Cervical mucus antibodies against human papillomavirus type 16, 18, and 33 capsids in relation to presence of viral DNA

Assessing the reduction of viral infectivity in HPV16/18-positive women after one, two, and three doses of Gardasil-9 (RIFT): Study protocol

Human Papillomavirus (HPV) prophylactic vaccination has proven effective in preventing new infections, but it does not treat existing HPV infections or associated diseases. Hence, there is still an important reservoir of HPV in adults, as vaccination programs are mainly focused on young women. The primary objective of this non-randomized, open-label trial is to evaluate if a 3-dose regimen of Gardasil-9 in HPV16/18-positive women could reduce the infective capacity of their body fluids. We aim to assess if vaccine-induced antibodies could neutralize virions present in the mucosa, thus preventing the release of infective particles and HPV transmission to sexual partners. As our main endpoint, the E1^E4-HaCaT model will be used to assess the infectivity rate of cervical, anal and oral samples, obtained from women before and after vaccination. HPV DNA positivity, virion production, seroconversion, and the presence of antibodies in the exudates, will be evaluated to attribute infectivity reduction to vaccination. Our study will recruit two different cohorts (RIFT-HPV1 and RIFT-HPV2) of non-vaccinated adult women. RIFT-HPV1 will include subjects with an HPV16/18 positive cervical test and no apparent cervical lesions or cervical lesions eligible for conservative treatment. RIFT-HPV2 will include subjects with an HPV16/18 positive anal test and no apparent anal lesions or anal lesions eligible for conservative treatment, as well as women with an HPV16/18 positive cervical test and HPV-associated vulvar lesions. Subjects complying with inclusion criteria for both cohorts will be recruited to the main cohort, RIFT-HPV1. Three doses of Gardasil-9 will be administered intramuscularly at visit 1 (0 months), visit 2 (2 months) and visit 3 (6 months). Even though prophylactic HPV vaccines would not eliminate a pre-existing infection, our results will determine if HPV vaccination could be considered as a new complementary strategy to prevent HPV-associated diseases by reducing viral spread. Trial registration: https://clinicaltrials.gov/ct2/show/NCT05334706.

Prevalence of antibodies against a cyclic peptide mimicking the FG loop of the human papillomavirus type 16 capsid among Tunisian women

Background

In the past decade, cervical cancer has gone from being the second to the fourth most common cancer in women worldwide, but remains the second most common in developing countries. This cancer is most commonly caused by high-risk types of human papillomavirus (HPV), mainly type 16 (HPV16), which are sexually transmitted. This study aimed to investigate the usefulness of a cyclic synthetic peptide designed from the major L1 capsid protein of HPV16 for detecting anti-HPV16 antibodies.

Methods

We designed and synthetized a peptide that corresponds to the full sequence of the surface-exposed FG loop. We tested the antigenicity of the linear and the cyclic peptides against HPV16 L1 monoclonal antibodies. We used ELISA to detect anti-peptide antibodies in sera and cervical secretions of 179 Tunisian women, and we applied polymerase chain reaction and direct sequencing methods to detect and genotype HPV DNA.

Results

Both the linear and the cyclic peptides were recognized by the same neutralizing monoclonal antibodies, but the cyclic peptide was more reactive with human sera. The prevalence of the anti-peptide antibodies in sera was higher in women with low-grade squamous intraepithelial lesions (LGSIL) than in women with high-grade squamous intraepithelial lesions (HGSIL) (44% and 15%, respectively). This contrasts with HPV16 DNA prevalence. Compared to women from the general population, systemic IgG prevalence was significantly higher among sex workers (25%; P = 0.002) and women with LGSIL (44%; P = 0.001). In addition, systemic IgA and cervical IgG prevalence was higher among sex workers only (P = 0.002 and P = 0.001, respectively). We did not observe anti-peptide IgG antibodies in women with a current HPV16 infection.

Conclusion

Anti-peptide IgG in sera or in cervical secretions could be markers of an effective natural immunization against HPV16. This may open novel perspectives for monitoring vaccinated women and for the design of synthetic peptide-based vaccines.

Serum and cervicovaginal IgG immune responses against α7 and α9 HPV in non-vaccinated women at risk for cervical cancer: Implication for catch-up prophylactic HPV vaccination

BACKGROUND

Cervical cancer associated with high risk-human papillomavirus (HR-HPV) infection is becoming the one of the most common female cancer in many sub-Saharan African countries. First-generation immigrant African women living in Europe are at-risk for cervical cancer, in a context of social vulnerability, with frequent lack of cervical cancer screening and HPV vaccination.

OBJECTIVE

Our objective was to address immunologically the issue of catch-up prophylactic HPV vaccination in first-generation African immigrant women living in France.

METHODS

IgG immune responses and cross-reactivities to α7 (HPV-18, -45 and -68) and α9 (HPV-16, -31, -33, -35, -52 and -58) HPV types, including 7 HR-HPV targeted by the Gardasil-9® prophylactic vaccine, were evaluated in paired serum and cervicovaginal secretions (CVS) by HPV L1-virus-like particles-based ELISA. Genital HPV were detected by multiplex real time PCR (Seegene, Seoul, South Korea).

RESULTS

Fifty-one immigrant women (mean age, 41.7 years; 72.5% HIV-infected) were prospectively included. More than two-third (68.6%) of them carried genital HPV (group I) while 31.4% were negative (group II). The majority (90.2%) exhibited serum IgG to at least one α7/α9 HR-HPV. Serum HPV-specific IgG were more frequently detected in group I than group II (100% versus 68.7%; P = 0.002). The distribution of serum and genital HPV-specific IgG was similar, but mean number of IgG reactivities to α7/α9 HR-HPV was higher in serum than CVS (5.6 IgG per woman in serum versus 3.2 in CVS; P<0.001). Rates of IgG cross-reactivities against HPV different from detected cervicovaginal HPV were higher in serum and CVS in group I than group II. Finally, the majority of groups I and II women (68.6% and 68.7%, respectively) exhibited serum or cervicovaginal IgG to Gardasil-9® HR-HPV, with higher mean rates in group I than group II (6.1 Gardasil-9® HR-HPV per woman versus 1.4; P<0.01). One-third (31.2%) of group II women did not show any serum and genital HPV-specific IgG.

CONCLUSIONS

Around two-third of first-generation African immigrant women living in France showed frequent ongoing genital HPV infection and high rates of circulating and genital IgG to α7/α9 HPV, generally cross-reacting, avoiding the possibility of catch-up vaccination. Nevertheless, about one-third of women had no evidence of previous HPV infection, or showed only low levels of genital and circulating HR-HPV-specific IgG and could therefore be eligible for catch-up vaccination.

Natural and vaccine-induced B cell-derived systemic and mucosal humoral immunity to human papillomavirus

Introduction: Human papillomavirus (HPV) are the causative agent of mucosal neoplasia. Both cervical, anal and oropharyngeal cancers incidence is constantly increasing, making the HPV infection, a significant worldwide concern. Together, the CD8+ T cytotoxic cell-mediated response and the HPV-specific antibody response control most of the HPV infections before the development of cancers.Areas covered: We searched the MEDLINE and EMBASE databases and identified 228 eligible studies from 1987 to 2019 which examines both naturally acquired and vaccine induced humoral immunity against HPV infection in female and male subjects from worldwide origin. Herein, we synthesize current knowledge on the features of systemic and mucosal humoral immunity against HPV. We discuss the issues of the balance between the viral clearance or the escape to the host immune response, the differences between natural and vaccine-induced HPV-specific antibodies and their neutralizing capability. We also discuss the protection afforded after natural infection or following prophylactic vaccination.Expert opinion: Understanding the antibody response induced by HPV infection has led to the design of first-generation prophylactic vaccines. Now, prophylactic vaccination induces protective and long-lasting antibody response which would also strengthened the natural moderate humoral response in people previously exposed to the virus.

Infection and vaccine-induced HPV-specific antibodies in cervicovaginal secretions. A review of the literature

Background

Human papillomavirus (HPV) infects and propagates in the cervical mucosal epithelium. Hence, in addition to assessing systemic immunity, the accurate measurement of cervical immunity is important to evaluate local immune responses to HPV infection and vaccination. This review discusses studies that investigated the presence of infection and vaccine-induced HPV-specific antibodies in cervicovaginal secretions (CVS).

Methods

We searched the two main health sciences databases, PubMed and the ISI Web of Science, from the earliest dates available to March 2019. From the eligible publications, information was extracted regarding: (i) study design, (ii) the reported HPV-specific antibody concentrations in CVS (and the associated serum levels, when provided), (iii) the CVS collection method, and (iv) the immunoassays used.

Results

The systematic search and selection process yielded 44 articles. The evidence of HPV-specific antibodies in CVS after natural infection (26/44) and HPV vaccination (18/44) is discussed. Many studies indicate that HPV-specific antibody detection in CVS is variable but feasible with a variety of collection methods and immunoassays. Most CVS samples were collected by cervicovaginal washing or wicks, and antibody presence was mostly determined by VLP-based ELISAs. The moderate to strong correlation between vaccine-induced antibody levels in serum and in CVS indicates that HPV vaccines generate antibodies that transudate through the cervical mucosal epithelium.

Conclusion

Although HPV-specific antibodies have lower titres in CVS than in serum samples, studies have shown that their detection in CVS is feasible. Nevertheless, the high variability of published observations and the lack of a strictly uniform, well-validated method for the collection, isolation and quantification of antibodies indicates a need for specific methods to improve and standardize the detection of HPV-specific antibodies in CVS.

Asymptomatic oral human papillomavirus (HPV) infection in women with a histopathologic diagnosis of genital HPV

The oral route of human papillomavirus (HPV) transmission is not fully understood. It has been suggested that genital infection can act as a reservoir for oral HPV infection. We investigated the presence of oral HPV DNA and anti-HPV IgA in the buccal cavity of patients with a histopathologic diagnosis of cervical HPV infection. One hundred women underwent oral clinical examinations to detect HPV-DNA by polymerase chain reaction and salivary anti-HPV IgA by indirect immunofluorescence. Information on the personal habits of all the women was collected in personal interviews. Our results showed that 99% of the patients had no clinical manifestations of oral HPV. However, HPV DNA was detected in 81% of oral mucosa samples, and anti-HPV IgA was detected in the saliva of 44% of the patients. Consumption of alcoholic beverages was significantly associated with detection of oral HPV DNA and salivary anti-HPV IgA. Other behavioral risk factors associated with oral HPV and anti-HPV IgA are also discussed. In conclusion, patients with genital HPV infection are at risk for subclinical oral HPV infection. Thus, a molecular assay might be necessary to diagnose such infections.

Use of cervicovaginal fluid for the identification of biomarkers for pathologies of the female genital tract

Cervicovaginal fluid has an important function in the homeostasis and immunity of the lower female genital tract. Analysis of the cervicovaginal fluid proteome may therefore yield important information about the pathogenesis of numerous gynecological pathologies. Additionally, cervicovaginal fluid has great potential as a source of biomarkers for these conditions.

This review provides a detailed discussion about the human cervicovaginal proteome and the proteomics studies performed to characterize this biological fluid. Furthermore, infection-correlated pathological conditions of the female genital tract are discussed for which cervicovaginal fluid has been used in order to identify potential biomarkers. Recent years, numerous studies have analyzed cervicovaginal fluid samples utilizing antibody-based technologies, such as ELISA or Western blotting, to identify biomarkers for preterm birth, premature preterm rupture of membranes, bacterial vaginosis and cervical cancer. The present article will discuss the importance of proteomic technologies as alternative techniques to gain additional meaningful information about these conditions. In addition, the review focuses on recent proteomic studies on cervicovaginal fluid samples for the identification of potential biomarkers. We conclude that the use of proteomic technology for analysis of human cervicovaginal fluid samples is promising and may lead to the discovery of new biomarkers which can improve disease prevention and therapy development.

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

This study developed and validated a high-throughput human papillomavirus (HPV) serology method based on Luminex technology, using pseudovirions (PsVs) of eight mucosal HPV types (HPV-6, -11, -16, -18, -31, -45, -52 and -58) and two cutaneous HPV types (HPV-5 and -38) bound to heparin-coated beads. Analysis with neutralizing type-specific monoclonal antibodies against the included HPV types indicated the type specificity of the assay. Analysis of negative-control serum samples from 63 children and 71 middle-aged women with up to one lifetime sexual partner indicated high specificity. Positive-control serum samples from subjects with known HPV DNA status or clinical diagnosis found expected sensitivities for most of the HPV types in 219 European serum samples, but lower than expected in 124 samples from Africa. HPV-45 and -52 did not react as expected with the human serum samples. The PsV-Luminex method was used to determine the HPV-seropositivity-associated relative risk for future cervical cancer using 208 serum samples from a prospective study of 18 814 women followed for 23 years, analysed previously with standard HPV-16 ELISA. The PsV-Luminex method gave similar results to ELISA (kappa=0.77). As expected, HPV seropositivities assayed using the PsV-Luminex method found an increased risk of cervical cancer for HPV-16 [odds ratio (OR)=7.7, 95 % confidence interval (CI)=2.6-23] and HPV-31 (OR=4.1, 95 % CI=1.6-10.8), non-significant tendencies for increased risk for other mucosal HPV types and no risk for the cutaneous HPV types. In summary, multiplexed HPV serology using mammalian-derived PsVs selected for native conformation by binding to heparin-coated beads was validated as a high-throughput HPV serological method for most of the analysed HPV types.

Binding of human papillomavirus type 16 to heparan sulfate is inhibited by mucosal antibodies from patients with low-grade squamous intraepithelial lesions but not from cervical cancer patients

Mucosal antibodies against human papillomavirus type 16 (HPV16) capsids have been detected in infected women. To determine whether these antibodies recognize and block the receptor site mediating attachment of HPV16 to heparan sulfate, mucus samples from 126 HPV16-associated low-grade squamous intraepithelial lesion (LSIL) and 85 cervical cancer patients, previously found to react to HPV16 virus-like particles (VLP), and 101 normal controls were tested in an inhibition assay, using HPV16 VLP and heparan sulfate proteoglycan-coated plates. Inhibition levels of 9.3-67.2% were mediated by type-specific antibodies in 94.4% of LSIL patients. Cervical cancer cases showed significantly lower levels of inhibition than LSIL samples (P < 0.0001). The potential of antibodies to inhibit infection was explored in a pseudoinfection system using HPV16 pseudovirions. Inhibition of pseudoinfection by LSIL samples was significantly higher than that observed in the controls (P < 0.001) and cervical cancer cases (P < 0.005). These results indicate that mucosal antibodies inhibiting binding of VLP to heparan sulfate are developed in most LSIL patients, but are hardly present in cervical cancer patients.

Reactivity pattern of 92 monoclonal antibodies with 15 human papillomavirus types

Most anti-human papillomavirus (HPV) capsid antibody assays are based on virus-like particles (VLP). We evaluated glutathione S-transferase (GST)-L1 fusion proteins as ELISA antigens for determining type specificity and cross-reactivity of 92 VLP-specific monoclonal antibodies (mAb) generated against nine mucosal alpha papillomavirus types of species 7, 9 and 10. The antibody panel included 25 new mAb, and 24 previously published mAb are further characterized. We determined the cross-reactivity patterns with 15 different HPV types representing 6 species (alpha1, 2, 4, 7, 9 and 10) and neutralization and cross-neutralization properties with HPV types 6, 11, 16, 18 and 45. Eighty-nine (97 %) of the antibodies including 34, 71 and 14 recognizing neutralizing, conformational and linear epitopes, respectively, reacted with the GST-L1 protein of the HPV type used as immunogen, with log titres ranging from 2.0 to 7.3. Of these 89 antibodies, 52 % were monotypic, 20 % showed intra-species and 28 % inter-species cross-reactivity. Log neutralization titres to the immunogen HPV ranged from 1.7 to 5.6. A single cross-neutralizing mAb (H6.L12) was found. ELISA titres were always higher than neutralization titres. All neutralizing epitopes were conformational and mostly type-specific. Our data show that bacterially expressed, affinity-purified GST-L1 fusion proteins display a broad variety of epitopes and thus are well suited for detection of HPV antibodies. Cross-reactivity is associated with linear as well as conformational epitopes. Distantly related mucosal and skin alpha papillomaviruses share some conformational epitopes and the phylogenetic L1-based species definition may not define a serological unit since no species-specific epitope was found.

Cervicovaginal, oral, and serum IgG and IgA responses to human papillomavirus type 16 in women with cervical intraepithelial neoplasia

Oncogenic human papillomaviruses (HPVs) are obligate mucosal pathogens and typically cause localized infections. The mucosal surface of the genital tract also provides the first line of defense against genital HPV infection. Although local antibody production following HPV-infection has been demonstrated, their role in protection from cervical disease is unclear. This study evaluated oral and cervical HPV infection and the associated linkage between HPV-16 oral, cervical and serum antibody responses in 103 women with varying grades of cervical intraepithelial neoplasia (CIN). We found that HPV-16 was the most prevalent cervical HPV infection (30/103, 29.1%) but was only detected in 1.1% (1/91) of the oral samples. Both the frequency and magnitude of HPV-16-specific cervical IgA was significantly elevated in women with CIN 2/3 compared with women with CIN 1 (P = 0.0073 frequency; P = 0.0045 magnitude). Women with cervical HPV-16 infection had significantly higher magnitude and frequency of cervical HPV-16 IgA responses than women without cervical HPV-16 DNA (P = 0.0002 frequency; P = 0.0052 magnitude). Despite our contention that mucosal HPV-16 antibody responses within distinct mucosal compartments may be linked, the concordance analysis carried out within and between mucosal compartments and serum suggests that no such linkage exists and that these compartments may be functioning independently of one another. An HPV-16 specific antibody response in one mucosal compartment in women with CIN is therefore not predictive of a response at another.

Correlates of cervical mucosal antibodies to human papillomavirus 16: Results from a case control study

BACKGROUND

While the cervical mucosal immune response to human papillomavirus (HPV) infection is believed to be central to viral clearance, it is not well characterized. We performed this analysis to determine correlates of HPV-16-specific mucosal antibody response in women at high risk for infection with HPV.

METHODS

Cervical mucosal and serum samples were obtained from participants in a case control study that measured demographic risk factors of cervical disease and HPV infection. An HPV-16 L1-virus-like particle ELISA was used to detect HPV-16-specific IgA and IgG. Antibody level results were correlated with demographic characteristics, sexual history, cervical disease, and HPV detection.

RESULTS

Cervical anti-HPV-16 IgA and IgG inversely correlated with HPV DNA, HPV-16 DNA, and cervical disease.

CONCLUSIONS

These findings suggest that mucosal antibodies may protect against HPV infection and cervical disease. However, additional longitudinal studies evaluating serum and mucosal antibody correlates of incident, persistent, and clearing HPV infection are needed. In addition, standardization of mucosal sample collection and testing methods are required.

Strategies for the prevention of cervical cancer by human papillomavirus vaccination

As cervical cancer is causally associated with 14 high-risk types of human papillomavirus (HPV), a successful HPV vaccine will have a major impact on this disease. Although some persistent HPV infections progress to cervical cancer, host immunity is generally able to clear most HPV infections. Both cell-mediated and antibody responses have been implicated in influencing the susceptibility, persistence or clearance of genital HPV infection. There have been two clinical trials that show that vaccines based on virus-like particles (VLPs) made from the major capsid protein, L1, are able to type specifically protect against cervical intra-epithelial neoplasia and infection. However, there is no evidence that even a mixed VLP vaccine will protect against types not included in the vaccine, and a major challenge that remains is how to engineer protection across a broader spectrum of viruses. Strategies for production of HPV vaccines using different vaccine vectors and different production systems are also reviewed.

Immune responses to human papillomavirus in genital tract of women with cervical cancer

OBJECTIVES

To address a question whether immune responses to HPV infection play a role in control of cervical cancer, we analyzed systemic and mucosal immune responses to HPV in women who underwent radical hysterectomy for cervical cancer (HCC) or loop conization due to cervical dysplasia (LOOP), or had hysterectomy for other reasons (HNN).

METHODS

HPV-specific antibodies in sera and vaginal washes were determined by ELISA using recombinant HPV 16 E7 oncoprotein. Cytokines in vaginal washes were assayed by Linco cytokine multiplex method using Luminex technology. Differential gene expression profiling in cervical tumor was determined by microarray analysis and Real-time RT-PCR.

RESULTS

While levels of HPV-16 E7-specific IgG in vaginal wash were significantly higher in women undergoing HCC and HNN, the levels of the HPV-16 E7-specific IgA in vaginal wash of women with cervical cancer and cervical dysplasia were lower as compared to patients in HNN. Proinflammatory cytokines, such as IL-6 and IL-8, were dominant in vaginal washes of all subjects studied. However, no pattern of Th1-type and Th2-type cytokine induction was observed as demonstrated by protein analysis as well as differential gene expression profiling in cervical tumor.

CONCLUSIONS

These results suggest a selective down-regulation of local HPV-specific IgA responses in women with cervical cancer.

Detection of antibodies against a human papillomavirus (HPV) type 16 peptide that differentiate high-risk from low-risk HPV-associated low-grade squamous intraepithelial lesions

A nonapeptide (16L1) was derived from the human papillomavirus type 16 (HPV-16) major capsid protein and tested for detection of potential cross-reactive serum IgG and cervical IgA antibodies in low- and high-risk HPV-associated low-grade squamous intraepithelial lesions (LSIL) and cervical cancer patients by ELISA. The IgG response was similar in women with low-risk HPV-associated LSIL and controls (P=0.1). In contrast, more than 90 % of patients with high-risk HPV-associated LSIL were seropositive. Although tumours from cancer patients were all positive for the presence of high-risk HPV DNA, the level of seropositivity decreased significantly in this group (P<0.0001). Cervical IgA antibodies were also detected in a significantly high proportion of women with high-risk HPV-associated LSIL compared with controls. However, the proportion of IgA-positive patients was lower than the proportion of IgG seropositives. In conclusion, the 16L1 peptide appears to be a high-risk type-common epitope that induces cross-reactive antibodies in high-risk, but not low-risk, HPV-associated LSIL patients, allowing differentiation of high- and low-risk infected women at this stage of infection.

Lack of Serologic Evidence for Prevalent Simian Virus 40 Infection in Humans

BACKGROUND

Propagation of poliovirus in monkey kidney cells led to the inadvertent contamination of poliovirus vaccines with simian virus 40 (SV40) between 1955 and 1963. Recent studies using polymerase chain reaction-based strategies have detected SV40 DNA in a large number of tumor types. The finding of SV40 DNA in tumors from individuals who are too young to have been exposed to SV40-contaminated vaccines has led to the suggestion that SV40 has become a prevalent transmissible human pathogen. To test this hypothesis, we screened human sera for antibodies to SV40 using direct and competitive enzyme-linked immunosorbent assays (ELISAs).

METHODS

An ELISA was developed using recombinant SV40 virus-like particles (VLPs) and was validated using sera from naturally infected macaques. VLPs of SV40 and the related ubiquitous human polyomaviruses, JCV and BKV, were used to screen human sera to determine the prevalence of SV40, JCV, and BKV antibodies among a normal population of control subjects (n = 487) and among case patients with either osteosarcoma (n = 122) or prostate cancer (n = 90). A competitive ELISA in which sera were pre-adsorbed with each type of VLP was used to identify cross-reactive antibodies. Correlations of reactivity among the three polyomavirus types were calculated using the Spearman correlation coefficient. All statistical tests were two-sided.

RESULTS

BKV and JCV antibodies were prevalent in all case patients and control subjects examined. In contrast, only 6.6% (46/699) of serum samples were positive for SV40 antibodies by ELISA; however, none of these samples could be confirmed as having authentic SV40 antibodies following pre-adsorption with JCV or BKV VLPs.

CONCLUSION

These data indicate that some individuals have BKV and/or JCV antibodies that cross-react with SV40, but they do not provide support for SV40 being a prevalent human pathogen.

Mucosal IgG and IgA responses to human papillomavirus type 16 capsid proteins in HPV16-infected women without visible pathology

Human papillomavirus type 16 (HPV16) may infect the cervical epithelium without producing pathological changes for a long time. To investigate if mucosal antibodies are induced in HPV16-infected women without visible pathology, cervical mucus from HPV16-infected patients with and without evident pathology, along with mucus from uninfected women were analyzed for the presence of mucosal IgG and secretory IgA (sIgA) antibodies to HPV16 capsid proteins by ELISA. sIgA and IgG antibodies were found in a significantly higher proportion of infected patients compared with uninfected women (p < 0.0001). sIgA antibodies were present in 13.1% of infected patients without visible pathology, the proportion of positivity increased to 27.0% in patients with visible pathology (p = 0.001). Mucosal IgG response was observed in 6.5% of patients without and 27.5% of patients with visible pathology (p = 0.00005). The antibody mean signal strength was significantly higher in patients with than in patients without pathological evidence (p < 0.005). In conclusion, both sIgA and IgG are found in patients without pathological signs of infection, however, the response increases significantly in patients with pathological evidence, suggesting that the appearance of these changes might be associated with a more vigorous antibody-mediated mucosal reaction.

Characterization of IgA response among women with incident HPV 16 infection

Previous studies have characterized the prevalence and duration of serum IgG antibodies to human papillomavirus type 16 (HPV 16) in a well-studied cohort of college women, using viruslike particle- (VLP) based ELISAs. In this study IgA antibodies in cervical secretions and sera were examined using a newly developed capsomer-based ELISA and the patterns observed for serum IgG, serum IgA, and cervical IgA antibodies were compared. The median time to antibody detection from the first detection of HPV 16 DNA was 10.5 months for IgA in cervical secretions and 19.1 months for serum IgA. Serum IgA antibody conversion was observed less frequently and occurred later than IgA conversion in cervical secretions (P = 0.011) or serum IgG conversion (P = 0.051). The median time to antibody reversion, following seroconversion, was 12.0 months for IgA in cervical secretions and 13.6 months for serum IgA, whereas approximately 20% of women with serum IgG antibodies reverted within 36 months. Thus, the duration of IgA in cervical secretions and sera was shorter than the duration of serum IgG (P = 0.007 and 0.001).

Single-cell cytokine analysis allows detection of cervical T-cell responses against human papillomavirus type 16 L1 in women infected with genital HPV

Specific types of human papillomavirus (HPV) are known to play a causal role in the development of cervical cancer, with human papillomavirus type 16 (HPV-16) identified as the predominant type. Despite this, little is known about cervical immune responses to this pathogen. The aim of this study was to assess the feasibility of cervical cytobrush sampling and single-cell cytokine staining to investigate cervical lymphocyte-specific cytokine responses to HPV-16 antigens. Of eighteen women recruited into the study, five were HPV DNA positive at the cervix (current exposure) and a further five had circulating antibodies to HPV-16 (previous exposure). Cervical lymphocytes, isolated from the five HPV DNA-positive women, two HPV DNA-negative controls, and one woman with circulating HPV-16 antibodies were assessed for HPV-specific responses using intracellular staining for interferon-gamma (IFN-gamma) and interleukin-4 (IL-4). We demonstrate that both CD4(+) and CD8(+) cervical T lymphocytes, harvested from noninfected and infected subjects, produce these cytokines in response to nonspecific stimulation. However, antigen-specific (HPV-16 L1) IFN-gamma production by CD4(+) and CD8(+) cervical T lymphocytes is only detectable in women exposed currently or previously to HPV-16. This is the first time that antigen-specific cytokine responses of mucosal lymphocytes, obtained from a site of HPV infection, have been demonstrated. This finding clearly illustrates the use of intracellular cytokine staining for investigation of low precursor frequency single-cell antigen-specific responses in lymphocytes harvested from mucosal sites with HPV infection.

Immunity to oncogenic human papillomaviruses

The establishment of human papillomavirus (HPV) infection as a major cause of several human cancer forms, notably cervical cancer, has spurred development of prophylactic and/or therapeutic HPV vaccines for prevention of cervical neoplasia. Knowledge of the immunity to HPV forms the basis for such endeavors.

METHOD

A literature review of humoral and cellular immunity to HPV. The overview on human leukocyte antigen (HLA) and cervical cancer was expanded to a formal metaanalysis, where relevant articles were located by Medline search and citation analysis and graded by preassigned quality criteria on study design.

RESULTS

The antibody response to the HPV particle is dominated by a neutralizing antibody response to a typespecific, conformationally dependent immunodominant epitope. Vaccines based on viral particles lacking the viral genome (virus-like particles, VLPs) have been highly successful in preventing and treating HPV infection in several animal model systems. In humans, the serum antibody response to VLPs is stable over time, also after the HPV infection has been cleared, resulting in HPV serology being used as a marker of cumulative HPV exposure in spite of the fact that a significant proportion of HPV-exposed subjects fail to seroconvert. More than 90% of HPV infections will clear spontaneously. The factors that determine whether an HPV infection is cleared or persists and increases the risk for cancer are not known, but cellular immunity is implicated. Several HLA class II haplotypes are associated with cervical cancer: DQw3 increases and DR13 decreases the risk for cervical cancer in general (odds ratios (OR) and 95% confidence intervals (CI): 1.25(1.15-1.37) and 0.69 (0.56-0.85), respectively); DR15 increases the risk for HPV16-carrying cancer (OR: 1.47; CI: 1.20-1.81); and DR7 may be either protective or increase the risk. Most cervical cancers have downregulated the expression of at least one HLA class I antigen, whereas class II expression is increased in infected epithelium. A Th2 cytokine profile is associated with progression to cervical cancer. HPV-antigen-specific proliferative responses have been detected in many studies, although it is not entirely clear whether these responses are HPV type specific or may be cross-reactive between HPV types. Specific cytotoxic T lymphocyte (CTL) responses were originally reported in only a minority of infected subjects, typically cancer patients, but with advancing technology, specific CTLs can be stimulated from about half of the women with HPV-carrying disease. In animal model systems, CTL responses can mediate clearance.

CONCLUSION

The antibody response to HPV is a mediator of type-specific protective immunity, which forms the basis for prophylactic vaccine candidates. The cellular immunity to HPV is implicated as an important factor in cervical carcinogenesis, but the main targets and types of responses that mediate HPV clearance are not established.

The role of human papillomavirus vaccines in cervical neoplasia

Cervical cancer is the second most common cause of cancer-related death in women, in some developing countries accounting for the highest cancer mortality. The evidence for the association of high-risk human papillomavirus types with the aetiology of cervical neoplasia is firmly established, human papillomavirus being detected in virtually all cervical cancers. The risk of progression of precursor cervical intra-epithelial neoplasia lesions is associated with persistence of human papillomavirus infection. One strategy for the management of cervical neoplasia worldwide could be the development of prophylactic and/or therapeutic human papillomavirus vaccines. This chapter will discuss the natural history of human papillomavirus infection, viral immunity and the clinical course of resultant disease as the background to the effective design and use of human papillomavirus vaccines for protection or therapy. The progress of ongoing phase I and II clinical trials for several different vaccine preparations and the challenges for establishing their future use will be discussed.

Cervical secretory immunoglobulin A to human papillomavirus type 16 (HPV16) from HPV16-infected women inhibit HPV16 virus-like particles-induced hemagglutination of mouse red blood cells

Secretory immunoglobulin A (sIgA) antibodies are the first line of defence at the genital mucosa, and are thought to hinder viral infections by binding to conformational epitopes on the viral capsid. To investigate if cervical sIgA binds to conformational epitopes of the Human papillomavirus type 16 (HPV16), cervical mucus samples from 109 HPV16-infected patients were examined in a HPV16 virus-like particles-induced hemagglutination inhibition assay. 48 (44.1%) patients were able to inhibit hemagglutination. Inhibition of hemagglutination was associated with the presence of sIgA (P=0.001). In conclusion, naturally occurring cervical anti-HPV16 sIgA binds to and hinders conformational epitopes on the viral capsid, suggesting that these antibodies might have a neutralizing capacity.

Epidemiologic and mucosal immunologic aspects of HPV infection and HPV-related cervical neoplasia in the lower female genital tract: a review

Human papillomavirus (HPV) infections are known to play an important role in the pathogenesis of cervical neoplasia. Considering the morbidity and mortality of cervical cancer, infection with HPV can be regarded as a worldwide problem, especially in developing countries. Currently, many studies focus on the development of both prophylactic and therapeutic HPV vaccines. Crucial for these vaccination protocols to be successful is that they will result in a long-lasting ability to generate an immune response that will eliminate the virus. HPV transmission and subsequent infection is a local event in the lower female genital tract and therefore the efficacy of vaccines against this locally transmitted infection can be best assessed by parameters of local immunity. In this review we describe both the epidemiology of HPV-related cervical neoplasia and the general aspects of mucosal immunity in the female genital tract while focusing on the local humoral immunity in HPV-related cervical neoplasia.

Natural HPV immunity and vaccination strategies

BACKGROUND

the task of preventing premature death in women may be delivered by vaccinating against the high-risk papillomaviruses associated with various malignancies.

OBJECTIVES

we will discuss the immune mechanisms likely to be relevant to the control of an HPV infection in the cervix and assess the limited evidence for such immune recognition in the natural history of infection.

CONCLUSION

the next generation of vaccination strategies should include the use of HPV 16 early (E2 and/or E6 and/or E7) and late gene targets (L1 and L2) expressed as VLPs with their clinical and immunological evaluation aimed at therapy as well as prophylaxis. Important clinical efficacy assessment may be deliverable in relatively short-term studies by targeting patients with HPV 16 associated vulval intraepithelial neoplasia.

Trends over time in the incidence of cervical neoplasia in comparison to trends over time in human papillomavirus infection

INTRODUCTION

The establishment of human papillomavirus (HPV) infection as a major cause of cervical neoplasia has resulted in major efforts to develop prophylactic HPV vaccines for prevention of cervical neoplasia. Cervical cancer and the other HPV-associated cancers constitute a major public health burden and eradication of the major causative infection is certainly the most appealing long-term preventive measure. Nevertheless, the effects of preventive HPV vaccination will need to be estimated and compared for (cost-) efficacy with other primary prevention and with secondary prevention programs. However, estimating the effects of preventing a causative exposure is complicated when the exposure is a transmissible infection. The spread of the epidemic is dynamic and may change over time depending e.g. on the changes in human behavior. Depending on the circumstances, prevention of an infection may have either greater or lesser effects than the prevention of a non-infectious exposure. Estimating the time trends in HPV infections and the underlying trends in the risk of cervical neoplasia is important for estimating effects of interventions.

METHOD

A literature review on recent evidence on time trends in cervical neoplasia, compared with evidences on time trends in HPV infections and interactions between different types of HPV infections.

RESULTS

In Finland, there has between 1991 and 1995 been a 60% increase in the incidence of cervical cancer among women <55 years of age. Trends in detection rates of cervical cancer precursor lesions are consistent with an increase in the background cervical cancer risk. From the 1960s to 1980s, there has been a major increase in HPV seroprevalences over time in the Nordic countries. Increasing trends are also seen for other sexually transmitted diseases and smoking. Several studies indicate the existence of interaction between benign and oncogenic HPV types, thus making the relationship between the incidences in HPV infections and in cervical neoplasia complex.

CONCLUSION

The increase in cervical cancer is paralleled by increases in HPV infection, other STDs and smoking and changes in screening practices, all of which may have contributed. Prediction of the effect on cervical cancer incidence of changes in HPV incidences is complicated by the existence of several risk factors, the protective effect of screening and by the population dynamics of HPV infections.

The serological response to papillomaviruses

The antibody response to papillomaviruses is a key determinant of protective immunity. HPV serology is also an important epidemiological tool for the assay of past and present HPV infections and for prediction of HPV-associated cancers and their precursor lesions. This review focuses on the assay of antibody responses to the HPV capsid, its use as a marker of cumulative HPV exposure and surveys how HPV seroepidemiology has been used to elucidate the spread of HPV infection in various populations, the natural history of HPV infection and that exposure to HPV is associated with increased risk for several human cancers.

Cytokine and immunoglobulin concentrations in cervical secretions: reproducibility of the Weck-cel collection instrument and correlates of immune measures

Elucidation of local immune response at the cervix is important for understanding and evaluating STD vaccine approaches currently being proposed. However, no well-validated method exists for the collection of cervical secretions for evaluation of cervical immune response. The purpose of this study was to determine the reproducibility of the Weck-cel sponge used to collect cervical secretions for immunological assessment. Additionally, it was possible to examine correlates of immunity as part of our investigation. Two cervical secretion specimens were collected sequentially from each of 120 women using Weck-cel sponges. Cervical secretions were collected prior to Pap smear sampling to avoid blood contamination. At the laboratory, the duplicate specimens were weighed and tested in replicate wells to determine the concentration of two cytokines (IL-10 and IL-12) and two immunoglobulin isotypes (IgG and IgA). IL-12, total IgG, and total IgA showed a strong correlation between samples from the same woman ranging from 0.78 to 0.84. Kappa coefficients obtained after categorizing assay results ranged from 0.62 to 0.67. Variance components analysis suggested that 69% to 85% of the variance observed was accounted for by between-women variance, with the remaining variability attributed to variation between samples collected from the same woman. IL-10 results were less reproducible than those obtained from the other assays examined, suggesting problems with the assay used to measure this cytokine rather than with the Weck-cel sampling instrument. Various factors were found to significantly correlate with cytokine and immunoglobulin measures at the cervix. Age and reproductive status were associated with all four immune measures; women over 50 years of age and those who were postmenopausal had increased concentrations of IL-10, IL-12, IgG, and IgA. Hemoglobin concentrations were positively correlated with IgG and IL-10 concentrations, but not with IgA or IL-12 concentrations, suggesting local production of IgA and IL-12. The concentration of all immune measures decreased with increasing volume of collection. No significant association was observed between time from collection to freezing of specimens and concentrations of cytokines or immunoglobulins. Overall, our data suggest that measurement of immunological parameters in cervical secretions collected using Weck-cel sponges are reproducible. In addition, various correlates of cytokine and immunoglobulin concentrations were identified.

High risk genital papillomavirus infections are not spread vertically

The Medline-indexed literature on risk factors for HPV infection and HPV transmission is critically reviewed. Principles for assay validation and interpretation, reliability of different study designs and principles for interpretation of conflicting reports are discussed. The conclusions arrived at can be summarised as: (1) There is overwhelming epidemiological evidence that the only quantitatively important mode of transmission of infection with oncogenic genital HPV types is sexual. (2) There is also evidence that benign genital HPV types can be transmitted sexually, but the epidemiological data on the benign virus types are less extensive and less clear. (3) Perinatal HPV transmission is unequivocally demonstrated only for the rare disease juvenile respiratory papillomatosis.

Collection of cervical secretions does not adversely affect Pap smears taken immediately afterward

Collection of cervical secretions for local immunological assessment requires that the secretions be collected prior to the Pap smear to avoid contamination with blood. The objective of the present study was to determine whether gentle collection of cervical secretions prior to a Pap smear collection influences the quality of the Pap smear. A total of 266 women were recruited. Half of the participants were assigned to collection of cervical secretions prior to Pap smear collection with Weck-cel sponges. The remaining half had only the Pap smear collection performed. Pap smear slides were reviewed and evaluated for quality by the Bethesda System adequacy criteria without knowledge of randomization. The proportions of limited or inadequate slides in the two study groups were compared by using the Pearson chi-square test. No significant differences were observed between the two study groups when overall Pap smear quality was evaluated (P = 0.29). Comparison of the two study groups with respect to individual adequacy criteria, including presence of air drying artifact, presence of obscuring blood, absence of metaplastic or endocervical cells from the transformation zone, scant cellularity, and presence of obscuring inflammatory cells, also revealed no significant differences between the two study groups. Results from the present study suggest that the collection of cervical secretions with Weck-cel sponges does not adversely impact the quality of subsequently obtained Pap smears.

Immunoglobulin-A and -G responses against virus-like particles (VLP) of human papillomavirus type 16 in women with cervical cancer and cervical intra-epithelial lesions

Immunoglobulin-A and -G (IgA and IgG) responses against HPV-16-like particles (VLP) were tested by ELISA in 104 women with cervical abnormalities, 26 atypical cells of undetermined significance (ASCUS) and 14 cytologically normal women with HPV DNA. As controls, 130 age-matched cytologically normal women with no HPV DNA were selected from the population in which the cases were generated. The existence of HPV DNA in cervical samples was tested by a PCR-based method. The normal women positive with HPV-16 DNA were followed up at 4- to 7-month intervals for 16 to 24 months. IgA and IgG antibodies against HPV-16 VLP were frequently detected in these women repeatedly positive with HPV-16 DNA, suggesting that persistent HPV infection is crucial for effective antibody responses against the viruses. IgA response appears earlier and persists longer than IgG response. Women with HPV DNA of types 16, 31/33/35, 58 and unknown types showed significantly higher seropositivity for both IgA and IgG antibodies than the controls (p < 0.05 for both). No significant seropositivity for IgA or IgG was detected in the HPV-18/45-DNA-positive group. HPV 31/33/35, 58 appear to be types close to HPV 16, whereas HPV 18/45 appears to be distinct from HPV 16 in antigenicity. IgA and IgG responses against HPV-16 VLP were more frequently observed in women with normal cervices with HPV DNA, ASCUS, HSIL and cervical cancer than in the controls. Strong IgA and IgG responses depended on HPV-16 infection in HSIL and cervical cancer, but there was no correlation between the serological responses and the status of HPV DNA in ASCUS and LSIL. Antibody positivity reflects persistent viral infection that may increase the risk for malignant progression of the cervix. This serological assay using HPV-16 VLP may therefore be useful as a new diagnostic tool supplementing cervical cytological tests.