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

Specificity of L1 peptides versus virus-like particles for detection of human papillomavirus-positive cervical lesions in females attending Engativa Hospital, Bogota, Colombia

A serological test for the detection of human papillomavirus (HPV) infection in females at risk of developing cervical cancer could be based on conserved L1 peptides with low levels of antigenicity specifically recognized by antibodies from patients with cervical lesions infected with high-risk HPV (HR-HPV) types. The aim was to assess the ability of L1 peptides 18283, 18294, and 18301 compared with the ability of virus-like particles (VLPs) to identify these infections in females. A total of 391 HPV-infected female volunteers were interviewed, and peripheral blood and cervical cells were obtained for detection of anti-HPV antibodies and HPV DNA; all of the patients had a Pap smear test; 287 patients were referred for colposcopy or biopsy, according to gynecological criteria. The level of agreement, as determined by the use of the Lin coefficient (rho value), showed that 75 to 83% of females with HR-HPV DNA-positive cervical lesions had antibodies that recognized VLPs and peptide 18283, 18294, or 18301, while 15 to 23% of the HPV DNA-negative females with a normal cytology had antibodies that recognized these three peptides and 45% had antibodies that recognized VLPs. The rate of agreement between peptides and VLPs for antibody detection was higher for patients with HPV DNA-positive cervical lesions. Peptides 18283, 18294, and 18301 showed similar sensitivities for the detection of HR-HPV DNA-positive cervical lesions and were more specific than VLPs. Peptide 18301 might be detecting protective antibodies in HPV DNA-negative females with atypical squamous cells of undetermined significance. These peptides could be useful for the design of a serology test for the detection of HR-HPV infection in females with cervical lesions and at risk of cervical cancer.

A non-variable L1-peptide displays high sensitivity and specificity for detecting women having human papillomavirus-associated cervical lesions

Anti-human papillomavirus (HPV) antibody detection is promising technique for detecting women at risk of suffering cervical cancer, since potentially oncogenic, persistent, long-term HPV-infections elicit an antibody response which is rarely detected in transitory HPV-infection patients. We have identified a non-variable C-terminus L1-peptide, belonging to an alpha-helix surface exposed on L1-protein, specifically recognized by antibodies from HPV-associated cervical lesion patients. This peptide tested against 313 sera presented higher reactivity with antibodies from cervical cancer (OD mean 0.43+/-0.13) or cervical lesion patients (OD mean 0.41+/-0.17) than antibodies from normal cytology patients (OD mean 0.17+/-0.03). High-risk HPV-infected patients presented higher antibody reactivity (OD mean 0.36+/-0.17) than high-risk HPV-non-infected patients (OD mean 0.22+/-0.11). This peptide showed 88.36% sensitivity, 99.39% specificity and 94.21% correct classification of high risk-HPV cervical lesion or cervical cancer patients. This peptide should be taken into account for designing serological screening or diagnostic tests for use in a clinical scenario.

Two L1-peptides are excellent tools for serological detection of HPV-associated cervical carcinoma lesions

A persistent high risk human papillomavirus (HR-HPV) infection causes cervical intraepithelial lesions and cervical carcinoma. There is evidence that detecting anti-L1 antibodies could be successfully used for discriminating between cervical lesion patients and women having normal cytology. It was found that peptides 18283 (55PNNNKILVPKVSGLQYRVFR74) and 18294 (284LYIKGSGSTANLASSNYFPT300) from the L1-surface exposed regions were specifically recognised by antibodies from the cervical lesion patient sera. These peptides were tested against 165 womens' normal cytology sera and 148 cervical lesion or cervical cancer patients' sera. Less than 3.6% of women's normal cytology sera recognised peptides 18283 or 18294; on the contrary, 91% to 96% of the cervical lesion (CIN I to CIN III) or cervical cancer patient sera recognised peptides 18283 and 18294. These data show that anti-peptide 18283 and 18294 antibodies in the patients' sera are strongly associated with the presence of HR-HPV associated cervical lesions, showing 92-97% sensitivity and 89-95% specificity in recognising precancerous and cervical cancer patients. These two peptides could be excellent tools for use in large-scale serological screening of women populations at risk of developing cervical carcinoma.

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.

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.

Serum oestradiol in women with carcinomas of the breast and uterine cervix

Endogenous oestrogens are thought to be involved in breast cancer, but few studies could show the direct relationship between hormones and pathological process of the disease. In the present study, oestradiol was estimated in the serum of pre-and postmenopausal breast cancer patients along with normal healthy controls and patients with carcinoma of the uterine cervix which is not dependent on oestrogens. Premenopausal patients with breast cancer showed higher levels of oestradiol as compared to premenopausal control women as well as cervical cancer patients. Whereas, no statistically significant differences were observed in serum oestradiol levels amongst postmenopausal groups of breast cancer, cervical cancer and normal women. The result of the study reflects the association of oestradiol as well as its difference in the pathological events of pre and postmenopausal breast cancer.

Diagnostic phase antibody response to the human papillomavirus type 16 E2 protein is associated with successful treatment of genital HPV lesions with systemic interferon alpha-2b

BACKGROUND AND OBJECTIVE

Systemic interferon alpha-2b treatment reduces relapses of genital human papillomavirus (HPV) lesions in some but not all females. The aim of the present study was to investigate possible predictive pretreatment factors for the outcome of therapy.

MATERIAL AND METHODS

HPV DNA status and HPV antibody response were evaluated in 100 randomized patients treated with laser ablation and systemic interferon alpha-2b or placebo, and followed up to 6 months.

RESULTS

Overall, adjuvant therapy with systemic interferon-alpha did not differ from placebo. However, detectable diagnostic phase levels of serum antibodies to e.g. HPV16 open reading frame (ORF) E2 derived peptide 141EEASVTVVEGQVDYY155 predicted 10-fold difference in the risk of recurrence of HPV infection following adjuvant interferon alpha-2b therapy as compared with placebo (odds ratio, OR, 0.5, 95% confidence interval (CI), 0.1-2.3; OR, 4.6, 95% CI 0.5-41, respectively). This trend was statistically significant in the whole study population (2P < 0.05), and in patients with high viral load (2P < 0.01).

CONCLUSIONS

Evaluation of the E2 antibody responses may help to identify women with genital HPV lesions who respond to systemic interferon alpha-2b treatment.