Human papillomavirus 16 (HPV 16) and HPV 18 antibody responses measured by pseudovirus neutralization and competitive Luminex assays in a two- versus three-dose HPV vaccine trial

Human papillomavirus 16 (HPV 16) and HPV 18 antibody responses in a 2- versus 3-dose HPV vaccine (Gardasil) trial were measured by a pseudovirus neutralizing antibody (PsV NAb) assay and by the Merck competitive Luminex immunoassay (cLIA). Eight hundred twenty-four female subjects assigned to three dosing regimens (group 1, 9 to 13 years old; 2 doses, months 0 and 6 [n = 259]; group 2, 9 to 13 years old; 3 doses, months 0, 2, and 6 [n = 260]; group 3, 16 to 26 years old; 3 doses, months 0, 2, and 6 [n = 305]) had postvaccine responses assessed 1 month after the last dose. Of 791 subjects with baseline and 7-month sera, 15 (1.9%) and 9 (1.1%) were baseline seropositive for HPV 16 and HPV 18, respectively. All baseline-seronegative vaccinees seroconverted to both HPV 16 and HPV 18. Mean anti-HPV 16 levels were similar for groups 1 and 2 (for PsV NAb, P = 0.675; for cLIA, P = 0.874), and levels for both groups 1 and 2 were approximately 2-fold higher than that for group 3 (for PsV NAb and cLIA, P < 0.001). Mean anti-HPV 18 levels were approximately 1.4-fold lower in group 1 than in group 2 (for PsV, NAb P = 0.013; for cLIA, P = 0.001), and levels for both groups 1 and 2 were approximately 2.0- to 2.5-fold higher than that for group 3 (for PsV NAb and cLIA, P < 0.001). Pearson correlation coefficients for the assays were 0.672 for HPV 16 and 0.905 for HPV 18. Most of the discordant results were observed at lower cLIA signals. These results suggest that the PsV NAb assay could be a suitable alternative to cLIA for the measurement of postvaccine antibody responses.     

Immunogenicity of the Quadrivalent Human Papillomavirus (Type 6/11/16/18) Vaccine in Males 16 to 26 Years Old

Human papillomavirus (HPV) infection can lead to significant disease in males, including anogenital warts, intraepithelial neoplasias, and several types of oral and anogenital cancers. The quadrivalent HPV (type 6/11/16/18) L1 virus-like particle (VLP) vaccine (qHPV vaccine; Gardasil) has recently been demonstrated to prevent persistent infection and associated disease related to vaccine HPV types in males. We report the overall immunogenicity results from a trial of the quadrivalent HPV vaccine in males. Overall, 3,463 heterosexual men and 602 men who had sex with men were enrolled into a randomized, placebo-controlled, double-blind safety, immunogenicity, and efficacy study. Serum samples were collected prior to vaccination at day 1 and at months 7, 24, and 36 postvaccination. Immunogenicity was evaluated with a multiplex, competitive Luminex immunoassay. Almost all subjects (97.4 to 99.2%) seroconverted for vaccine HPV types by month 7. At month 36, 88.9%, 94.0%, 97.9%, and 57.0% of subjects were still seropositive for HPV-6, -11, -16, and -18, respectively. For all vaccine HPV types, black subjects had significantly higher antibody titers at month 7 than did both Caucasian and Asian subjects. An anamnestic antibody response was seen in men seropositive before vaccination. The vaccine was highly immunogenic in males 16 to 23 years of age; responses were comparable to those observed in women. Furthermore, the immune responses were consistent with the established efficacy of the vaccine in the prevention of incident and persistent HPV infection, anogenital warts, and anal intraepithelial neoplasia.     

Comparison of Different Assays To Assess Human Papillomavirus (HPV) Type 16- and 18-Specific Antibodies after HPV Infection and Vaccination

We compared the measurement of human papillomavirus (HPV)-specific serum antibody levels with the virus-like-particle multiplex immunoassay (VLP-MIA), competitive Luminex immunoassay (cLIA), and glutathione S-transferase (GST) L1-based MIA. Using a large panel of serum samples, these assays showed mutually good correlations for both naturally induced and vaccine-derived HPV-specific antibody levels. However, an adaptation of the GST L1-based MIA resulted in an improved correlation with both cLIA and VLP-MIA.     

Mother-Infant Transfer of Anti-Human Papillomavirus (HPV) Antibodies following Vaccination with the Quadrivalent HPV (Type 6/11/16/18) Virus-Like Particle Vaccine

The exploratory immunogenicity objective of this analysis was to characterize the titer of vaccine human papillomavirus (HPV)-type immunoglobulins in both peripartum maternal blood and the cord blood of infants born to women who received blinded therapy. Data were derived from a randomized, placebo-controlled, double-blind safety, immunogenicity, and efficacy study (protocol 019; {"type":"clinical-trial","attrs":{"text":"NCT00090220","term_id":"NCT00090220"}}NCT00090220). This study enrolled 3,819 women between the ages of 24 and 45 years from 38 international study sites between 18 June 2004 and 30 April 2005. Data in the current analysis are from subjects enrolled in Philippines and Thailand. For each of HPV types 6, 11, 16, and 18, maternal anti-HPV was found in cord blood samples. Furthermore, HPV titers in cord blood samples were highly positively correlated with maternal HPV titers. Additionally, there were instances when anti-HPV antibodies were no longer detectable in maternal serum samples and yet were detected in matched cord blood samples. These results demonstrate that quadrivalent HPV (qHPV) vaccine-induced antibodies cross the placenta and could potentially provide some benefit against vaccine-type HPV infection and related diseases such as recurrent respiratory papillomatosis.     

Evaluation of the HPV 18 antibody response in Gardasil® vaccinees after 48 mo using a pseudovirion neutralization assay

The pseudo-neutralization assay (PsV) described in the current report allows for the creation of HPV18 pseudovirions in order to evaluate whether the antibody responses elicited following vaccination with Gardasil(?) are sufficient to neutralize the activity of these pseudovirions in vitro. The PsV assay evaluates a broader antibody response than the HPV competitive Lumniex Immunoassay (cLIA), which monitors the presence of a single neutralizing epitope. We employed two different approaches to the HPV18-PsV assay: one using standard dilutions of heat inactivated serum from vaccinated subjects, as is typically reported in the literature, and the other using heat inactivated serum from which IgG antibodies were purified and quantitated as an attempt to reduce assay background and achieve a level of quantitation greater than that afforded through simple dilution. Here, we show that after 48 mo, Gardasil(?) vaccinated subjects from three groups defined by HPV 18 cLIA titer have detectable HPV18 neutralizing antibodies as measured by either approach in the HPV18-PsV assay. These data support the observed sustained HPV18 protection against persistent infection and disease with the absence of breakthrough cases in Gardasil(?) vaccinees and suggests that neutralizing antibodies are present although they may no longer be detectable by cLIA.     

Seroprevalence of HPV vaccine types 6, 11, 16 and 18 in HIV-infected women from South Africa, Brazil and Botswana

Background

Many resource limited settings (RLS) suffer from high rates of both cervical cancer and HIV. Limited HPV serology data are available from RLS; such data could help describe local patterns of HPV infection and predict vaccine efficacy.

Objectives

To determine seropositivity to HPV types 6, 11, 16 and 18 in HIV-infected women from South Africa (SA), Botswana and Brazil.

Study design

HPV serotyping for high-risk types 6, 11, 16 and 18 was performed on samples collected from HIV-infected women from 2003–2010 using competitive Luminex Immuno Assay (HPV-4cLIA). We examined the association between seropositivity to these HPV types and country of enrollment, CD4, HIV-1 RNA level, and Pap smear.

Results

HPV serology results were available for 487 HIV-infected women (157, 170 and 160 from SA, Botswana and Brazil respectively). Approximately 65% of women had serum antibodies to one of the 4 HPV types and less than 3% of women had antibodies all 4 serotypes. Approximately 30% women demonstrated antibodies to type 16 HPV. Rates of seropositivity to HPV 11, and HPV 16+18 varied significantly between countries. Statistical difference was also shown in women in different age categories in the different countries. There was no difference in serology results compared by CD4 count, HIV viral load or Pap smear results.

Conclusions

These data suggest that the quadrivalent vaccine may be effective in preventing HPV infection in these countries.     

Reactivity of human sera in a sensitive, high-throughput pseudovirus-based papillomavirus neutralization assay for HPV16 and HPV18

Sensitive high-throughput neutralization assays, based upon pseudoviruses carrying a secreted alkaline phosphatase (SEAP) reporter gene, were developed and validated for human papillomavirus (HPV)16, HPV18, and bovine papillomavirus 1 (BPV1). SEAP pseudoviruses were produced by transient transfection of codon-modified papillomavirus structural genes into an SV40 T antigen expressing line derived from 293 cells, yielding sufficient pseudovirus from one flask for thousands of titrations. In a 96-well plate format, in this initial characterization, the assay was reproducible and appears to be as sensitive as, but more specific than, a standard papillomavirus-like particle (VLP)-based enzyme-linked immunosorbent assay (ELISA). The neutralization assay detected type-specific HPV16 or HPV18 neutralizing antibodies (titers of 160-10240) in sera of the majority of a group of women infected with the corresponding HPV type, but not in virgin women. Sera from HPV16 VLP vaccinees had high anti-HPV16 neutralizing titers (mean: 45000; range: 5120-163840), but no anti-HPV18 neutralizing activity. The SEAP pseudovirus-based neutralization assay should be a practical method for quantifying potentially protective antibody responses in HPV natural history and prophylactic vaccine studies.     

Antibody response for L1, E6 and E7 HPV 16 and HPV 18 antigens in Tunisian women with cervical cancer and controls

Results obtained in the present work indicated that the Luminex assay is more sensitive than ELISA. The reactivity to the early antigens E6 and E7 was 37% versus 42% for HPV 16 and 21% versus 20% for HPV 18 among cervical cancer cases using ELISA. However, these ratios were 44% and 61%, respectively, for E6 and E7 HPV 16 versus 28% and 21% for E6 and E7 HPV 18 when using the Luminex technique. Data also indicated that HPV 16 and HPV 18 showed distinct profiles for the different antigens tested. Finally, the differences in antibody responses between cervical cancer cases and benign cases toward the different antigens were significant.     

Human papillomavirus type 11 neutralization in the athymic mouse xenograft system: Correlation with virus-like particle IgG concentration

Neutralization of virus is likely to be necessary for development of an effective prophylactic vaccine against genital human papillomavirus (HPV) infection. Two New Zealand white rabbits were immunized with purified HPV type 11 (HPV 11) virions in Freund's adjuvant. An enzyme linked immunoassay (ELISA) was used to determine the quantity of IgG which recognized the HPV 11 major capsid protein (L1 protein) virus-like particles (VLPs) in the two anti-HPV 11 sera (serum A and serum B). The concentration of HPV 11 L1 VLP-specific IgG in the A and B sera were determined to be 37 and 90 μg per ml, respectively. The A and B sera were used in neutralization experiments in the athymic mouse xenograft system with known quantities of purified HPV 11 virions. The concentration of HPV 11 L1 VLP-specific IgG required to neutralize HPV 11 was determined for each antiserum. This concentration of IgG was approximately 700 to 900 ng per ml. This study demonstrates a positive correlation between the level of HPV 11 L1 VLP-specific IgG in animals immunized with HPV 11 virions and neutralization of HPV 11 in the athymic mouse model. Further studies are needed 1) to determine if sera or genital secretions from other species are neutralizing in the athymic mouse xenograft system, and 2) to determine if the VLP ELISA can be used as a reliable substitute for more cumbersome neutralization assays. J. Med. Virol. 53:185–188, 1997. © 1997 Wiley-Liss, Inc.     

Polymer-based enzyme-linked immunosorbent assay using human papillomavirus type 16 (HPV16) virus-like particles detects HPV16 clade-specific serologic responses

Human papillomavirus type 16 (HPV16) virus-like particles (VLP) were used as antigen in a polymer enzyme-linked immunosorbent assay (ELISA) to measure antibodies to HPV capsid proteins. Serum samples from 575 college women, previously tested for the presence of cervicovaginal HPV DNA, were analyzed. The prevalences of anti-HPV16 VLP antibodies at baseline were 14.1% for immunoglobulin G (IgG) and 6.4% for IgA. The seroprevalences of IgG in women with cervicovaginal HPV16, HPV16-related types, and other HPV types were 55, 33, and 19%, respectively (P < 0.001), compared to the prevalence in women without an HPV infection (10%). HPV VLP IgA seropositivity was associated with high HPV16 VLP IgG optical density values. The seropositivity of IgG antibodies was independently associated with infection with HPV16 or HPV16-related types, increased number of lifetime male partners for vaginal sex, having sex with men >/= 5 years older, history of abnormal PAP smear, older age, and living separately from parents. Use of HPV16 VLP polymer ELISA detects clade-specific responses and suggests an HPV16 VLP vaccine may have broader protection that initially anticipated.     

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

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

Measles seroprevalence in pregnant women in Soweto,South Africa: a nested cohort study

ObjectivesMeasles infection causes particularly severe disease in young children who, prior to vaccination, are dependent on maternal antibodies for protection against infection. Measles vaccination was introduced into the South African public immunization programme in 1983 and became widely available in 1992. The aim of this study was to determine measles-specific immunoglobulin G (IgG) levels in pregnant women living with and without HIV born before and after measles vaccine introduction in South Africa.MethodsMeasles IgG antibody level from blood obtained at the time of delivery was compared between women who were born before 1983 (n = 349) and since 1992 (n = 349). Serum samples were tested for measles IgG antibody using an enzyme-linked immunosorbent assay. Geometric mean titres (GMTs) and the proportion with seronegative (<200 mIU/mL) or seropositive titres (≥275 mIU/mL) were compared.ResultsWomen born since 1992 had lower GMTs [379.7 mIU/mL (95% CI 352.7–448.6)] and fewer were seropositive (55.9%, 195/349) than women born before 1983 [905.8 mIU/mL (95% CI 784.7–1045.5); 76.8%, 268/349], for both comparisons p < 0.001.ConclusionsWe found an association between measles vaccine implementation into the public immunization program in South Africa and peri-partum maternal measles immunity, where women born before vaccine introduction had higher measles IgG antibody titres and were more likely to be seropositive. These findings suggest a need to reconsider the infant measles immunization schedule in settings where women have derived immunity mainly from measles vaccine rather than wild-type virus exposure.     

Comparison of oral fluid and serum ELISAs in the determination of IgG response to natural human papillomavirus infection in university women.

BACKGROUND: Venipuncture (phlebotomy) is an obstacle to subject recruitment and ongoing participation in cohort studies investigating human papillomavirus (HPV) infection. Anti-HPV antibodies are not only detected in serum but also in oral fluid. OBJECTIVES: To evaluate if oral fluid specimens can be used in lieu of blood specimens for determining HPV antibody status. STUDY DESIGN: One hundred and seven paired oral fluid and blood specimens from female university students were tested in a HPV16 ELISA and compared to sexual history and serial genital HPV16 DNA status. RESULTS: ELISA results were in agreement in 97% (104/107) of paired sera and oral fluid. Of six women with positive anti-HPV16 serum samples, only three had positive oral fluid specimens. However, the specificity of the oral fluid test was 100% compared to the blood test. CONCLUSIONS: Detection of antibodies in oral fluid correlated with antibodies but was less sensitive than sera. A larger validation study is required to fully characterize the oral fluid assay.     

Flexibility in the administration schedule of varicella vaccination in healthy adolescents and young adults

A clinical trial to assess the immunogenicity and reactogenicity of two doses of varicella vaccine (live attenuated Oka-strain, GlaxoSmithKline Biologicals), when either given 8 or 4 weeks apart in healthy seronegative adolescents and young adults, was conducted in Khon Kaen and Bangkok, Thailand. Contrary to seroconversion rates generally reported for this age group, in our study all subjects were already seropositive after the first vaccine dose. After the first vaccine dose, geometric mean titers (GMTs) for anti-varicella antibodies were 78.4 (median 64) for the adolescent group and 136.5 (median 128) for the young adult group. Six weeks after administration of the second dose, anti-varicella GMTs reached 331.7 (median 256) and 636.9 (median 512) for the adolescent and young adult groups, respectively, with a 4.2-4.7-fold increase from pre-vaccination titers. The difference in GMTs between post-dose I and dose II was statistically significant for each group. The reactogenicity after the first and second doses of vaccination was low: no varicella rash was seen, in either the shorter or longer schedule. GlaxoSmithKline Biologicals varicella vaccine (Varilix) offered a high flexibility, administration possible at either 4 or 8 weeks interval, whilst eliciting good immunogenicity and good tolerability.     

Simultaneous quantitation of antibodies to neutralizing epitopes on virus-like particles for human papillomavirus types 6, 11, 16, and 18 by a multiplexed luminex assay

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

The seroprevalence of IgG antibodies to human papillomavirus (HPV) types HPV-16, HPV-18, and HPV-11 capsid-antigens in mothers and their children

Human papillomavirus (HPV) types causing anogenital lesions and cancer are accepted as being sexually transmitted. The methods whereby children acquire these anogenital type HPV infections are unclear. The present study determined the prevalence of anti-HPV-16, HPV-11 and HPV-18 IgG antibodies in mothers and their children in an attempt to identify evidence of HPV transmission from mother to child. HPV virus-like particles (VLP) VLP-16, VLP-11 and VLP-18 were used in enzyme-linked immunosorbent assay to identify IgG antibodies in serum from 100 mothers and their 111 children. Antibodies to VLP-16, VLP-11 and VLP-18 were found in serum from 17%, 21% and 16% of mothers, respectively and seroprevalences were 9%, 11.7% and 9.9%, respectively amongst the children. Of the 111 children, 23 (20.7%) showed antibodies to one or more of the three HPV types tested. Seven of these (30.4%) HPV IgG positive children had the same antibodies to one or more HPV types as their mothers. The prevalence of HPV-11 was similar in children of seropositive compared with seronegative mothers (14% and 11%, respectively). The prevalence of HPV-16 and HPV-18 was higher in children of seropositive mothers compared with seronegative mothers (for HPV-16, 18% and 7%, respectively, P = 0.1, for HPV-18, 19% and 8%, respectively, P = 0.2). None of these differences were statistically significant indicating a lack of correlation between antibodies in mothers and children and no evidence to support vertical or horizontal mother to child transmission of HPV infection. Indications were of multiple sources of HPV infection in the children.     

Sustained immunogenicity and efficacy of the HPV-16/18 AS04-adjuvanted vaccine: up to 8.4 years of follow-up

Prophylactic human papillomavirus (HPV) vaccines are now available and vaccination programs are being widely implemented, targeting adolescent girls prior to sexual debut. Since the risk of HPV exposure persists throughout a woman's sexual life, the duration of protection provided by vaccination is critical to the overall vaccine effectiveness. We report the long-term efficacy and immunogenicity of the HPV-16/18 AS04-adjuvanted vaccine (Cervarix (?) ) up to 8.4 y after the first vaccine dose. In an initial placebo-controlled study performed in US, Canada and Brazil, women aged 15-25 y with normal cervical cytology, HPV-16/18 seronegative by ELISA, DNA-negative for 14 oncogenic HPV types by PCR, received either the HPV-16/18 vaccine or placebo (n = 1,113). Subjects were followed up to 6.4 y after the first dose (n = 776). We report an additional 2-y follow-up for women enrolled from the Brazilian centers from the initial study (n = 436). During the current follow-up study (HPV-023, NCT00518336), no new infection or lesions associated with HPV-16/18 occurred in the vaccine group. Vaccine efficacy over the entire follow-up (up to 8.4 y) was 95.1% (84.6, 99.0) for incident infection, 100% (79.8, 100) for 6-mo persistent infection, 100% (56.1, 100) for 12-mo persistent infection and 100% (< 0, 100) for CIN2+ associated with HPV-16/18. All women in the vaccine group remained seropositive to both HPV-16/18, with antibody titers for total and neutralizing antibodies remaining several-folds above natural infection levels. The safety profile was clinically acceptable for both vaccine and control groups. This is, to date, the longest follow-up study for a licensed cervical cancer vaccine.     

Seroresponses to virus-like particles of human papillomavirus types 16, 18, 31, 33, and 45 in San people of Southern Africa

Virus-like particles (VLPs) of the high-risk human papillomavirus (HPV) types 16, 18, 31, 33, and 45 were used as antigen in enzyme-linked immunosorbent assay (ELISA) to determine the prevalence of serum IgG in a group of San people originally from Namibia, now residing in South Africa. The San children had low seroprevalence to all VLP types, but 26/115 (22.6%) of the children were seropositive to at least 1 VLP type. Among the adults, seroprevalence was significantly higher. The seroprevalence of antibodies in 101 San women to VLP-16 was 16.8%, VLP-18 18.8%, VLP-31 12.9%, VLP-33 17.8%, and VLP-45 22.8%. Five of the 11 men were seropositive: 2 for VLP-31, 1 for VLP-18, 1 for VLP-33, and 1 for VLP-45. Seroreactivity appeared to be type specific, except possibly to VLP-18 and -45. Of the adults, 50.5% were seropositive to at least 1 VLP type and 24.8% were seropositive to >1 VLP type. From this study, it is concluded that the San people are exposed to HPV-16, -18, -31, -33, and -45, with antibodies to VLP-45 being the most prevalent.     

Modified HPV16 E7 Genes as DNA Vaccine against E7-Containing Oncogenic Cells

Therapeutic vaccines against tumors associated with human papillomaviruses (HPV) should elicit cellular immune responses against early HPV antigens, primarily the oncoproteins E7 and E6. Because of safety concerns, the direct use of an unmodified oncogene is impossible in human DNA vaccination. Therefore, we introduced three point mutations into the pRb-binding site of HPV16 E7 oncogene to eliminate its transformation potential. The resultant gene was denoted E7GGG. The rates of expression and the cellular localization of E7 and E7GGG proteins were comparable. In immunization-challenge experiments, the efficacy of plasmids containing the E7, E7GGG, or fusion genes of HPV16 E7, viz. L1DeltaCE7(1-60) (M. Muller et al., 1997, Virology 234, 93-111), and Sig/E7/LAMP-1 (T. C. Wu et al., 1995, Proc. Natl. Acad. Sci. USA 92, 11671-11675), was compared. While tumors developed in all animals immunized with the wild-type E7 gene, a significant proportion of mice remained tumor-free after vaccination with the E7GGG gene. The fusion gene L1DeltaCE7(1-60) induced negligible protection, but Sig/E7/LAMP-1 conferred the highest protection. Intradermal immunization by gene gun proved superior to i.m. inoculation. In "therapeutic" experiments, a 1-day delay between inoculation of oncogenic cells and the start of DNA immunization resulted in partial therapeutic effect, but a 3-day delay produced a substantially lower immunization effect. A combination of Sig/E7/LAMP-1 and E7GGG genes did not enhance the immune response. These results demonstrate a significant enhancement of HPV16 E7 immunogenicity after mutagenesis of the pRb-binding site, but the mutated E7 gene did not excel the Sig/E7/LAMP-1 fusion gene.     

HIV‐1 seroconversion promotes rapid changes in cervical human papillomavirus (HPV) prevalence and HPV‐16 antibodies in female sex workers

The extent to which human immunodeficiency virus (HIV‐1) infection impacts on the ability to mount an effective immune response to HPV is unknown, but is relevant in planning HPV vaccine strategies for HIV‐1 infected individuals. This longitudinal study investigated changes shortly after HIV‐1 seroconversion on cervical HPV types and HPV‐16 antibody responses in serum and at the cervix of female sex workers. Typing of HPV DNA from cervical cells was done prior to HIV‐1 seroconversion and within 1 year and greater than 2 years after HIV‐1 seroconversion. Antibody determinations on serum and cervico‐vaginal rinse samples were by HPV‐16 virus‐like particle‐based, enzyme‐linked immunosorbent assay. Of 104 women tested, 40 (38.4%) became HIV‐1 seropositive (HIV‐positive) during the course of the study. Shortly after HIV‐1 seroconversion a significant increase in multiple (>1) HPV infection (OR 4.0, 95% CI 1.3–11.9) was observed compared with HIV‐1 seronegative (HIV‐negative) women and certain changes in HPV type infection. HIV‐1 seroconversion resulted in a reduced prevalence of serum HPV‐16 IgA and cervico‐vaginal IgA and IgG but an increased prevalence of serum HPV‐16 IgG. All HIV‐positive women had been exposed to HPV‐16 as all displayed serum HPV‐16 IgG. Serum HPV‐16 responses were maintained at a high magnitude in the presence of HPV‐16 infection irrespective of HIV infection, but decreased in the absence of HPV‐16 infection. In conclusion, HIV‐1 seroconversion in sex workers rapidly increased cervical HPV infection and caused a reduced ability to produce cervical HPV‐16 antibodies but a continued ability to generate serum IgG antibodies. J. Med. Virol. 81:203–210, 2009. © 2008 Wiley‐Liss, Inc.