Determinants of human papillomavirus 16 serological conversion and persistence in a population-based cohort of 10 000 women in Costa Rica.

Determinants of human papillomavirus (HPV)-16 serological conversion and persistence were assessed in a population-based cohort of 10 049 women in Guanacaste, Costa Rica. Serologic responses to HPV-16 were measured in 7986 women by VLP-based enzyme-linked immunosorbent assay at both study enrollment (1993/94) and at 5-7 years of follow-up. Seropositive women were defined as >/=5 standard deviations above the mean optical density obtained for studied virgins at enrollment (n=573). Seroconnversion (n=409), persistence (n=675), and clearance (n=541) were defined based on enrollment and follow-up serology measurements. Age-specific distributions revealed that HPV-16 seroconversion was highest among 18- to 24-year-old women, steadily declining with age; HPV-16 seropersistence was lowest in women 65+ years. In age-adjusted multivariate logistic regression models, a 10-fold risk increase for HPV-16 seroconversion was associated with HPV-16 DNA detection at enrollment and follow-up; two-fold risk of seroconversion to HPV-16 was associated with increased numbers of lifetime and recent sexual partners and smoking status. Determinants of HPV-16 seropersistence included a 1.5-fold risk increase associated with having one sexual partner during follow-up, former oral contraceptive use, and a 3-fold risk increase associated with HPV-16 DNA detection at both enrollment and follow-up. Higher HPV-16 viral load at enrollment was associated with seroconversion, and higher antibody titres at enrollment were associated with seropersistence.

Seroprevalence of human papillomavirus-16, -18, -31, and -45 in a population-based cohort of 10000 women in Costa Rica.

Human papillomavirus (HPV) seroprevalence and determinants of seropositivity were assessed in a 10049-woman population-based cohort in Guanacaste, Costa Rica. Serologic responses based on VLP-based ELISA were obtained from the plasma collected at study enrollment in 1993/1994 for HPV-16 (n=9949), HPV-18 (n=9928), HPV-31 (n=9932), and HPV-45 (n=3019). Seropositivity was defined as five standard deviations above the mean optical density obtained for studied virgins (n=573). HPV-16, -18, -31, and -45 seroprevalence was 15, 15, 16, and 11%, respectively. Of women DNA-positive for HPV-16, -18, -31, or -45, seropositivity was 45, 34, 51, and 28%, respectively. Peak HPV seroprevalence occurred a decade after DNA prevalence; lifetime number of sexual partners was the key determinant of seropositivity independent of DNA status and age. DNA- and sero-positive women showed the highest risk for concurrent CIN3/cancer, followed by DNA-positive, sero-negative women.

Serum antibodies to human papillomavirus 16 proteins in women from Brazil with invasive cervical carcinoma.

Serum samples from 194 cases and 217 controls participating in a case-control study of invasive cervical cancer in Brazil were examined for antibodies to human papillomavirus (HPV) 16 virus-like particles (VLPs) by ELISA. The prevalence of antibody in cases and controls was 47.4 versus 24.4% (P < 0.001). The prevalence was higher in women who had HPV-16 DNA in the genital tract (54.2%) than in those with other HPVs (36.8%) or no HPVs (44.8%), but the differences were not statistically significant. Among cases and controls, HPV-16 VLP antibodies were associated with a greater number of lifetime sexual partners (chi2 for trend, P < 0.001). Among controls, age was inversely associated with HPV-16 VLP seroreactivity (chi2 for trend, P = 0.019). The sera were previously tested for antibodies to HPV-16 E6 and E7 oncoproteins; there was no correlation between antibody titers to HPV-16 E6 or E7 and VLPs. The HPV-16 serological assays were compared as screening tests for invasive cervical cancer. The sensitivity and specificity estimates were 47.4 and 75.6% for HPV-16 VLP serology, 63.4 and 89.9% for either HPV-16 E6 or E7 serology, and 53.6 and 93.6% for high titers of either HPV-16 E6 or E7 or VLP antibodies. The utility of HPV-16 VLP ELISA as a screening test for invasive cervical cancer is limited by a high seroprevalence in women with probable prior exposure to HVP 16 but without disease.

Adeno-associated virus and development of cervical neoplasia

Evidence from several sources has suggested that adeno-associated virus (AAV) infection might protect against cervical cancer, in part, by interfering with human papillomavirus (HPV)-induced tumorigenesis. Detection of AAV type 2 (AAV-2) DNA in cervical tissues has been reported. However, there have been few in vivo studies of women with cervical HPV infection or neoplasia, and these have reported inconsistent results. Therefore, we used polymerase chain reaction (PCR) assays targeted to the AAV-2 rep and cap genes to test tissue specimens from women in an epidemiological study of cervical neoplasia in Jamaica. We tested 105 women with low-grade cervical intraepithelial neoplasia (CIN-1), 92 women with CIN-3/carcinoma in situ or invasive cancer (CIN-3/CA), and 94 normal subjects. PCR amplification of human beta-globin DNA was found in almost all cervical specimens, indicating that these materials were adequate for PCR testing. The prevalence of HPV DNA, determined by HPV L1 consensus primer PCR was, as expected, strongly associated with presence and grade of neoplasia. Each of the AAV PCR assays detected as few as 10 copies of the virus genome. However, none of the 291 cervical specimens from Jamaican subjects tested positive for AAV DNA. Negative AAV PCR results were also obtained in tests of cervical samples from 79 university students in the United States. Exposure to AAV was assessed further by serology. Using a whole virus AAV-2 sandwich enzyme-linked immunosorbent assay, we found no relationship between AAV antibodies and presence or grade of neoplasia in either the Jamaican study subjects or women enrolled in a U.S. cervical cancer case (n = 74) - control (n = 77) study. Overall, the data provide no evidence that AAV infection plays a role in cervical tumorigenesis or that AAV commonly infects cervical epithelial cells.(Au)

Adeno-associated virus and development of cervical neoplasia.

Evidence from several sources has suggested that adeno-associated virus (AAV) infection might protect against cervical cancer, in part, by interfering with human papillomavirus (HPV)-induced tumorigenesis. Detection of AAV type 2 (AAV-2) DNA in cervical tissues has been reported. However, there have been few in vivo studies of women with cervical HPV infection or neoplasia, and these have reported inconsistent results. Therefore, we used polymerase chain reaction (PCR) assays targeted to the AAV-2 rep and cap genes to test tissue specimens from women in an epidemiological study of cervical neoplasia in Jamaica. We tested 105 women with low-grade cervical intraepithelial neoplasia (CIN-1), 92 women with CIN-3/carcinoma in situ or invasive cancer (CIN-3/CA), and 94 normal subjects. PCR amplification of human beta-globin DNA was found in almost all cervical specimens, indicating that these materials were adequate for PCR testing. The prevalence of HPV DNA, determined by HPV L1 consensus primer PCR was, as expected, strongly associated with presence and grade of neoplasia. Each of the AAV PCR assays detected as few as 10 copies of the virus genome. However, none of the 291 cervical specimens from Jamaican subjects tested positive for AAV DNA. Negative AAV PCR results were also obtained in tests of cervical samples from 79 university students in the United States. Exposure to AAV was assessed further by serology. Using a whole virus AAV-2 sandwich enzyme-linked immunosorbent assay, we found no relationship between AAV antibodies and presence or grade of neoplasia in either the Jamaican study subjects or women enrolled in a U.S. cervical cancer case (n = 74) -control (n = 77) study. Overall, the data provide no evidence that AAV infection plays a role in cervical tumorigenesis or that AAV commonly infects cervical epithelial cells.

A survey of human papillomavirus 16 antibodies in patients with epithelial cancers.

Human papillomavirus (HPV), particularly HPV 16, is linked to the development of cervical cancer. However, the role of HPV 16 in a number of extra-cervical epithelial tumours is controversial. To assess exposure to HPV 16 in patients with different cancers, we conducted a large serosurvey of 905 patients with 21 types of tumours and measured IgG to HPV 16 virus-like particles (VLPs) using a well characterized enzyme linked immunosorbent assay (ELISA). Patients with cervical cancer were considered 'positive controls', as about half were expected to be specifically HPV 16-related. A non-cancer study group consisting of 48 patients with endocrine disorders (eg diabetes) was also tested. HPV 16 antibody prevalence was highest in patients with cancers of the cervix (52% +/- 7%), vulva (27% +/- 9%), vagina (27% +/- 13%) and penis (63% +/- 16%). Seroprevalence was much lower in the non-cancer group (4% +/- 3%) and all other cancer patients: uterus (9% +/- 4%); ovary (4% +/- 3%); testis (5% +/- 4%); prostate (6% +/- 4%); squamous carcinoma (6% +/- 3%) and adenocarcinoma (4% +/- 3%) of the lung; rectum (2% +/- 2%); pancreas (8% +/- 4%); colon (2% +/- 2%); stomach (0%); oesophagus (8% +/- 4%); buccal cavity (12% +/- 5%); breast (10% +/- 4%); non-melanomatous (9% +/- 6%) and melanomatous (6% +/- 3%) skin tumours; bladder (8% +/- 4%); and kidney (2% +/- 2%). The results confirm the strong relation of HPV with several lower anogenital tract tumours, but, at least in this population, fail to identify additional epithelial tumours associated with high seroprevalence of HPV 16 VLP antibodies.

Antibody to human immunodeficiency virus type 1 (HIV-1) gp160 in mucosal specimens of asymptomatic HIV-1-infected volunteers parenterally immunized with an experimental recombinant HIV-1 IIIB gp160 vaccine. The National Institute of Allergy and Infectious Diseases-sponsored AIDS Vaccine Evaluation Group.

Twenty-two human immunodeficiency virus type 1 (HIV-1)-infected, asymptomatic volunteers with CD4 cell counts of >600 cells/mm3 who were enrolled in a phase I immunotherapy trial comparing two schedules of immunization of an HIV-1 IIIB-based recombinant gp160 (rgp160) experimental vaccine were evaluated for rgp160-specific antibodies in parotid saliva, genital secretions, and serum. When the study was unblinded, it was determined that five volunteers had received rgp160 on a month 0, 1, 2, 3, 4, and 5 immunization schedule, seven volunteers had received rgp160 on a month 0, 1, 2, and 5 schedule, five had received alum/deoxycholate placebo, and seven had received a licensed hepatitis B virus vaccine. Five volunteers consented to the donation of parotid saliva but not genital secretions. Prior to immunization, parotid saliva specimens were available for 11 of 22 volunteers, seminal plasma (SP) specimens were available for 7 of 22 volunteers, cervicovaginal lavage (CVL) specimens were available for 5 of 22 volunteers, and serum was available for 22 of 22 volunteers. These baseline specimens and specimens collected at 1 and 7 months after the final immunizations were assessed by enzyme-linked immunosorbent assay for immunoglobulin G (IgG) and IgA antibodies specific for HIV-1 LAI rgp160 or HIV-1 MN rgp160. No augmentation in HIV rgp160-specific IgG or IgA antibody production in either parotid saliva or serum specimens of vaccinees compared to that in controls was observed after immunization. There were insufficient numbers of SP or CVL specimens available for statistical comparisons between vaccinees and controls. Overall, anti-LAI rgp160 IgG antibodies were detected in the parotid saliva specimens of 20 of 22 volunteers, the seminal plasma specimens of 11 of 11 volunteers, and the CVL specimens of 6 of 6 volunteers and in 21 of 22 serum specimens. Fewer volunteers expressed anti-LAI rgp160 IgA antibodies in mucosal or serum specimens: 11 of 22 parotid saliva specimens, 3 of 11 SP specimens, 3 of 5 CVL samples, and 12 of 22 sera.

Prevalence of antibodies to human papillomavirus (HPV) type 16 virus-like particles in relation to cervical HPV infection among college women.

A human papillomavirus type 16 (HPV-16) virus-like particle (VLP)-based enzyme-linked immunosorbent assay (ELISA) was used to measure serum antibody to capsid proteins in 376 sexually active college women who were also screened for the presence of genital HPVs by PCR and interviewed for demographic and behavioral risk factors for HPV infection. The seroprevalence was 46% in women with HPV-16 DNA in the genital tract. The corresponding values for women who harbored other HPV types or no HPV in the genital tract were 30 and 19%, respectively (HPV-16 group versus no-HPV group; odds ratio [OR], 3.7; 95% confidence interval [CI], 1.5 to 8.9). The antibody response was significantly higher among women with a high viral load than among those with a low viral load (median optical density value, 0.838 versus 0.137, P = 0.009). Comparable levels of seroreactivity were observed among women infected with HPV types distantly or closely related genetically to HPV-16. Seroreactivity was significantly associated with an age of 25 to 30 years (OR, 2.3; 95% CI, 1.2 to 4.4), three or more lifetime sexual partners (OR, 2.9; 95% CI, 1.1 to 10), and history of a sexually transmitted disease other than HPV (OR, 3.1; 95% CI, 1.5 to 6.3). The percent seropositivity increased linearly with number of lifetime sexual partners until reaching a plateau at 35% for women with more than six partners (chi for linear trend, P < 0.001). The low sensitivity of HPV-16 VLP-based ELISA may limit the usefulness of the assay as a diagnostic test for HPV-16 infection. However, the assay appears to have adequate specificity and should be useful as an epidemiological marker of HPV-16 infection and sexual behavior.

Antibodies to recombinant gp160 in mucosal secretions and sera of persons infected with HIV-1 and seronegative vaccine recipients.

An enzyme immunoassay (EIA) was developed to detect secretory IgA (sIgA) antibodies to HIV-1 envelope glycoprotein, using a mouse monoclonal antibody and a highly purified, baculovirus-expressed recombinant gp160 (rgp160) as antigen. Detection of sIgA was enhanced by prior immunoprecipitation of IgG. IgG and sIgA rgp160 antibodies were measured in parotid saliva and nasal wash samples of 18 HIV-1-seropositive volunteers and 14 HIV-1-seronegative adult volunteers immunized 3 times with HIV-1 IIIB rgp160 vaccine at 1 of 4 dosage levels: 40 micrograms (N = 3), 80 micrograms (N = 3), 160 micrograms (N = 4), and 640 micrograms (N = 4). We detected rgp160-specific IgG antibody in the nasal wash samples of all HIV-1-seropositive volunteers and 4/8 vaccinees (50%) immunized with the two highest doses of rgp160 vaccine. All infected volunteers tested had rgp160-specific sIgA in their nasal wash samples. None of the vaccinees and very few of infected volunteer specimens had detectable antibody in the parotid saliva samples (5/8 had IgG and 1/8 had sIgA). We also detected IgG antibody to rgp160 in the sera of all infected volunteers and 13/14 vaccinees (93%). With this EIA, sIgA antibody can be measured in mucosal secretions of recipients of appropriate candidate HIV-1 vaccines.

Humoral immune responses to gag and env proteins from human immunodeficiency virus type 1 in hemophiliac patients.

Solid-phase enzyme immunoassays using recombinant gag and env proteins were developed to study humoral immune responses to HIV infection in a cohort of 105 hemophiliac patients. Thirteen patients with ARC or AIDS and 92 asymptomatic patients were studied. A cross-sectional study showed a wide range of antibody responses to gag and env proteins; however, the differences between the ARC/AIDS and asymptomatic patients were statistically significant for both antigens (P less than .0004). In a longitudinal study, antibody levels in sera from 11 asymptomatic patients with gag antibody log units less than or equal to 1.5 were compared to levels in sera from 10 ARC/AIDS patients and 8 asymptomatic patients with gag antibody greater than 1.5. These patient groups were followed for comparable periods of time (67.1-71.7 mo). The asymptomatic patients with low gag antibody and the ARC/AIDS patients showed a similar pattern of antibody response to gag protein overtime. In hemophiliac patients with HIV-1 infection a low titer of antibody to gag protein is not invariably associated with clinical deterioration and is not a useful serologic marker of impending progression to AIDS.

Characterization of serum antibody responses to recombinant HIV-1 gp160 vaccine by enzyme immunoassay. NIAID AIDS Vaccine Clinical Trials Network.

An enzyme immunoassay (EIA) was developed to measure serum antibody responses of healthy adult volunteers vaccinated with 40 or 80 micrograms of human immunodeficiency virus type 1 (HIV-1) recombinant gp160 (rgp160) vaccine at 0, 1, 6, and 18 months. This assay, which used purified rgp160 as antigen, was compared with the Biotech/Du Pont HIV-1 Western blot and the Abbott HIV-1 EIA. Of 33 volunteers who received three doses of rgp160 vaccine, seroresponses were detected in 91% by rgp160 EIA, 97% by Western blot, and 30% by HIV-1 EIA. The level of IgG rgp160 EIA antibody (mainly IgG1) peaked after the third immunization; 64% of 33 vaccinees still had detectable antibody by 12 months. The fourth immunization induced anamnestic IgG EIA antibody in 23 of 24 vaccinees, with titers ranging from 1:200 to 1:25,600. Neutralizing antibody was not detected in postvaccination sera by microtiter syncytium formation inhibition assay. Additional testing of sera by EIA indicated that the immune response to the vaccine was directed toward epitopes on both gp120 and gp41. Seroresponses to the immunodominant epitopes on gp41 were infrequent and none were detected to the neutralization epitope in the V3 region of gp120. This highly sensitive EIA is useful for characterizing HIV-1-specific antibody responses induced by an HIV-1 gp160 subunit vaccine.

Reflectivity measurements on hot reactive liquids using a FIR laser.

The experimental procedures and precautions required to measure liquid-alloy reflectivities with a cw far infrared (FIR) laser are described. The output of a carefully stabilized optically pumped FIR laser was channeled to a melted sample contained in a silica holder under a He atmosphere. By maintaining specular reflection and alloy homogeneity, reflectivities reproducible to +/-7% were routinely obtained.