Chimeric papillomavirus-like particles expressing a foreign epitope on capsid surface loops

Abstract

Neutralization capsid epitopes are important determinants for antibody-mediated immune protection against papillomavirus (PV) infection and induced disease. Chimeric L1 major capsid proteins of the human PV type 16 (HPV-16) and the bovine PV type 1 (BPV-1) with a foreign peptide incorporated into several capsid surface loops self-assembled into pentamers or virus-like particles (VLP). Binding patterns of neutralizing monoclonal antibodies (MAb) and immunization of mice confirmed (i) that regions around aa 282-286 and 351-355 contribute to neutralization epitopes and identified the latter region as an immunodominant site and (ii) that placing a foreign peptide in the context of an assembled structure markedly enhanced its immunogenicity. Pentamers disassembled from wild-type HPV-16 and BPV-1 VLPs displayed some of the neutralization epitopes that were detected on fully assembled VLPs, but were deficient for binding a subset of neutralizing MAb that inhibit cell attachment.Papillomavirus (PV) infections are widespread in animals and humans, causing mostly benign epithelial proliferations, papillomas or warts, of the skin and mucous membranes (Howley, 1991 ;Lowy et al., 1994 ; zur Hausen, 1991). Infection with oncogenic types, most often human PV type 16 (HPV-16), has been aetiologically associated with the development of anogenital malignancies, in particular cervical cancer (zur Hausen, 1994). PVs are nonenveloped " 8 kb double-stranded DNA viruses with a T l 7 icosahedral symmetry and a

Papillomavirus-Like Particles Are an Effective Platform for Amyloid-β Immunization in Rabbits and Transgenic Mice

“…Several attempts have been made to provide vaccines that are able to overcome B cell tolerance, e.g., by linkage of self-Ags to foreign Th epitopes (14), or by coapplication of strong adjuvants. Recently, antigenic peptides have been fused or cross-linked to the major capsid protein L1 of papillomaviruses (PV), providing self-assembling empty viral capsids or virus-like particles (VLP), that express the foreign peptide on the particle surface in a repetitive and ordered array (15)(16)(17). Immunizations with VLP have induced high-titer and high-avidity (auto)-reactive IgG Ab even without coadministration of adjuvants.…”

“…Sf9 insect cells were infected with baculovirus stocks and lysed, and high-molecular-mass structures were separated by density gradient ultracentrifugation. VLP-containing bands were collected and dialyzed against PBS/0.5M NaCl/0.05% NaN 3 (17,22). BPV1 L1/L2-VLP consisting of wild type (wt) L1 major plus L2 minor capsid proteins were generated in a similar manner (21).…”

“…To generate recombinant baculoviruses expressing the A␤ epitope DAE FRHDSG (corresponding to 1-9 aa of the human A␤ protein) on a predicted surface loop of L1 VLP as a fusion protein, oligonucleotides encoding the epitope were inserted by inverse-touchdown PCR into an immunogenic region (between 133/134 aa) of the BPV1 L1 major capsid protein using pEVmod transfer vector as previously described (17). The forward and reverse primer sequences, respectively, were as follows: 5Ј-GACATGACTCAGGAACCCAAACAACAGATGAC-3Јand 5Ј-GGAA TTCTGCATCGGTGACTTTTCTATTCAC-3Ј.…”

Human papillomavirus type 6 virus-like particles present overlapping yet distinct conformational epitopes

“…We and others have shown that the epitopes recognized by HPV neutralizing monoclonal antibodies (mAbs), which are generally type-specific and conformation-dependent, map to these regions (Christensen et al, 2001;Ludmerer et al, 1996Ludmerer et al, , 1997Ludmerer et al, , 2000McClements et al, 2001;Roden et al, 1997). Furthermore, structural studies of HPV capsomers and VLPs have shown that these divergent sequence regions are surface-exposed (Chen et al, 2000), and other studies have shown that substitution of these regions with non-L1 sequences results in the presentation of foreign epitopes on VLPs (Chackerian et al, 1999;Slupetzky et al, 2001). …”

Human Papillomavirus and Related Diseases - From Bench to Bedside - A Clinical Perspective

“…The two cysteines that participate in the interpentamer disulphide bonding within the virion or in the virion-sized particles are shown in yellow, together with their residue numbers, 175 and 428. (Modis et al, 2002) Some residues in the L1 protein, such as Asp202, Cys175, and Cys428 of HPV16 L1, are very important for VLP formation (Slupetzky et al, 2001), however some residues at the C'-terminus can be truncated and replaced with heterologous epitopes or short polypeptides up to 60 amino acids without disrupting the assembly of VLPs (Paintsil et al, 1996;Müller et al, 1997;Paz De la Rosa et al, 2009). These chimeric VLPs (cVLPs) can induce strong immune responses against not only the inserted epitopes or polypeptides, but also the VLP shell (Freyschmidt et al, 2004;Varsani et al, 2003a;Xu et al, 2006).…”