title: Mechanisms of human papillomavirus type 16 neutralization by l2 cross-neutralizing and l1 type-specific antibodies.
abstract: Pseudovirions of human papillomavirus type 16 (HPV16), the principal etiologic agent in 50% of cervical cancers, were used as a model system to investigate the cell surface interactions involved in the exposure of the broadly cross-neutralizing papillomavirus L2 epitopes. These neutralizing epitopes were exposed only after cell surface binding and a subsequent change in capsid conformation that permitted cleavage by the cellular protease furin at a specific highly conserved site in L2 that is immediately upstream of the cross-neutralizing epitopes. Unexpectedly, binding of L2 antibodies led to the release of the capsid/antibody complexes from the cell surface and their accumulation on the extracellular matrix. Study of the dynamics of exposure of the L2 epitopes further revealed that representatives of the apparently dominant class of L1-specific neutralizing antibodies induced by virus-like particle vaccination prevent infection, not by preventing cell surface binding but rather by preventing the conformation change involved in exposure of the L2 neutralizing epitope. These findings suggest a dynamic model of virion-cell surface interactions that has implications for both evolution of viral serotypes and the efficacy of current and future HPV vaccines.
authors.affiliation: Laboratory of Cellular Oncology, National Cancer Institute, National Institutes of Health, Bethesda, Maryland 20892, USA. pmd@nih.gov
authors.forename: Patricia M
authors.initials: PM
authors.lastname: Day
authors.forename: Ratish
authors.initials: R
authors.lastname: Gambhira
authors.forename: Richard B S
authors.initials: RB
authors.lastname: Roden
authors.forename: Douglas R
authors.initials: DR
authors.lastname: Lowy
authors.forename: John T
authors.initials: JT
authors.lastname: Schiller
mesh_terms: D000911:Antibodies, Monoclonal; D000914:Antibodies, Viral / Q000276:immunology*; D000956:Antigens, Viral; D036022:Capsid Proteins / Q000737:chemistry / Q000276:immunology; D002460:Cell Line; D002462:Cell Membrane / Q000378:metabolism; D003429:Cross Reactions / Q000276:immunology*; D000939:Epitopes; D005109:Extracellular Matrix; D052162:Human papillomavirus 16 / Q000276:immunology*; D006801:Humans; D009500:Neutralization Tests; D053918:Papillomavirus Vaccines / Q000276:immunology; D011487:Protein Conformation; D014612:Vaccines
chemical_list: D000911:Antibodies, Monoclonal; D000914:Antibodies, Viral; D000956:Antigens, Viral; D036022:Capsid Proteins; D000939:Epitopes; D053918:Papillomavirus Vaccines; D014612:Vaccines