papillomavirus (HPV) and HPV-related cervical diseases in females aged 35-64 years. Methods: A total of 149,559 samples of exfoliated cervical cells screened for HPV and related cervical lesions from January 2018 to December 2023 were enrolled. The prevalence of 15 high-risk and 6 low-risk HPV genotypes were detected, and the cervical cytology were analyzed. The impact of single and multiple HPV infections was characterized, and the effect of age was studied. Results: The cervix cytology was normal in 86.60% of the females, while 7.13% of the females were diagnosed with cervix inflammation, 0.60% with ASC-US, 0.22% with ASC-H, 0.72% with LSIL, 0.49% with HSIL, 0.03% with ICC. The highest median age was observed in ASC-H group with 54 years old. Females with primary school education or lower have the highest positive rates. The overall HPV prevalence was 8.60%. The relatively prevalent HPV types were HPV52, 58, 16, 39, 51. HPV16, HPV18, HPV58, HPV33 and HPV52 were the top5 predominant types in ICC patients. 17.41% females suffered from multiple HPV infection with the most frequently co-infection subtypes being HPV52, HPV58 and HPV16. The prevalence of all HPV subtypes increased with age. Multiple HPV infections accounted for a larger proportion in those aged above 55 years. The peak HPV16 prevalence was observed in ICC group in cases aged 45-49 and 55-59. The peak HPV33 prevalence was observed in younger individuals aged 40-44 who developed ICC. Conclusion: More action should be taken against HPV33 infection.

A stepwise docking molecular dynamics approach for simulating antibody recognition with substantial conformational changes.

Conformational changes or rearrangements are common events during inter-biomolecular recognition. Tracking these changes are essential for exploring the allosteric mechanism and it is usually achieved by molecular dynamics simulation in silico. We previously identified a broad-neutralizing antibody against H5 influenza virus, 13D4, and solved the crystal structures of the free 13D4 Fab and its complex with hemagglutinin (HA). Structural comparison of the unbound and bound 13D4 Fabs showed that the heavy chain complementarity-determining region 3 (HCDR3) undergoes a substantial conformational rearrangement when it recognizes the receptor-binding site (RBS). Here, we used molecular dynamics (MD) to simulate the conformational changes that occur during antibody recognition. We showed that neither conventional MD nor steered MD could recapitulate the loop fitting of the RBS structure contour. Consequently, to simulate these challenging conformational changes, we engaged a stepwise docking MD method that allowed for the gradual docking of the ligand to receptor. This new method recapitulates the bound shape of the HCDR3 and provides the best approximation of the shape rendered by the co-crystal structure, with an RMSD of 0.926 Å. This strategy affords a flexible MD approach for simulating complicated conformational changes that occur during molecular recognition, and helps to provide an understanding of the involved allosteric mechanism.

Identification of Strategic Residues at the Interface of Antigen-Antibody Interactions by In Silico Mutagenesis.

Structural information pertaining to antigen-antibody interactions is fundamental in immunology, and benefits structure-based vaccine design. Modeling of antigen-antibody immune complexes from co-crystal structures or molecular docking simulations provides an extensive profile of the epitope at the interface; however, the key amino acids involved in the interaction must be further clarified, often through the use of experimental mutagenesis and subsequent binding assays. Here, we describe an in silico mutagenesis method to identify key sites at antigen-antibody interfaces, using significant increase in pH-dependency energy among saturated point mutations. Through a comprehensive analysis of the crystal structures of three antigen-antibody immune complexes, we show that a cutoff value of 1 kcal/mol of increased interaction energy provides good congruency with the experimental non-binding mutations conducted in vitro. This in silico mutagenesis strategy, in association with energy calculations, may provide an efficient tool for antibody-antigen interface analyses, epitope optimization, and/or conformation prediction in structure-based vaccine design.

Atomic structures of Coxsackievirus A6 and its complex with a neutralizing antibody.

Coxsackievirus A6 (CVA6) has recently emerged as a major cause of hand, foot and mouth disease in children worldwide but no vaccine is available against CVA6 infections. Here, we demonstrate the isolation of two forms of stable CVA6 particles-procapsid and A-particle-with excellent biochemical stability and natural antigenicity to serve as vaccine candidates. Despite the presence (in A-particle) or absence (in procapsid) of capsid-RNA interactions, the two CVA6 particles have essentially identical atomic capsid structures resembling the uncoating intermediates of other enteroviruses. Our near-atomic resolution structure of CVA6 A-particle complexed with a neutralizing antibody maps an immune-dominant neutralizing epitope to the surface loops of VP1. The structure-guided cell-based inhibition studies further demonstrate that these loops could serve as excellent targets for designing anti-CVA6 vaccines.Coxsackievirus A6 (CVA6) causes hand, foot and mouth disease in children. Here the authors present the CVA6 procapsid and A-particle cryo-EM structures and identify an immune-dominant neutralizing epitope, which can be exploited for vaccine development.

A shared N-terminal hydrophobic tail for the formation of nanoparticulates.

AIM: Nanoparticulate design is important for the production of nanotechnological materials and passive immunogens. Using lessons from our hepatitis E vaccine, we herein design protein-based nanoparticles through incorporation of an N-terminal hydrophobic tail (NHT, located on HEV ORF2 aa368-460). MATERIALS & METHODS: Flu HA1, HIV gp41/gp120/p24, HBsAg and HPV16 L2 were fused with NHT, expressed in Escherichia coli and subjected to self-assembly in vitro. Nanosized particles were characterized by size-exclusion chromatography and negative electron microscopy. Immunogenicity was assessed in mice. RESULTS: All the NHT-fused proteins spontaneously formed nanoparticulates and presented with immunogenicity approximately 2-log over their nonassembling forms. CONCLUSION: Protein self-assembly provides an attractive means to create nanosized particles that bear specific antigens. Our strategy outlines a novel and shared method for the design of immunogenic nanoparticles.

The C-Terminal Arm of the Human Papillomavirus Major Capsid Protein Is Immunogenic and Involved in Virus-Host Interaction.

Cervical cancer is the second most prevalent malignant tumor among women worldwide. High-risk human papillomaviruses (HPVs) are believed to be the major causative pathogens of mucosal epithelial cancers including cervical cancer. The HPV capsid is made up of 360 copies of major (L1) and 72 copies of minor (L2) capsid proteins. To date, limited high-resolution structural information about the HPV capsid has hindered attempts to understand details concerning the mechanisms by which HPV assembles and infects cells. In this study, we have constructed a pseudo-atomic model of the HPV59 L1-only capsid and demonstrate that the C-terminal arm of L1 participates in virus-host interactions. Moreover, when conjugated to a scaffold protein, keyhole limpet hemocyanin (KLH), this arm is immunogenic in vivo. These results provide new insights that will help elucidate HPV biology, and hence pave a way for the design of next-generation HPV vaccines.