scholarly journals Simultaneous Quantitation of Antibodies to Neutralizing Epitopes on Virus-Like Particles for Human Papillomavirus Types 6, 11, 16, and 18 by a Multiplexed Luminex Assay

2003 ◽  
Vol 10 (1) ◽  
pp. 108-115 ◽  
Author(s):  
David Opalka ◽  
Charles E. Lachman ◽  
Stefani A. MacMullen ◽  
Kathrin U. Jansen ◽  
Judith F. Smith ◽  
...  

ABSTRACT Several different methods have been developed to quantitate neutralizing antibody responses to human papillomaviruses (HPVs), including in vivo neutralization assays, in vitro pseudoneutralization assays, competitive radioimmunoassays (cRIAs), and enzyme-linked immunosorbent assays. However, each of these techniques possesses one or more limitations that preclude testing large numbers of patient sera for use in natural history studies and large vaccine clinical trials. We describe here a new multiplexed assay, by using the Luminex Laboratory MultiAnalyte Profiling (LabMAP3) assay system, that can simultaneously quantitate neutralizing antibodies to human papillomavirus types 6, 11, 16, and 18 in 50 μl of serum. The HPV-Luminex competitive immunoassay measures titers of polyclonal antibodies in serum capable of displacing phycoerythrin-labeled detection monoclonal antibodies binding to conformationally sensitive, neutralizing epitopes on the respective virus-like particles. This competitive Luminex immunoassay was found to be as sensitive, accurate, and precise as the currently used cRIAs. An effective HPV vaccine will most likely require several distinct genotypes to protect against multiple cancer causing papillomaviruses. The HPV-Luminex immunoassay should prove to be a useful tool in simultaneously quantitating antibody immune responses to multiple HPV genotypes for natural history infection studies and for monitoring the efficacy of prospective vaccines.

2002 ◽  
Vol 76 (13) ◽  
pp. 6480-6486 ◽  
Author(s):  
Alba-Lucia Combita ◽  
Antoine Touzé ◽  
Latifa Bousarghin ◽  
Neil D. Christensen ◽  
Pierre Coursaget

ABSTRACT The neutralizing activities of polyclonal antibodies and monoclonal antibodies (MAbs) obtained by immunization of mice with L1 virus-like particles (VLPs) were investigated by using pseudovirion infectivity assays for human papillomavirus type 16 (HPV-16), HPV-31, HPV-33, HPV-45, HPV-58, and HPV-59 to obtain a better definition of cross-neutralization between high-risk HPVs. In this study, we confirmed and extended previous studies indicating that most genital HPV genotypes represent separate serotypes, and the results suggest that the classification of serotypes is similar to that of genotypes. In addition, three cross-neutralizing MAbs were identified (HPV-16.J4, HPV-16.I23, and HPV-33.E12). MAb HPV-16.J4 recognized a conserved linear epitope located within the FG loop of the L1 protein, and HPV-16.I23 recognized another located within the DE loop. The results suggested that reactivity of MAb HPV-16.I23 to L1 protein is lost when leucine 152 of the HPV-16 L1 protein is replaced by phenylalanine. This confirmed the existence of linear epitopes within the L1 protein that induce neutralizing antibodies, and this is the first evidence that such linear epitopes induce cross-neutralization. However, the cross-neutralization induced by L1 VLPs represents less than 1% of the neutralizing activity induced by the dominant conformational epitopes, and it is questionable whether this is sufficient to offer cross-protection in vivo.


2004 ◽  
Vol 78 (23) ◽  
pp. 12901-12909 ◽  
Author(s):  
David Baud ◽  
Françoise Ponci ◽  
Martine Bobst ◽  
Pierre De Grandi ◽  
Denise Nardelli-Haefliger

ABSTRACT Cervical cancer results from cervical infection by human papillomaviruses (HPVs), especially HPV16. An effective vaccine against these HPVs is expected to have a dramatic impact on the incidence of this cancer and its precursor lesions. The leading candidate, a subunit prophylactic HPV virus-like particle (VLP) vaccine, can protect women from HPV infection. An alternative improved vaccine that avoids parenteral injection, that is efficient with a single dose, and that induces mucosal immunity might greatly facilitate vaccine implementation in different settings. In this study, we have constructed a new generation of recombinant Salmonella organisms that assemble HPV16 VLPs and induce high titers of neutralizing antibodies in mice after a single nasal or oral immunization with live bacteria. This was achieved through the expression of a HPV16 L1 capsid gene whose codon usage was optimized to fit with the most frequently used codons in Salmonella. Interestingly, the high immunogenicity of the new recombinant bacteria did not correlate with an increased expression of L1 VLPs but with a greater stability of the L1-expressing plasmid in vitro and in vivo in absence of antibiotic selection. Anti-HPV16 humoral and neutralizing responses were also observed with different Salmonella enterica serovar Typhimurium strains whose attenuating deletions have already been shown to be safe after oral vaccination of humans. Thus, our findings are a promising improvement toward a vaccine strain that could be tested in human volunteers.


1999 ◽  
Vol 73 (11) ◽  
pp. 9609-9613 ◽  
Author(s):  
Denise Nardelli-Haefliger ◽  
Richard Roden ◽  
Carole Balmelli ◽  
Alexandra Potts ◽  
John Schiller ◽  
...  

ABSTRACT We have recently shown that nasal immunization of anesthetized mice with human papillomavirus type 16 (HPV16) virus-like particles (VLPs) is highly effective at inducing both neutralizing immunoglobulin A (IgA) and IgG in genital secretions, while parenteral immunization induced only neutralizing IgG. Our data also demonstrated that both isotypes are similarly neutralizing according to an in vitro pseudotyped neutralization assay. However, it is known that various amounts of IgA and IgG are produced in genital secretions along the estrous cycle. Therefore, we have investigated how this variation influences the amount of HPV16 neutralizing antibodies induced after immunization with VLPs. We have compared parenteral and nasal protocols of vaccination with daily samplings of genital secretions of mice. Enzyme-linked immunosorbent assay analysis showed that total IgA and IgG inversely varied along the estrous cycle, with the largest amounts of IgA in proestrus-estrus and the largest amount of IgG in diestrus. This resulted in HPV16 neutralizing titers of IgG only being achieved during diestrus upon parenteral immunization. In contrast, nasal vaccination induced neutralizing titers of IgA plus IgG throughout the estrous cycle, as confirmed by in vitro pseudotyped neutralization assays. Our data suggest that mucosal immunization might be more efficient than parenteral immunization at inducing continuous protection of the female genital tract.


2012 ◽  
Vol 19 (7) ◽  
pp. 1075-1082 ◽  
Author(s):  
Patricia M. Day ◽  
Yuk-Ying S. Pang ◽  
Rhonda C. Kines ◽  
Cynthia D. Thompson ◽  
Douglas R. Lowy ◽  
...  

ABSTRACTPapillomavirus L2-based vaccines have generally induced low-level or undetectable neutralizing antibodies in standardin vitroassays yet typically protect well againstin vivoexperimental challenge in animal models. Herein we document that mice vaccinated with an L2 vaccine comprising a fusion protein of the L2 amino acids 11 to 88 of human papillomavirus type 16 (HPV16), HPV18, HPV1, HPV5, and HPV6 were uniformly protected from cervicovaginal challenge with HPV16 pseudovirus, but neutralizing antibodies against HPV16, -31, -33, -45, or -58 were rarely detected in their sera using a standardin vitroneutralization assay. To address this discrepancy, we developed a neutralization assay based on anin vitroinfectivity mechanism that more closely mimics thein vivoinfectious process, specifically by spaciotemporally separating primary and secondary receptor engagement and correspondingly by altering the timing of exposure of the dominant L2 cross-neutralizing epitopes to the antibodies. With the new assay, titers in the 100 to 10,000 range were measured for most sera, whereas undetectable neutralizing activities were observed with the standard assay.In vitroneutralizing titers measured in the serum of mice after passive transfer of rabbit L2 immune serum correlated with protection from cervicovaginal challenge of the mice. This “L2-based”in vitroneutralization assay should prove useful in critically evaluating the immunogenicity of L2 vaccine candidates in preclinical studies and future clinical trials.


2006 ◽  
Vol 80 (10) ◽  
pp. 4664-4672 ◽  
Author(s):  
Joseph J. Carter ◽  
Greg C. Wipf ◽  
Margaret M. Madeleine ◽  
Stephen M. Schwartz ◽  
Laura A. Koutsky ◽  
...  

ABSTRACT The variable surface loops on human papillomavirus (HPV) virions required for type-specific neutralization by human sera remain poorly defined. To determine which loops are required for neutralization, a series of hybrid virus-like particles (VLPs) were used to adsorb neutralizing activity from HPV type 16 (HPV16)-reactive human sera before being tested in an HPV16 pseudovirion neutralization assay. The hybrid VLPs used were composed of L1 sequences of either HPV16 or HPV31, on which one or two regions were replaced with homologous sequences from the other type. The regions chosen for substitution were the five known loops that form surface epitopes recognized by monoclonal antibodies and two additional variable regions between residues 400 and 450. Pretreatment of human sera, previously found to react to HPV16 VLPs in enzyme-linked immunosorbent assays, with wild-type HPV16 VLPs and hybrid VLPs that retained the neutralizing epitopes reduced or eliminated the ability of sera to inhibit pseudovirus infection in vitro. Surprisingly, substitution of a single loop often ablated the ability of VLPs to adsorb neutralizing antibodies from human sera. However, for all sera tested, multiple surface loops were found to be important for neutralizing activity. Three regions, defined by loops DE, FG, and HI, were most frequently identified as being essential for binding by neutralizing antibodies. These observations are consistent with the existence of multiple neutralizing epitopes on the HPV virion surface.


2021 ◽  
Author(s):  
Apurva T. Prabhakar ◽  
Claire D. James ◽  
Dipon Das ◽  
Raymonde Otoa ◽  
Matthew Day ◽  
...  

AbstractDuring the human papillomavirus 16 (HPV16) life cycle, the E2 protein interacts with host factors to regulate viral transcription, replication and genome segregation/retention. Our understanding of host partner proteins and their roles in E2 functions remains incomplete. Here, we demonstrate that CK2 phosphorylation of E2 on serine 23 promotes interaction with TopBP1 in vitro and in vivo, and that E2 is phosphorylated on this residue during the HPV16 life cycle. We investigated the consequences of mutating serine 23 on E2 functions. E2-S23A activates and represses transcription identically to E2-WT (wild-type), and E2-S23A is as efficient as E2-WT in transient replication assays. However, E2-S23A has compromised interaction with mitotic chromatin when compared with E2-WT. In E2-WT cells, both E2 and TopBP1 levels increase during mitosis when compared with vector control cells. In E2-S23A cells, neither E2 nor TopBP1 levels increase during mitosis. We next tested whether this difference in E2-S23A levels during mitosis disrupts E2 plasmid retention function. We developed a novel plasmid retention assay and demonstrate that E2-S23A is deficient in plasmid retention when compared with E2-WT. siRNA targeted knockdown of TopBP1 abrogates E2-WT plasmid retention function. Introduction of the S23A mutation into the HPV16 genome resulted in delayed immortalization of human foreskin keratinocytes (HFK) and higher episomal viral genome copy number in resulting established HFK. Overall, our results demonstrate that CK2 phosphorylation of E2 on serine 23 promotes interaction with TopBP1, which is critical for E2 plasmid retention function and in HPV16 immortalization of keratinocytes.ImportanceHuman papillomaviruses are causative agents in around 5% of all cancers, with no specific anti-viral therapeutics available for treating infections or resultant cancers. In this report, we demonstrate that phosphorylation of HPV16 E2 by CK2 promotes formation of a complex formation with the cellular protein TopBP1 in vitro and in vivo. This complex results in stabilization of E2 during mitosis and mediates plasmid retention by E2. This function promotes the partitioning of viral genomes into the nuclei of daughter cells following mitosis. We demonstrate that CK2 phosphorylates E2 on serine 23 in vivo, and that CK2 inhibitors disrupt the E2-TopBP1 complex. Mutation of E2 serine 23 to alanine disrupts the HPV16 life cycle, demonstrating a critical function for this residue. Together, our results suggest that CK2 inhibitors may disrupt the E2-TopBP1 dependent HPV16 life cycle and potentially kill HPV16 positive cancers, which lays a molecular foundation to develop novel therapeutic approaches for combating HPV16 disease.


Viruses ◽  
2019 ◽  
Vol 11 (6) ◽  
pp. 507 ◽  
Author(s):  
Christopher A. Gonelli ◽  
Georges Khoury ◽  
Rob J. Center ◽  
Damian F.J. Purcell

A prophylactic vaccine eliciting both broad neutralizing antibodies (bNAbs) to the HIV-1 envelope glycoprotein (Env) and strong T cell responses would be optimal for preventing HIV-1 transmissions. Replication incompetent HIV-1 virus-like particles (VLPs) offer the opportunity to present authentic-structured, virion-associated Env to elicit bNAbs, and also stimulate T cell responses. Here, we optimize our DNA vaccine plasmids as VLP expression vectors for efficient Env incorporation and budding. The original vector that was used in human trials inefficiently produced VLPs, but maximized safety by inactivating RNA genome packaging, enzyme functions that are required for integration into the host genome, and deleting accessory proteins Vif, Vpr, and Nef. These original DNA vaccine vectors generated VLPs with incomplete protease-mediated cleavage of Gag and were irregularly sized. Mutations to restore function within the defective genes revealed that several of the reverse transcriptase (RT) deletions mediated this immature phenotype. Here, we made efficient budding, protease-processed, and mature-form VLPs that resembled infectious virions by introducing alternative mutations that completely removed the RT domain, but preserved most other safety mutations. These VLPs, either expressed from DNA vectors in vivo or purified after expression in vitro, are potentially useful immunogens that can be used to elicit antibody responses that target Env on fully infectious HIV-1 virions.


mBio ◽  
2021 ◽  
Author(s):  
Apurva T. Prabhakar ◽  
Claire D. James ◽  
Dipon Das ◽  
Raymonde Otoa ◽  
Matthew Day ◽  
...  

Human papillomaviruses are causative agents in around 5% of all cancers, with no specific antiviral therapeutics available for treating infections or resultant cancers. In this report, we demonstrate that phosphorylation of HPV16 E2 by CK2 promotes formation of a complex with the cellular protein TopBP1 in vitro and in vivo .


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Brittany Jasperse ◽  
Caitlin M. O’Connell ◽  
Yuxiang Wang ◽  
Paulo H. Verardi

AbstractZika virus (ZIKV), a flavivirus transmitted primarily by infected mosquitos, can cause neurological symptoms such as Guillian–Barré syndrome and microcephaly. We developed several vaccinia virus (VACV) vaccine candidates for ZIKV based on replication-inducible VACVs (vINDs) expressing ZIKV pre-membrane (prM) and envelope (E) proteins (vIND-ZIKVs). These vIND-ZIKVs contain elements of the tetracycline operon and replicate only in the presence of tetracyclines. The pool of vaccine candidates was narrowed to one vIND-ZIKV containing a novel mutation in the signal peptide of prM that led to higher expression and secretion of E and production of virus-like particles, which was then tested for safety, immunogenicity, and efficacy in mice. vIND-ZIKV grows to high titers in vitro in the presence of doxycycline (DOX) but is replication-defective in vivo in the absence of DOX, causing no weight loss in mice. C57BL/6 mice vaccinated once with vIND-ZIKV in the absence of DOX (as a replication-defective virus) developed robust levels of E-peptide-specific IFN-γ-secreting splenocytes and anti-E IgG titers, with modest levels of serum-neutralizing antibodies. Vaccinated mice treated with anti-IFNAR1 antibody were completely protected from ZIKV viremia post-challenge after a single dose of vIND-ZIKV. Furthermore, mice with prior immunity to VACV developed moderate anti-E IgG titers that increased after booster vaccination, and were protected from viremia only after two vaccinations with vIND-ZIKV.


2004 ◽  
Vol 78 (2) ◽  
pp. 821-833 ◽  
Author(s):  
Qian Wang ◽  
Heather Griffin ◽  
Shirley Southern ◽  
Deborah Jackson ◽  
Ana Martin ◽  
...  

ABSTRACT High-risk human papillomaviruses, such as human papillomavirus type 16 (HPV16), are the primary cause of cervical cancer. The HPV16 E1∧E4 protein associates with keratin intermediate filaments and causes network collapse when expressed in epithelial cells in vitro. Here, we show that keratin association and network reorganization also occur in vivo in low-grade cervical neoplasia caused by HPV16. The 16E1∧E4 protein binds to keratins directly and interacts strongly with keratin 18, a member of the type I intermediate-filament family. By contrast, 16E1∧E4 bound only weakly to keratin 8, a type II intermediate-filament protein, and showed no detectable affinity for the type III protein, vimentin. The N-terminal 16 amino acids of the 16E1∧E4 protein, which contains the YPLLXLL motif that is conserved among supergroup A viruses, were sufficient to target green fluorescent protein to the keratin network. When expressed in the SiHa cervical epithelial cell line, the full-length 16E1∧E4 protein caused an almost total inhibition of keratin dynamics, despite the phosphorylation of keratin 18 at serine 33, which normally leads to 14-3-3-mediated keratin solubilization. Mutant 16E1∧E4 proteins which lack the LLKLL motif, or which have lost amino acids from their C termini, and which were compromised in the ability to associate with keratins did not disturb normal keratin dynamics. 16E1∧E4 was found to exist as dimers and hexamers, whereas a C-terminal deletion mutant (16E1∧E4Δ87-92) existed as monomers and formed multimeric structures only poorly. Considered together, our results suggest that by associating with keratins through its N terminus, and by associating with itself through its C terminus, 16E1∧E4 may act as a keratin cross-linker and prevent the movement of keratins between the soluble and insoluble compartments. The increase in avidity associated with multimeric binding may contribute to the ability of 16E1∧E4 to sequester its cellular targets in the cytoplasm.


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