Protection against heterologous human papillomavirus challenge by a synthetic lipopeptide vaccine containing a broadly cross-neutralizing epitope of L2

Abstract

Persistent infection with the high-risk subset of genitotropic human papillomavirus (HPV) genotypes is a necessary cause of cervical cancer. Given the global burden of cervical cancer, a low-cost, broadly protective vaccine is needed. RG-1 is a crossneutralizing and protective monoclonal antibody that recognizes residues 17-36 of HPV16 minor capsid protein L2. Because this epitope is highly conserved in divergent HPV types, we determined whether vaccination with HPV16 L2 17-36 peptide is broadly protective. The peptide was administered to BALB/c mice three times at monthly intervals, either alone or in the context of a synthetic lipopeptide vaccine candidate (P25-P2C-HPV) produced by linkage of the HPV peptide with a broadly recognized T helper epitope (P25) and the Toll-like receptor-2 (TLR2) ligand dipalmitoyl-S-glyceryl cysteine (P2C). In contrast to vaccination with the L2 17-36 peptide or P25-P2C alone, a potent L2-specific antibody response was generated to the P25-P2C-HPV lipopeptide when delivered either s.c. or intranasally. Sera from mice vaccinated with the P25-P2C-HPV lipopeptide neutralized not only HPV16 pseudovirions but also other evolutionarily divergent oncogenic genital (HPV18, HPV45) and cutaneous (HPV5, BPV1) types. The L2-specific antibody response depended on MHC class II, CD40, and MyD88 signaling. Additionally, vaccination with the P25-P2C-HPV lipopeptide protected mice from homologous challenge with HPV16 pseudovirions at cutaneous and genital sites and heterologous challenge with HPV45 pseudovirions. If provided in the appropriate context, therefore, HPV16 L2 17-36 might be used in a totally synthetic cross-protective HPV vaccine. G enitotropic human papillomavirus (HPV) infections are considered the most common sexually transmitted infection in the United States (1). The major manifestations of anogenital HPV include genital warts (condyloma acuminatum) and anogenital intraepithelial neoplasia. If left untreated, a small fraction of persistent high-risk HPV infections progresses to cancer. The presence of HPV DNA has been reported in 99.7% of cervical carcinomas worldwide, indicating that HPV infection is a necessary cause of this cancer and that this disease can be prevented by prophylactic HPV vaccination (2).Approximately 35 of the Ͼ100 subtypes of HPV are specific for the anogenital epithelium and have varying potentials for malignant transformation (3). Of the 15 oncogenic genital HPV types, HPV16 is the most common, followed by HPV18 and HPV45 (contributing Ϸ50%, 20%, and 10%, respectively, of cervical cancer cases worldwide). Public health efforts have successfully reduced the incidence and mortality of cervical cancer with the implementation of cervical cytology screening programs. Women who do not undergo regular screening account for most of the patients with invasive cancers (4), and cervical cancer remains the second most common cause of cancer death in women worldwide and the most prevalent cancer in women of sub-Saharan Africa, Central America, south-central Asia, and Me...

Exploratory clinical studies of a synthetic HIV-1 Tat epitope vaccine in asymptomatic treatment-naïve and antiretroviral-controlled HIV-1 infected subjects plus healthy uninfected subjects

“…TUTI-16 contains a Toll like receptor 2 (TLR2) agonist designed to enhance the antibody response. [23][24][25]29,30 However this action would also induce cells of the innate immune system to secrete cytokines that activate CD4 + T cells and enhance HIV VL. 23,29,30 Activating cytokines …”

A Modular Approach to Assembly of Totally Synthetic Self-adjuvanting Lipopeptide-based Vaccines Allows Conformational Epitope Building

“…3A) was used to ensure formation of the correct disulfide bond assignments within the ST sequence (23). Trityl (Trt)-protecting groups used at Cys 5 and Cys 10 were removed during the TFA cleavage procedure, and subsequent air oxidation catalyzed by 2,2Ј-dithiodipyridine was then performed for formation of the Cys 5 -Cys 10 disulfide bond. The Cys 6 -Cys 14 disulfide bond was formed by iodine-mediated deprotection and concomitant oxidation of the acetamidomethyl-protected cysteine residues used at these positions.…”

“…The self-adjuvanting properties of lipopeptides abolish the need for additional, potentially toxic adjuvants in vaccine preparations because the lipid moiety Pam2Cys provides the required stimulatory signals to the immune system through engagement of toll-like receptors present on dendritic cells. This form of vaccine candidate is capable not only of inducing humoral and cell-mediated immunity depending on the nature of the target epitope(s) but also mucosal immunity if administered intranasally, a property that potentially removes the requirement for needle vaccine delivery (5)(6)(7)(8)(9).…”

“…Three T H epitopes were used: (i) T MV , which has the sequence KLIPNASLIENCTKAEL and is derived from the fusion protein of the Morbillivirus canine distemper virus (16) and which demonstrates promiscuity between different MHC class II molecules from the same and different species; (ii) T FLU , which is derived from the light chain of influenza virus hemagglutinin, has the sequence ALNNRFQ-IKGVELKS (21),and is an effective T H epitope in BALB/c mice; and (iii) T OVA , which is derived from ovalbumin, has the sequence ISQAVHAAHAEINEAGR (22), and is an effective CD4 ϩ T H epitope in C57BL/6 mice. Peptide Synthesis-Peptides, lipopeptides, and lipopeptide modules were synthesized, purified, and characterized in house using Fmoc chemistry throughout as described elsewhere (5,11,13); the specific protocols used are detailed below.…”

EUROGIN 2008 roadmap on cervical cancer prevention

“…Although natural infection and immunisation with L1/L2 VLPs fails to elicit anti-L2 antibody responses, vaccination with bacterially expressed L2 protein or peptides derived from L2, results in the production of neutralising antibodies that are protective in animal models. [50][51][52] Studies demonstrate that L2 is poorly exposed in native HPV virions, 53 but 1 or more L2 neutralising epitopes [54][55][56] are exposed when the HPV capsid undergoes a conformational change upon binding to its cellular receptors.…”