Detection of IgA antibodies against human papillomavirus in cervical secretions from patients with cervical intraepithelial neoplasia

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.

Effectiveness and immune responses of focused ultrasound ablation for cervical intraepithelial neoplasia

PURPOSE

To investigate the safety, efficacy, and the immune responses of focused ultrasound in cervical intraepithelial neoplasia (CIN).

METHODS

Patients with biopsy-confirmed CIN were recruited for focused ultrasound treatment and asked to return during 3-6 and 6-12 months post-treatment to receive cervical cytology, high-risk human papilloma virus (HPV) detection, and colposcopy. The effective rate was evaluated within 3-6 months, whereas the recurrence rate was evaluated within 6-12 months. Cervicovaginal lavage and cervical tissue were sampled before and 3-6 months after treatment. The expression of interferon gamma (IFN-γ), endoplasmic reticulum aminopeptidase 1 (ERAP1), human leucocyte antigen I (HLA-I), cluster of differentiation 4 (CD4), and cluster of differentiation 8 (CD8) in the cervical tissue were observed by immunohistochemistry. Immunoglobulin A (IgA) and interleukin 10 (IL-10) levels in the cervicovaginal lavage were detected by enzyme-linked immunosorbent assay. Comparisons were made in immune analyte levels before and after treatment.

RESULTS

We analyzed the results of 154 patients. The effective rate at 3-6 months was 96.8%. The recurrence rate at 6-12 months was 2.0%. The eradication rate of HPV was 72.4% at 3-6 months and 81.0% at 6-12 months. No serious adverse reactions and complications were observed. After treatment, a higher expression of ERAP1 was observed (p < 0.05). Significant down-regulation of IgA and IL-10 were detected (each p < 0.05). However, the expression of CD4, CD8, HLA-I, as well as the release of IFN-γ, did not reach statistical significance (each p > 0.05).

CONCLUSIONS

Focused ultrasound is an effective and safe therapy for treating CIN, which could improve the local immune milieu of the cervix to some extent.

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.

Role of Immune Response in the Prognosis of Carcinoma of the Uterine Cervix: Can in Vitro Analysis Provide a better Framework for more Effective Management?

Cancer of the uterine cervix is the single largest female malignancy in India and also remains a major problem facing oncologists in other parts of the world. While advances in radiation therapy and surgical techniques have made the treatment of cervical carcinoma impressive, limitations to successful management still remain. In fact, the 5-year survival rate, stage for stage, has not improved in the United States or world wide in the past 40 years. With an estimated half a million women developing this disease annually, this lack of improved survival poses an international unresolved health problem. Immune response has been shown to be a major factor involved In the course of the disease for this cancer. Immunologic monitoring was also shown to be of effective value in assessing the prognosis for cervical carcinoma. We studied the various immunologic abnormalities in cervical cancer, the effects of radiation therapy on immune function, prospects of an immunologic staging system, the relationship between human papillomavirus infection and the Immune response, and the possibility of using in vitro Immunologic assessment to provide a better framework for more effective management of cancer of the uterine cervix.

Mecanismos de resposta imune às infecções

O conhecimento dos principais mecanismos de defesa imune contra os diversos agentes infecciosos permite a compreensão da patogênese das doenças infectoparasitárias e das várias estratégias do hospedeiro e do parasita. O sistema imunológico atua numa rede de cooperação, envolvendo a participação de muitos componentes estruturais, moleculares e celulares. Nesse cenário encontra-se o delicado equilíbrio entre a saúde e a doença, em que tanto a deficiência quanto o exagero resultam em dano tecidual. Este artigo explora esses aspectos e algumas abordagens terapêuticas que surgem desse entendimento.

Immunotherapy of human cervical high-grade cervical intraepithelial neoplasia with microparticle-delivered human papillomavirus 16 E7 plasmid DNA

OBJECTIVE

The purpose of this study was to evaluate the safety of the administration of a bacterial expression plasmid encoding a 13 amino acid sequence that is highly homologous with human papillomavirus E7 within poly (lactide-co-glycolide) microparticles (ZYC101) in women with HLA A2+ antigen and persistent cervical intraepithelial neoplasia grade 2/3 and human papillomavirus 16.

STUDY DESIGN

Fifteen women entered an institutional review board-approved dose-escalating phase I study with the use of three levels of blood monitoring and urine studies, Papanicolaou tests, and colposcopy. Escalation required no serious adverse events. Immunologic responses were evaluated in peripheral blood with the use of human papillomavirus peptide-stimulated interferon gamma enzyme-linked immunosorbent assay for T-cell reactivity. In cervical secretions, immunoglobulin A anti-human papillomavirus 16 E2 concentrations were measured. Three doses every 3 weeks were followed 4 weeks later by surgical excision.

RESULTS

No serious adverse events occurred. Five women had complete histologic responses; 11 women had human papillomavirus-specific T-cell responses. Four of five complete histologic responses developed immunoglobulin A anti-E2-specific antibody.

CONCLUSION

ZYC101 warrants further investigation because of a 33% complete histologic responses, a 73% immunologic response, and no serious adverse events.

Antibodies against human papillomavirus type 16 and 18 E6 and E7 proteins in cervicovaginal washings and serum of patients with cervical neoplasia

Serum antibodies against the E6 and E7 proteins of human papillomavirus (HPV) 16 and 18 are associated with cervical cancer. The aim of this study was to investigate the presence of local antibodies against HPV in cervicovaginal washings (CWs). In this study antibodies against the native HPV16 and HPV18 E6/E7 proteins were detectable in CWs (48%) and sera (29%) from patients with cervical cancer (n = 21) utilizing a sandwich protein enzyme-linked immunosorbent assay (ELISA). In paired CWs and sera from patients with cervical intraepithelial neoplasia (n = 38) and from healthy women (n = 22) no antibodies against these proteins were found. In 10 of 11 patients, the antibody response corresponded with the HPV type in the cervical smear and/or tumor tissue, which indicates the HPV type specificity of the assay. In 7 of 11 patients with antibody reactivity against HPV16 or HPV18 E6 and/or E7 proteins a higher level of antibody reactivity in the CWs than in the paired serum samples was found at similar inputs of total IgG. This suggests that the antibodies in the CWs against the investigated HPV proteins in these patients were locally produced.

Antibodies against human papillomavirus (HPV) type 16 and 18 E2, E6 and E7 proteins in sera: correlation with presence of papillomavirus DNA

Human papillomavirus (HPV) infection is associated with cervical cancer. The E2 and E1 papillomavirus proteins are expressed at the early stage of infection and regulate DNA replication. The E2 protein activates and represses transcription from different HPVs promoters. At some stage when viral DNA gets integrated into the cellular genome, the E2 gene is disrupted or inactivated. This event leads to a derepression of the E6 and E7 viral oncogenes. These viral proteins are required normally for the maintenance of the malignant phenotype. Therefore, the E2, E6, and E7 proteins are present in all patients infected by papillomavirus. In this study, the association of antibody levels against E2, E6, and E7 proteins of HPV types 16, 18, and 6 was determined in relation to the presence of HPV DNA at the initial stages of HPV infection. Serum samples from 172 women with HPV infection, determined by Papanicolau (Pap) smears and colposcopy, were tested. Elevated antibody titers against E2 protein from the HPV 6 and HPV 16 were detected in 46.42 and 66.96% of the patients, respectively. Antibodies against the E7 and E6 proteins of HPV 16 were found in 51.78 and 36.60% of the patients, respectively. Antibodies against the E6 and E7 proteins of HPV 18 were 35 and 45%, respectively. A statistical difference was found for antibody titers against the E2, E6, and E7 proteins between patients with papillomavirus DNA and controls cases who had no cytological abnormalities and no HPV DNA. Sera titers were 1/500 for patients HPV positive and 1/50 for control individuals. Antibodies titers against E6 and E7 proteins were also examined in patients at 6 and 24 months after cryosurgery. In these patients, a slight decrease in the antibody level against the E2, E6, and E7 proteins was found. No correlation was found between age and number of sexual partners, with serum positivity to the E2, E6, and E7 papillomavirus proteins. These data suggest that antibodies against the E2, E6, and E7 proteins are good candidates for use as markers for monitoring cervical HPV infections.

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.

IgG antibodies against human papillomavirus type 16 E7 proteins in cervicovaginal washing fluid from patients with cervical neoplasia

Little information is available about the cervicovaginal mucosal antibodies against human papillomavirus (HPV) proteins. In this study specific IgG antibodies against HPV 16 E7 protein were determined in paired samples of cervicovaginal washing fluid and serum from patients with cervical cancer (n = 22), cervical intraepithelial neoplasia (CIN) (n = 38), healthy individuals (n = 22), and serum from children (n = 41) by a radioactive immunoprecipitation assay (RIPA). HPV 16 E7 specific IgG antibodies were found in cervicovaginal washings (n = 8) and in sera (n = 8) of the patients with cervical cancer. About 60% of the patients with HPV 16 positive cervical cancer had HPV 16 E7 specific IgG antibodies. Titration studies showed that the IgG antibody reactivity in cervicovaginal washings was higher than in the paired serum samples of six patients with cervical cancer (P < 0.001). In the CIN group we found no IgG reactivity in the serum, but in five patients we found a low IgG reactivity in the cervicovaginal washings. No IgG reactivity was found in cervicovaginal washings and sera from healthy individuals and sera from children. HPV 16 E7 specific IgG antibodies seem to be locally produced in a number of patients with HPV 16 positive (pre)malignant cervical lesions. For more definitive evidence for the local production of these antibodies immunostaining should be performed to demonstrate the presence of specific anti-HPV 16 E7 IgG producing plasma cells in the cervical epithelium.

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

To investigate whether cervical mucus antibodies against human papillomavirus (HPV) capsids are associated with the detection of HPV DNA or HPV-related cytological diagnoses, 611 samples of cervical secretions from 359 women referred to a colposcopy clinic were tested by an enzyme-linked immunosorbent assay for the presence of immunoglobulin A (IgA) antibodies against HPV capsids of HPV type 16, 18, or 33 and for the presence of cervical HPV DNA by PCR. Among subjects with at least one cervical sample positive for HPV type 16 (HPV-16) DNA, 28.1% also had at least one HPV-16 IgA-positive cervical sample (odds ratio [OR] = 2.9; P = 0.0003). IgA to HPV-18 was also more common among HPV-18 DNA-positive subjects (OR = 3.1; P = 0.0325) and IgA to HPV-33 was more common among HPV-33 DNA-positive subjects (OR = 4.2; P = 0.0023). Cervical IgA antibodies to HPV-16 were also more common among patients with cervical intraepithelial neoplasia, particularly among patients with cervical intraepithelial neoplasia grade I (P < 0.0005). The data indicate that an HPV type-restricted IgA antibody response against HPV capsids is detectable in cervical mucus and is associated with a concomitant cervical HPV infection.

Prevalence of serum antibodies to synthetic peptides to HPV16 epitopes among Indian women with cervical neoplasia

Serum samples from 38 Indian women with cervical intraepithelial neoplasia (CIN) and cancer along with 20 control women were analysed for IgG antibodies against a panel of four synthetic peptides derived from early and late gene open reading frames of HPV16. The cervical tissue samples from these patients were also subjected to PCR in order to detect the presence of human papilloma viruses (HPVs) type 6, 11 and 16 DNA, using a set of primers for the E6 open reading frames in order to establish the acquisition of HPV infection. E2, E6 and L1 peptides of HPV16 were found to be highly reactive with the patients' sera, and a significant prevalence of antibodies to E6, E2 and L1 (P < 0.01) was observed among women with CIN, while antibodies to E6 peptide were only significantly elevated (P < 0.01) among women with cervical invasive carcinoma. Furthermore, there was good agreement between the development of the E6 antibody response and the presence of HPV16 E6 DNA among women with CIN and cervical invasive carcinoma as shown by high values of the kappa coefficient (0.7-1.0). The study clearly revealed a strong agreement between two assay methods defining unambiguous immunogenic B-cell epitopes on synthetic peptides to early and late gene open reading frames of HPV16 which could be used in HPV peptide serology. As such, single or combination of peptides in HPV peptide serology can be used as a screening tool to identify HPV-associated cervical lesions.

Seric and local antibodies against a synthetic peptide of HPV16

An ELISA method was used to detect IgG and IgA directed against a synthetic peptide derived from the E2 ORF of the human papillomavirus (HPV) 16 in sera and in cervico-vaginal secretions from 20 women without evidence of HPV infection and from 41 women with histological diagnosis of HPV infection. The proportion of IgA positive sera (63.4% in the case-group vs. 20.0% in the control-group) and secretions (48.8% in the case-group vs. 15.0% in the control-group) was significantly higher in women with HPV infection and seemed to increase with the severity of the cervical lesion. Such a difference was not found for specific IgG. Comparing, for each patient, the antibody level in the serum and in the secretions, we found that the amount of IgA was at mean 2.4 times higher in the sera than in the secretions.

Human papillomavirus DNA and anti-HPV secretory IgA antibodies in cytologically normal cervical specimens

Cervical specimens collected from 163 cytologically healthy women were screened for the presence of human papillomavirus (HPV) DNA and anti-HPV secretory IgA antibodies. HPV DNA was detected by a general primer mediated polymerase chain reaction (PCR), which amplifies a conserved region from the L1 ORF of genital HPVs. The PCR products were typed by restriction enzyme digestion. A total of 35 samples (21.5%) were positive for HPV DNA (13 samples for HPV 6, 6 for HPV 16, 3 for HPV 18, and 13 for untypeable HPV X). HPV DNA positivity was significantly higher among women under 25 years of age (34.8%) than among the older patients (12.4%) (P < 0.001). An enzyme-linked immunosorbent assay (ELISA) using synthetic peptide antigens was carried out to detect local secretory IgA antibodies against the following HPV specific antigens: HPV 16 E2, HPV 16 E7, HPV 16 L1, HPV 16 L2, and HPV 11 L2. Thirty-four secretions (20.9%) were found to react with at least one of the oligopeptides. Anti-HPV IgA positivity was the highest among women aged 25-32 years, and it was significantly lower in both the younger and the older age groups (P < 0.05). Correlation between HPV DNA and anti-HPV IgA detection was rather weak: anti-peptide IgA positivity was 34.3% (12 of 35) among HPV DNA positive patients compared to 17.2% (22 of 128) among HPV DNA negative women (P < 0.05). The fluctuating course of latent HPV infections should be considered in evaluating the low level of correlation between HPV DNA and anti-HPV IgA positivity.

Pathogenesis of genital HPV infection

Clinical, subclinical, and latent human papillomavirus (HPV) infections are distinguished from HPV-associated neoplasia. Besides HPV additional cofactors are necessary to transform HPV infected tissue to intraepithelial or invasive neoplasia. Risk factors for the presence of HPV are high number of sexual partners, early cohabitarche, young age at first delivery, suppression and alteration of immune status, young age and hormonal influences. While the fact of a high number of sexual partners exclusively increases the risk of HPV infection, it is not known whether the other factors lead to either an increased risk for HPV infection and/or to HPV-associated neoplasia. Subclinical and latent genital HPV infections are highly prevalent. The prevalence rate depends on the sensitivity of the HPV detection system used, on age and sexual activity of the population screened, and on the number of subsequent examinations performed for each subject. Sexual transmission is the main pathway for genital HPV's, however, vertical, peripartal, and oral transmission are also possible. Seroreactivity against genital HPV may be due to an active infection or the result of contact with HPV earlier in life. Antibodies against the HPV 16 E7 protein indicate an increased risk for cervical cancer. Compared with humoral response cellular immune response is probably more important for regression of genital HPV infection: impaired cellular response is characterized by depletion of T helper/inducer cells and/or Langerhans cells and impaired function of natural killer cells and/or the infected keratinocyte. In condylomata replication and transcription of viral nucleic acids and antigen production coincide with cellular differentiation. However, the interaction between HPV and the keratinocyte on a molecular level in subclinical and latent disease is not well understood. Regression or persistence of subclinical and latent genital HPV infections as observed in longitudinal investigations show a constant come-and-go of HPV presence. Subclinical or latent cervical infections with high-risk HPV types (such as HPV 16 and 18) have an increased risk for the development of HPV-associated neoplasia.

Antibodies against papillomavirus antigens in cervical secretions from condyloma patients

Samples of cervical secretions and serum from 30 women with genital condylomas and 30 age-matched controls were tested for the presence of immunoglobulin A (IgA) and IgG antibodies against a panel of papillomavirus-derived antigens. The same cervical samples were also analyzed for presence of human papillomavirus (HPV) DNA by Southern blotting and polymerase chain reaction. By Southern blotting HPV DNA was detected in 8 of 30 patients with condylomas and 2 of 30 controls, and by the polymerase chain reaction HPV DNA was detected in 14 of 30 patients with condylomas and 5 of 30 controls. A total of 18 of 29 patients with condylomas and 8 of 28 controls had IgA antibodies in cervical secretions to an E2 synthetic peptide, and 17 of 29 patients with condylomas and 5 of 28 controls had local IgA antibodies to an E7 peptide (P < 0.025 and P < 0.005, respectively). The results suggest that measurement of local antibody production against selected HPV antigens may be useful in the study of HPV immunology and, possibly, for the diagnosis of HPV infection.

Towards vaccines against human papillomavirus type-16 genital infections

Human papillomavirus type-16 (HPV-16) is strongly associated with cervical carcinoma and cervical intraepithelial neoplasia. It may soon be possible to develop prophylactic vaccines designed to induce neutralizing antibodies to HPV-16 virions in genital secretions and therapeutic vaccines to induce cytotoxic T-cell responses against HPV-16 early proteins in cervical intraepithelial neoplasia and cervical cancers. Although significant advances have been achieved, problems remain before such vaccines can be used routinely.

Pre- and posttreatment serum antibody responses to HPV 16 E2 and HSV 2 ICP8 proteins in women with cervical carcinoma

Serum antibodies to early proteins of human papillomavirus type 16 (HPV 16 E2 protein) and herpes simplex virus type 2 (HSV 2 ICP8) can be measured by ELISA. In the serum of 122 newly diagnosed cervical carcinoma patients and age-matched controls, enhanced IgA antibody levels to an HPV-16 E2 protein derived peptide no. 245 indicated a 9.5-fold (95% confidence limits 2.8-57.2) relative risk of cervical carcinoma. No significant risk was found with a corresponding HPV 6 E2 peptide or HSV 2 ICP8. To evaluate the HPV 16 E2 peptide as a possible tumor marker for cervical carcinoma serial postoperative serum samples were tested from 27 women with cervical carcinoma. Antibody responses to the HPV 16 E2 peptide depended on the clinical stage. Stage I and II patients showed decreasing posttreatment IgA and/or IgG antipeptide antibody levels. Stage III and IV patients initially showed decreasing antipeptide antibody levels followed by increasing levels. These patients also showed increasing IgG antibody levels to the HSV 2 ICP8. However, increasing antibody levels to the HPV 16 E2 peptide indicated significantly (P less than 0.05) worse 2-year disease free survival (recurring disease) than did stable or decreasing antibody levels. The results suggest that serum antipeptide antibodies to the HPV 16 E2 peptide no. 245 can be used for the monitoring of cervical carcinoma.

Seroreactivity to HPV-16 proteins in women with early cervical neoplasia

Although serological reactivity to human papillomavirus type 16 (HPV-16) proteins has been demonstrated in patients with invasive cervical carcinoma, the degree of seroreactivity to these proteins in women with preinvasive disease and its relationship to the HPV type associated with the disease are unclear. We obtained sera from 27 women undergoing cone biopsy for cervical precursor lesions and 22 controls and analyzed seroreactivity by Western blot to fusion proteins containing portions of the HPV-16 E4, L1 and L2 open-reading frames (ORFs). Positives were analyzed by scanning densitometry and intensity values for each case plotted relative to controls. Cervical biopsy specimens from patients were analyzed for HPV-16 nucleic acids by DNA.DNA in situ hybridization. Mean intensity values for seroreactivity to the pATH-E4 protein approached significance (P = 0.058) and a significantly higher proportion of cases vs controls registered values over 4.0 for pATH-E4 (26% vs 4.5%; P = 0.04) and pATH-L2 (48% vs 18%; P = 0.03) proteins. A significantly higher mean intensity value for E4 was observed for cases containing HPV-16 DNA vs HPV-16 negative cases or controls. Thus, seroreactivity to HPV-16-derived proteins may be more common in women with preinvasive cervical disease, and for some protein targets (E4) may indicate a relatively type-specific response.

Antigenic and immunogenic epitopes shared by human papillomavirus type 16 and bovine, canine, and avian papillomaviruses

All types of papillomaviruses (PV) share common, so-called group-specific epitopes. To identify the major group-specific epitopes, we immunized 26 guinea pigs or rabbits with purified bovine PV type 1 (BPV), canine PV, or avian PV from the common chaffinch. The resulting hyperimmune sera, as well as a commercially available rabbit antiserum to BPV and seven monoclonal antibodies to BPV, were tested in an enzyme-linked immunosorbent assay with a set of 66 overlapping 20-amino-acid peptides representing the complete sequence of the major capsid proteins (L1 and L2) of human PV type 16 (HPV 16). Sera from the same animals before immunization were used as controls. The minimal reactive epitopes within each peptide were further characterized by testing of truncated peptides. The cross-reactive epitopes were clustered in two regions of L1, an internal region (at positions 171 to 235), which contained three epitopes, and the more reactive region at the carboxy terminus (at positions 411 to 475), which contained six epitopes. The most reactive of the HPV 16 broadly cross-reactive epitopes was a carboxy-terminal epitope which had the sequence DTYRF and which reacted with nine of the antisera to BPV, canine PV, or avian PV, with the commercially available rabbit antiserum to BPV, and also with a mouse monoclonal antibody to BPV. Antipeptide antisera to all of the HPV 16 L1 peptides and to the most antigenically reactive of their truncated analogs were made in guinea pigs. Antipeptide antisera reactive with BPV were obtained for three of the cross-reactive epitopes, and one of these antisera allowed highly sensitive detection of group-specific PV antigen by immunoperoxidase staining.

Pathobiology of papillomavirus-related cervical diseases: prospects for immunodiagnosis

In recent years, the relationship between human papillomaviruses (HPV) and genital neoplasia has been explored intensively, and a molecular basis for the role of HPV in the genesis of these diseases has been convincingly demonstrated. These findings have provided justification for efforts to apply this molecular information to the early detection and possible prevention of HPV-related neoplasia. The technology of detecting viral nucleic acids in genital fluids brought with it initial hopes that it would serve to identify women at risk for having or developing precancers or cancers of the cervix. Subsequent studies, however, have demonstrated limitations of the technology for predicting future disease. Recently, molecular immunology has complemented these prior efforts, with the intent to identify serological indices of exposure to HPV and perhaps delineate individuals at risk. The molecular basis for this approach, its limitations, and future prospects for immunodiagnosis are the subject of this review.

Local immunity and the uterine cervix: implications for cancer-associated viruses

Studies of cervical secretions as well as cells composing the endocervix have provided evidence for a functional and potentially important immunological system in the mucosa of that organ. The availability of the tools of cell biology as well as three agents that may be used as probes to infect cervical mucosa experimentally has made possible a detailed approach to define the structural and functional characteristics of local cervical immunity. A long-term goal of these studies is to determine how the cervical immune response may be regulated to reduce local viral replication and virus-associated diseases. With Langerhans cells for antigen presentation, cervical immune responses generally remain detectable for more than 30 days, are predominantly of the IgA isotype, can be influenced by estrogen or progesterone, and are best elicited by local rather than systemic exposure to antigen. Cervical immune responses to the human papillomaviruses (HPV) are of particular importance in this regard because this virus is associated with cervical neoplasia. While responses in serum to HPV-16 proteins L1, E4, and E7 has been found in up to 78% of persons with HPV-associated cervical neoplasms, data showing that a local response of comparable frequency consistently occurs have yet to be confirmed. The current status of local HPV-16-specific immunoglobulin as a potentially useful indicator of HPV-16-related infection or pre-cancer is controversial, and is confounded by several potentially important factors, including patient age, estrogen/progesterone level, smoking status, and sample admixture with serum immunoglobulin.

Mapping of linear epitopes of human papillomavirus type 16: the E1, E2, E4, E5, E6 and E7 open reading frames

Certain types of human papillomavirus (HPV), especially HPV type 16, are associated with proliferative lesions of the cervix uteri that can progress to malignancy. In order to map the linear epitopes of the HPV-encoded proteins, we have synthesized the predicted amino acid sequences of the open reading frames (ORFs) in the early region of HPV 16, as a set of 94 synthetic 20-residue peptides overlapping each other with 5 amino acids. The peptides were tested for reactivity with IgA, IgG and IgM antibodies in the sera of 30 patients with HPV 16-carrying cervical neoplasia. The EI ORF had only low immunoreactivity, but several relatively minor epitopes were identified in the carboxyterminal part. The E2 ORF was found to contain several epitopes that were highly immunoreactive with a majority (up to 87%) of the cervical cancer patients' sera. The E4 ORF had one major, regularly IgA- and IgG-reactive epitope, whereas the E5 and E6 ORFs had only a few minor epitopes. The E7 ORF had several epitopes that were highly immunoreactive, but only with a minority of patients' sera. The 10 most immunoreactive peptides were also analyzed for immunoreactivity with 60 control sera, of which 22 were derived from patients with parotid gland tumors and 38 were derived from healthy volunteers. Most of the peptides were also immunoreactive with the control sera. However, the IgA antibodies, and to some extent the IgG antibodies, were found at much lower levels among the controls.

Mapping of linear epitopes of human papillomavirus type 16: the L1 and L2 open reading frames

Certain types of human papillomavirus (HPV), notably HPV type 16, are associated with flat or inverted proliferative lesions of the cervix uteri that can progress to malignancy. As a first step towards the serological study of the epidemiology of HPV, we have synthesized the entire amino acid sequences of the 2 major viral capsid proteins of HPV type 16, L1 and L2, as a set of 66 synthetic 20-residue peptides with an overlap of 5 amino acids. The peptides were tested for reactivity with IgA, IgG and IgM antibodies in the sera of 30 patients with HPV-16-carrying cervical neoplasms. Both IgG and IgM antibody responses were detected, but most of the reactivity found was of the IgA class. The most immunoreactive peptides were further analyzed for reactivity with sera from 22 patients with parotid gland tumors and with sera from 38 healthy individuals. The L2-encoded protein contained only one major linear epitope, which was not specific for HPV-16-carrying neoplasms. In contrast, the L1-encoded protein contained several epitopes that were regularly immunoreactive with antibodies present in the sera of patients with HPV-16-carrying cervical neoplasms, but only rarely so in the sera of patients with other tumors or of healthy individuals.

Serological responses to papillomavirus group-specific antigens in women with neoplasia of the cervix uteri

Certain types of human papillomaviruses have been linked to the development of carcinoma of the cervix uteri. We have analyzed 114 serum specimens from women with cervical intraepithelial neoplasia (CIN) or carcinoma of the cervix uteri for the presence of serum antibodies against purified, disrupted bovine papillomavirus (BPV). The titers of immunoglobulin A (IgA) antibodies against BPV were slightly elevated (P less than 0.025) in the sera from CIN or cervical carcinoma patients compared with the titers of 139 serum specimens from sex- and age-matched healthy controls. In contrast, both the IgG and IgM serum antibody titers against BPV were significantly decreased for CIN and cervical carcinoma patients compared with those of healthy controls (P less than 0.001 and P less than 0.005, respectively). These results suggest that the difference between IgA and IgG or IgM antibodies to papillomavirus group-specific antigens may represent interesting serological parameters that could possibly be used in the epidemiologic study of women at risk for CIN.

Humoral assays of human sera to disrupted and nondisrupted epitopes of human papillomavirus type 1

The use of different assay systems and the disparity in results obtained has meant that we have little understanding about the role played by the humoral response during human papillomavirus (HPV) infection. Human antibody responses have so far appeared to be largely directed against the major capsid protein, L1. This protein possesses both type-specific and type-common antigenic determinants but it is not known which of these is important in vivo during the natural course of infection. In this study humoral responses of 83 individuals to purified HPV 1 virions were tested in three types of antibody assay. Western blot analysis detected antibodies in only eight of the serum samples, whereas an enzyme-linked immunosorbent assay (ELISA) and immunoprecipitation assay using nondisrupted HPV 1 virions showed positive antibody reactivities for 71 and 64 individuals, respectively. We suggest from these results that the humoral response to L1 is mainly directed against native conformational epitopes present on the whole HPV 1 particle and that type-common epitopes are not largely involved. This was further demonstrated by the fact that when samples were tested in the same ELISA system using disrupted HPV 1 virions as the antigen instead of whole virus particles, the number of positive sera was reduced to 9 out of 83. We further conclude that humoral assays using antigenic material pertaining to disrupted HPV epitopes are of limited use, at least in the case of HPV type 1. There were no obvious correlations between the antibody assay results and clinical histories of wart infection except that a lower number of positive serum reactivities were found among the group of individuals claiming to have no past history of HPV infection.

A synthetic peptide defines a serologic IgA response to a human papillomavirus-encoded nuclear antigen expressed in virus-carrying cervical neoplasia

The growing awareness of the role of human papillomavirus (HPV) in cervical carcinoma has triggered a search for uncomplicated detection methods. To define a serologic response to HPV, we synthesized peptides based on sequences deduced from the genome of HPV type 16, the most common malignancy-associated type of HPV. One of these peptides reacted with IgA antibodies present in sera from 24 of 33 patients with cervical intraepithelial neoplasia or cervical carcinoma, whereas this peptide reacted with only 6 of 27 sera from individuals without cervical intraepithelial neoplasia. Immunoaffinity-purified human antipeptide IgA antibodies detected HPV-specific 58- and 48-kDa proteins in cervical carcinoma cell extracts and also detected a nuclear antigen in HPV-carrying cervical cancer cell lines and cervical intraepithelial neoplasia biopsied tissue. These antigens were also detected with mouse monoclonal and rabbit polyclonal antibodies to the same peptide. The results indicate that screening for infection with malignancy-associated types of HPV may be possible by simple synthetic peptide-based serology.

Detection of human papillomavirus deoxyribonucleic acid in the female genital tract

A total of 336 biopsies, scrapes and exfoliated cells from the cervix and from the lower genital tract were screened for human papilloma (HP) viral sequences of types 6, 11, 16 and 18 by Southern blot, dot blot and filter in situ (FISH) hybridizations with cloned 32P-radiolabeled HPV DNA probes. The specimens included cervical intraepithelial neoplasias (CIN I-III), carcinoma in situ and invasive carcinoma of the cervix and vagina, adenocarcinomas, vulvar and vaginal condylomata acuminata and healthy epithelial samples. The oncogenic HPV 16 was found in 46% of the cervical carcinomas. Most of the type 16 occurrences (75%) represented the third stage of inoperable cases. Similarly, HPV 18 was also most frequently present in this stage as well as in carcinoma in situ and in CIN III (25%, 18%). At the same time, in condylomata acuminata, types 6 and 11 were detectable in 88.7% of cares. In all, 13.5% of the normal samples harboured HPV DNA.