Surface Conformational and Linear Epitopes on HPV-16 and HPV-18 L1 Virus-like Particles as Defined by Monoclonal Antibodies

Abstract

A panel of 24 monoclonal antibodies (MAbs) was generated against human papillomavirus (HPV) types 16 and 18 L1 virus-like particles (VLPs). The MAbs were screened for reactivity to a variety of VLPs prepared from HPV-6, -11, -16, -18, -31, -33, -35, and -45, cottontail rabbit papillomavirus, bovine papillomavirus type 1, and a set of 35 overlapping 20-amino-acid peptides spanning the entire HPV-16 L1 gene. Type-specific linear and conformational surface epitopes were detected as well as several cross-reactive linear epitopes that showed various levels of cross-reactivity between different genital HPV and animal papillomavirus L1s. Most of the linear epitopes were mapped using synthetic peptides, and the epitopes were identified as being either surface or buried within the VLP as defined by the pattern of reactivity in ELISA using intact and disrupted VLP antigen. These MAbs may be useful reagents to help define neutralizing epitopes of HPV-16 and -18 when infectivity assays become available, and to define the regions of L1 that are exposed on the surface or buried within the assembled capsid.

Validation of multiplexed human papillomavirus serology using pseudovirions bound to heparin-coated beads

“…mAbs 6.M48, 11.H3, 16.V5, 18.J4, 31.A6, 52.A7 and 52.C1 were a kind gift from Dr Neil Christensen (Christensen et al, 1996a(Christensen et al, , b, 2001Rizk et al, 2008). Validation panels of serum samples came from five previously published studies.…”

“…These were raised against HPV-6 (6.M48), HPV-11 (11.H3), , , HPV-31 (31.A6) and HPV-52 (52.A7 and 52.C1) (Christensen et al, 1996a(Christensen et al, , b, 2001Rizk et al, 2008). The mAbs were tested at final dilutions of 1 : 500 and 1 : 1500.…”

Characterization of virus-like particles in GARDASIL® by cryo transmission electron microscopy

“…The main benefit of the disassembly/reassembly process was to improve the stability of the VLP preparations since fully closed and discrete VLPs are less prone to aggregation 15,31). This treatment was observed to increase the surface antigenicity for HPV 16 of clinically relevant epitopes such as those of mAb H16.V5 -particularly those known to be neutralizing in pseudovirion neutralization assay [10][11][12] and to be immuno dominant when analyzed by competition assay using human sera of naturally infected individuals. 13 Epitopespecific antigenicity is important to our understanding of the VLP structures, particularly the presence of the neutralizing epitopes and resemblance to authentic virions.…”

“…Mouse mAb IgGs Mouse mAbs, H16.V5 and H11.B2, [10][11][12] were produced in cell culture or ascites using the hybridoma cell lines provided by Professor Neil Christensen at Penn State University (Hershey, PA). Standard Protein A chromatography was used to purify IgGs.…”

The humoral response to Gardasil over four years as defined by Total IgG and competitive Luminex immunoassay

“…The H16.V5 antibody has been show to be HPV 16 type-specific, conformational and neutralizing. 46,47 The H18.R5 antibody has been shown to recognize both HPV 18 and HPV 45 conformational VLPs and neutralize both A7 species members. 46,48 This observation suggests variability between HPV types in utilization of immunodominant epitope on L1 VLPs.…”