Preparation and properties of a papillomavirus infectious intermediate and its utility for neutralization studies

Virology. 2014 Jan 20;449:304-16. doi: 10.1016/j.virol.2013.10.038. Epub 2013 Dec 20.


We show that minor capsid protein L2 is full length in clinical virion isolates and prepare furin-cleaved pseudovirus (fcPsV) as a model of the infectious intermediate for multiple human papillomavirus (HPV) types. These fcPsV do not require furin for in vitro infection, and are fully infectious in vivo. Both the γ-secretase inhibitor XXI and carrageenan block fcPsV infection in vitro and in vivo implying that they act after furin-cleavage of L2. Despite their enhanced exposure of L2 epitopes, vaccination with fcPsV particles fails to induce L2 antibody, although L1-specific responses are similar to PsV with intact L2. FcPsV can be applied in a simple, high-throughput neutralization assay that detects L2-specific neutralizing antibodies with >10-fold enhanced sensitivity compared with the PsV-based assay. The PsV and fcPsV-based assays exhibit similar sensitivity for type-specific antibodies elicited by L1 virus-like particles (VLP), but the latter improves detection of L1-specific cross-type neutralizing antibodies.

Keywords: Carrageenan; Furin; Gamma secretase; Heparin; Human papillomavirus (HPV); Infectious intermediate; L2; Minor capsid protein; Neutralization; Papillomavirus.

MeSH terms

  • Alphapapillomavirus / genetics
  • Alphapapillomavirus / immunology
  • Alphapapillomavirus / physiology*
  • Animals
  • Antibodies, Neutralizing / immunology
  • Antibodies, Viral / immunology
  • Capsid Proteins / administration & dosage
  • Capsid Proteins / genetics
  • Capsid Proteins / immunology*
  • Cross Reactions
  • Furin / metabolism
  • Humans
  • Mice, Inbred BALB C
  • Neutralization Tests
  • Papillomavirus Infections / immunology
  • Papillomavirus Infections / prevention & control
  • Papillomavirus Infections / virology*
  • Papillomavirus Vaccines / administration & dosage
  • Papillomavirus Vaccines / genetics
  • Papillomavirus Vaccines / immunology*


  • Antibodies, Neutralizing
  • Antibodies, Viral
  • Capsid Proteins
  • Papillomavirus Vaccines
  • Furin