Characterization of an HLA-C-restricted CTL response in chronic HIV infection.

HIV-specific CTL play an important role in the host control of HIV infection. HIV-nef may facilitate escape of HIV-infected cells from CTL recognition by selectively downregulating the expression of HLA-A and HLA-B molecules, while surface expression of HLA-C is unaffected. The HLA-C-restricted CTL responses have previously been largely ignored and poorly characterized. We examined the frequency, function, and phenotype of HLA-C-restricted CTL in ten antiretroviral therapy-naïve Caucasian and African individuals with chronic HIV-1 infection (for at least 8 years; CD4 cell counts in the range of 50-350) who carried the HLA-Cw04 allele. HLA-Cw04-restricted CTL that recognize a conserved epitope within HIV-1 envelope (aa 375-383 SF9) were analyzed using IFN-gamma ELISPOT assays and phenotypic analysis was carried out by flow cytometry. HLA-C-restricted CTL play an important role in the HIV-specific response, and can account for as much as 54% of the total response. HLA-C-restricted CTL are functionally and phenotypically identical to HLA-A- and HLA-B-restricted CTL. HLA-C-restricted CTL in chronic HIV infection are memory cells of an intermediate phenotype, characterized by high CD27 and low CD28 expression and lack of perforin production.

Relationship between markers of HIV-1 disease progression and serum beta-carotene concentrations in Kenyan women.

Observational studies have suggested that low serum beta-carotene concentrations may influence HIV-1 disease progression. However, randomized trials have not demonstrated beneficial effects of beta-carotene supplementation. To understand this discrepancy, we conducted a cross-sectional study among 400 HIV-1-seropositive women in Mombasa, Kenya, to correlate serum beta-carotene concentrations with several measures of HIV-1 disease severity. beta-Carotene concentrations were significantly associated with biologic markers of HIV-1 disease progression (CD4 count, HIV-1 plasma viral load, serum C-reactive protein [CRP] concentration, and serum albumin level). In multivariate analysis, beta-carotene concentrations below the median were associated with elevated CRP (>10 mg/l, adjusted odds ratio [aOR] 3.32, 95% confidence interval [CI] 1.99-5.53, P<0.001) and higher HIV-1 plasma viral load (for each log(10) copies/mL increase, aOR 1.38, 95% CI 1.01-1.88, P=0.04). In the context of negative findings from randomized trials of beta-carotene supplementation in HIV-1-seropositive individuals, these results suggest that low beta-carotene concentrations primarily reflect more active HIV-1 infection rather than a deficiency amenable to intervention.

Identification of a novel HLA B*57 restricted cytotoxic T-lymphocyte epitope within HIV-1 rev.

HLA-B5701 and its related allele B5703 have been shown to be strongly associated with slow HIV-1 disease progression. To elucidate the effect of these alleles fully on disease progression it is essential to identify key HIV-1 epitopes that are restricted by these alleles. Here we describe the identification of a novel HLA-B5701, B5703 restricted epitope within HIV-1 rev, which accounted for up to 25 and 40% of the total cytotoxic T-lymphocyte responses in two patients.

The effect of rapid HIV-1 testing on uptake of perinatal HIV-1 interventions: a randomized clinical trial.

OBJECTIVE: We examined whether HIV-1 testing using a rapid assay increases the proportion of pregnant women obtaining HIV-1 results and the uptake of perinatal HIV-1 interventions. METHODS: Pregnant women attending public health clinics in Nairobi were offered voluntary counselling and testing for HIV-1. Consenting women were randomly assigned to receive either rapid or conventional HIV-1 testing. Women randomly assigned to rapid testing were allowed to receive same-day results or to return later. The results for women randomly assigned to conventional enzyme-linked immunosorbent assay (ELISA) testing were available after 7 days. HIV-1-infected women were referred for antiretroviral prophylaxis to prevent mother-to-child transmission of HIV-1. RESULTS: Among 1282 women offered voluntary HIV-1 testing and counselling, 1249 accepted testing, of whom 627 were randomly assigned to rapid testing and 622 to conventional testing. The median duration between testing and obtaining results was 0 days for women who received rapid testing compared with 11 days for women who received conventional testing. The percentage receiving HIV-1 results was significantly higher among women who received rapid testing compared with conventional testing. Of 161 HIV-1-seropositive women, only 24 received antiretroviral prophylaxis. The uptake of perinatal HIV-1 interventions did not differ between HIV-1-seropositive women randomly assigned to rapid testing or conventional ELISA testing. CONCLUSION: Rapid HIV-1 testing significantly increased the proportion of women receiving HIV-1 results, which is important for sexual and perinatal HIV-1 prevention. The challenge remains to improve the uptake of perinatal HIV-1 interventions among HIV-1-seropositive women.

Vulnerability of women in an African setting: lessons for mother-to-child HIV transmission prevention programmes.

After discussing advantages and risks, only a third of the 290 HIV-infected women included in an intervention study to reduce mother-to-child transmission of HIV in Mombasa, Kenya, informed their partners of their results. Despite careful counselling, 10% subsequently experienced violence or disruption of their relationship. To increase the uptake of interventions to reduce perinatal HIV transmission safely, we recommend the involvement of partners in HIV testing. In addition, the counselling of women has to address methods and skills to deal with violence.

HIV-1 Env-specific cytotoxic T-lymphocyte responses in exposed, uninfected Kenyan sex workers: a prospective analysis.

The prospective significance of HIV-specific cytotoxic T lymphocyte (CTL) responses in highly exposed, persistently seronegative populations is unknown. In 1996-1997 we screened for CTL responses against HIV clade B Env in 39 recently enrolled Kenyan female sex workers, and followed these women prospectively. Annual HIV incidence was 5.8%. CTL were independently associated with age and recent HIV-1 exposure,but were not prospectively associated with protection in a multivariable model that included HIV-1 exposure and duration of sex work.

Impact of HIV infection on invasive cervical cancer in Kenyan women.

OBJECTIVES: To determine the association between invasive cervical cancer (ICC) and HIV infection in Kenyan women. STUDY DESIGN: Case-control, with ICC patients as cases, and women with uterine fibroids as controls. METHODS: Medical and socio-demographic data were collected from 367 ICC patients, and 226 women with fibroids. After informed consent, HIV testing was done. RESULTS: ICC patients were older than fibroid patients (48 versus 41 years; P < 0.001), with an HIV seroprevalence of 15% and 12% respectively (P > 0.05). However, cases younger than 35 years were 2.6-times more likely to be HIV positive than controls of similar age [35% versus 17%; odds ratio (OR), 2.6; P = 0.043]. ICC HIV-seropositive patients were, on average, 10 years younger than HIV-seronegative patients (40 versus 50 years; P < 0.001). Eighty per cent of HIV-seropositive and 77% of HIV-seronegative ICC patients were in FIGO stage IIb or above. However, the odds of having poorly differentiated tumours was three times higher for HIV-seropositive than for HIV-seronegative ICC patients (77% versus 52%; OR, 3.1; P = 0.038) after adjusting for histological cell type and clinical stage. Mean CD4 cell count was 833 x 10(6) cells/l in ICC and 1025 x 10(6) cells/l in fibroid patients (P = 0.001). CONCLUSION: Young women with ICC were more often HIV infected than women with fibroids of the same age groups. HIV infection was associated with poor histological differentiation of the tumours. These findings suggest an accelerated clinical progression of premalignant cervical lesions to ICC in HIV-infected women.

Recombination following superinfection by HIV-1.

BACKGROUND: There is increasing recognition of recombinant HIV-1 strains globally, but it has been unclear whether recombination results from superinfection during untreated, chronic infection. OBJECTIVE: To search for evidence of recombination and superinfection in Africa, where multiple HIV-1 subtypes facilitate identification of strains. METHODS: Serial blood samples from highly exposed, chronically infected women in Nairobi's Pumwani sex workers cohort were examined. Serial, complete HIV-1 RNA sequence analyses were performed for seven untreated long-term survivors. Sequences were subjected to computational analysis. RESULTS: One woman had evidence of both superinfection and recombination. Complete HIV-1 RNA sequences were first derived from plasma obtained in 1986, when the woman had been HIV seropositive for at least 21 months; this sequence was entirely subtype A. The sequences obtained from plasma in 1995 and 1997, however, were subtype A/C recombinants with a SimPlot demonstrating that the subtype A fragment in 1995 and 1997 was derived from the original 1986 A sequence. Heteroduplex tracking assays demonstrated that the subtype C sequences were not detectable as minor species in 1986. CONCLUSION: Intersubtype recombination took place between the original non-recombinant subtype A strain and the superinfecting subtype C strain in an untreated, chronically infected woman. This finding helps to explain the rising prevalence of recombinant HIV-1 worldwide. Recombination resulting from superinfection with diverse strains may pose problems for eliciting broad immune responses necessary for an effective vaccine.

Quantitative ex vivo analysis of functional virus-specific CD8 T lymphocytes in the blood and genital tract of HIV-infected women.

BACKGROUND: CD8 T lymphocytes are important in HIV-1 control and mediate virus-specific immunity in the blood and genital tract. The induction and monitoring of mucosal CD8 cell responses will be an important component of HIV-1 vaccine trials, but information regarding the frequency, phenotype and function of genital tract CD8 cell responses is lacking. METHODS: Simultaneous blood and cervical cytobrush samples were obtained from 16 HIV-1-infected Kenyan sex workers. Epitope-specific CD8 T lymphocyte frequencies in the blood and genital tract were analysed after short-term peptide incubation and intracellular cytokine staining for interferon-gamma (IFN gamma). RESULTS: Cervical sampling resulted in adequate cell numbers for analysis in 10/16 women. Background IFN gamma production was higher in CD3+/CD8+ lymphocytes from the genital tract than from blood (0.48% versus 0.1%; P < 0.01). Responses to staphylococcal enterotoxin B were detected in cervical CD8 lymphocytes from 10/10 women, at a similar frequency to blood (16.7% in cervix and 13.3% in blood; P = 0.4). HIV-1-specific responses were detected the cervix of 8/10 women, with a trend to higher response frequencies in the genital tract than blood (2.1% versus 0.8%; P = 0.09). Co-expression of integrin CD103 (alpha E beta 7), a mucosal marker, was used to confirm the mucosal origin of cervical responses. CONCLUSIONS: Cytobrush sampling and intracellular cytokine staining is well suited to the analysis of cervical CD8 cell responses. The frequency of functional virus-specific CD3+/CD8+ T cells is similar in the genital tract and blood of HIV-1-infected women. The role of genital tract CD8 cell responses in HIV-1 control warrants further investigation.

Correlates of human herpesvirus 8 seropositivity among heterosexual men in Kenya.

BACKGROUND: Several studies have suggested that sexual transmission of human herpesvirus 8 (HHV-8) occurs among homosexual men in developed countries. However, few studies have examined heterosexual HHV-8 transmission, especially among African populations in which HHV-8 is endemic. OBJECTIVES: To determine the seroprevalence and correlates of HHV-8 infection among heterosexual African men. DESIGN: Cross-sectional study. METHODS: Participants were 1061 men enrolled in a prospective cohort study of risk factors for HIV-1 acquisition among trucking company employees in Mombasa, Kenya. Stored frozen sera from the study baseline visit were tested for antibodies to HHV-8 by whole-virus lysate ELISA. RESULTS: HHV-8 seroprevalence was 43%. In multivariate logistic regression analysis, HHV-8 infection was independently associated with older age [for men aged 30-39 years: odds ratio (OR), 1.5; 95% confidence interval (CI), 1.1-2.0; for men aged > or = 40 years: OR, 1.7; 95% CI, 1.1-2.7, compared with men aged < 30 years], Christian religion (OR, 1.6; 95% CI, 1.2-2.1), being uncircumcised (OR, 1.5; 95% CI, 1.0-2.2), and ever having syphilis (OR, 2.2; 95% CI, 1.4-3.5). Ever having used condoms was associated with decreased likelihood of infection (OR, 0.7; 95% CI, 0.6-1.0). Seropositivity was not significantly related to other sexual behaviors characterized or to HIV-1 status. CONCLUSIONS: HHV-8 seropositivity is common in this population and increases with age, suggesting on-going transmission during adulthood. Infection was more common among men who were uncircumcised or who had ever had syphilis and was less common among those who had ever used condoms, suggesting that sexual factors may play a role in HHV-8 transmission. Prospective studies of HHV-8 acquisition in heterosexual African populations are needed to demonstrate whether safer sexual practices can reduce transmission.

HLA typing in a Kenyan cohort identifies novel class I alleles that restrict cytotoxic T-cell responses to local HIV-1 clades.

OBJECTIVES: To investigate HLA class I allele frequencies in a Kenyan commercial sex worker (CSW) cohort, and to examine HIV-1 specific cytotoxic T lymphocyte (CTL) responses directed against epitopes derived from locally prevalent clade A virus. METHODS: PCR-single strand polymorphism HLA class I typing. Sequencing of novel alleles and examination of their distribution in the CSW cohort, and a low risk HIV uninfected cohort. The peptide-binding motif of a novel class I allele was predicted, and a panel of candidate CTL epitopes was synthesized whose functional significance was examined using ELISpot and Cr release assays. RESULTS: Class I HLA-A and B frequencies within the cohort are presented. Two novel class I alleles were found, HLA-B*4415 and HLA-Cw*0407. These two class I alleles were relatively common, both in the CSW cohort (2.1% and 3.3% respectively) and in a cohort of lower risk women (1.9% and 3.8% respectively). Allele HLA-B*4415 restricted CTL responses against a novel epitope (EEKAFSPEV) derived from p24 of clade A HIV-1, and HLA-Cw0407 restricted CTL against a predefined HLA-Cw*0401 gp120 epitope. CONCLUSIONS: Multi-epitope vaccine design requires knowledge of HLA class I distribution and HIV CTL epitope characterization in potential target populations. The description of two novel HLA class I alleles at high frequency in this high risk Kenyan CSW cohort suggests that HLA mapping of vaccine cohorts and subsequent characterization of local CTL epitopes will be warranted prior to vaccine trials.

Association between cervical shedding of herpes simplex virus and HIV-1.

OBJECTIVE: To investigate the association between the cervical shedding of herpes simplex virus (HSV) and HIV-1. DESIGN: A cross-sectional study on 200 women seropositive for both HSV-2 and HIV-1 was conducted in a family planning clinic at the Coast Provincial General Hospital, Mombasa, Kenya. MAIN OUTCOME MEASURES: Quantities of HSV DNA (types 1 and 2) and HIV-1 RNA as well as the presence or absence of HIV-1 proviral DNA in cervical secretions were determined and compared. RESULTS: There was a significant correlation between the quantities of HSV DNA and HIV-1 RNA in the cervical secretions of HSV-shedding women (Pearson's r = 0.24, P = 0.05). A 10-fold increase in the quantity of cervical HSV DNA was associated with 1.35-fold higher cervical HIV-1-RNA levels (95% CI 1.00-1.81; P = 0.05), and with 1.36-fold greater odds of detection of HIV-1 proviral DNA (95% CI 1.05-1.75; P = 0.02). CONCLUSION: Higher levels of cervical HSV were associated with higher levels of expressed HIV-1 and with the more frequent detection of HIV-1-infected cells in cervical secretions. Prospective studies are needed to explore further the association between non-ulcerative cervical HSV reactivation and HIV-1 shedding. Such a relationship may have important implications for interventions designed to slow the spread of HIV-1.

Cross-reactive cytotoxic T lymphocytes against a HIV-1 p24 epitope in slow progressors with B*57.

OBJECTIVES: To determine whether CD8 T lymphocytes from HIV-1-infected patients expressing B*5701 and B*5703 show broad cross-reactivity against different variants of a conserved p24 epitope, which might account for the good prognosis of HIV-1-infected individuals with HLA-B*57. DESIGN: B*5701+ and B*5703+ were recruited from Nairobi, Kenya and from Oxford, UK. All patients had been HIV positive for at least 8 years and could be categorized as slow progressors. METHODS: CD8 cytotoxic T cell clones were generated from B*5701+ and B*5703+ donors and tested for their ability to recognize clade variants of an index p24 epitope in standard cytolytic assays. Cross-reactive responses in freshly isolated peripheral blood mononuclear cells (PBMC) were assessed by interferon-gamma (IFNgamma) production and tetramer binding. RESULTS: Broad cross-clade reactivity for both cytolysis and tetramer binding was observed in CD8 T cell clones from patients harbouring the index epitope sequence. Patterns of cross-reactivity were similar in freshly isolated PBMC but varied between individuals in terms of strength and breath of responses generated. One common variant induced an unusual response with tetramer binding but often failed to induce IFNgamma production, and another was a weak stimulator of both IFNgamma and cytolytic activity. CONCLUSION: B*5701+ and B5703+ donors demonstrate broad functional cross-reactivity to both common and rare variants of a dominant p24 epitope, which could be relevant to the association of B*57 alleles with slow progression to AIDS.

Use of serum retinol-binding protein for prediction of vitamin A deficiency: effects of HIV-1 infection, protein malnutrition, and the acute phase response.

BACKGROUND: Serum retinol is the most commonly used indicator of vitamin A status. Retinol is transported in a 1-to-1 complex with retinol-binding protein (RBP). RBP is easy and inexpensive to measure, and studies have shown a high correlation between concentrations of RBP and concentrations of retinol. The performance of RBP in the context of infection or protein malnutrition, however, has not been evaluated. OBJECTIVE: Our aim was to determine whether RBP is a good surrogate measure for retinol in the context of HIV-1 infection, protein malnutrition, and the acute phase response. DESIGN: The relation between RBP and retinol was examined in a cross-sectional study of 600 Kenyan women. RESULTS: There was a high correlation between concentrations of RBP and those of retinol (r = 0.88). When equimolar cutoffs were used, RBP predicted marginal vitamin A status (retinol < 1.05 micro mol/L) with 93% sensitivity and 75% specificity and vitamin A deficiency (retinol < 0.70 micro mol/L) with 91% sensitivity and 94% specificity. Similarly high sensitivities and specificities were found among subgroups with HIV-1 infection, a positive acute phase response, and protein malnutrition. Protein malnutrition and a positive acute phase response were common, especially among HIV-1-infected women, and were independently and synergistically associated with lower RBP concentrations. CONCLUSIONS: Equimolar RBP cutoffs predict vitamin A deficiency with high sensitivity and specificity, even in the context of infection and protein malnutrition. Like retinol, RBP may not accurately identify true vitamin A status under all conditions, because the acute phase response and protein malnutrition depress RBP concentrations. However, RBP may be a simple, inexpensive tool for assessment of vitamin A deficiency in population studies.

Construction of an infectious HIV type 1 molecular clone from an African patient with a subtype D/C Recombinant Virus.

The majority of HIV-1 infections worldwide occur in Africa, where subtype B viruses are rare and intersubtype recombinants are common. Pathogenesis and vaccine studies need to focus on viruses derived from African patients, and infectious HIV-1 molecular clones can be useful tools. To clone non-B subtypes and recombinant viruses from patients, we cultivated HIV-1 from the plasma of a Kenyan long-term survivor. Viral DNA was cloned into a plasmid, which was transfected into COS cells; progeny virus was propagated in PBMCs. Sequence analyses revealed that both the patient's plasma HIV-1 RNA and the cloned DNA genomes were recombinants between subtypes D and C; subtype C sequences comprised the nef and LTR regions. The cloned virus used the CCR5 coreceptor and did not form syncytia in vitro. This infectious HIV-1 subtype D/C recombinant molecular clone obtained from a Kenyan long-term survivor promises to be useful to study pathogenesis and vaccine design.

Human herpesvirus 8 seroconversion in Kenyan women by enzyme-linked immunosorbent assay and immunofluorescence assay.

BACKGROUND: Human herpesvirus 8 (HHV-8) antibody tests vary in reported sensitivity and specificity, depending on the population tested and the assay. OBJECTIVE: The purpose of this study was to compare the ability to detect seroconversion to HHV-8 in a cohort of HHV-8 seronegative female commercial sex workers in Kenya using three tests: HHV-8 viral lysate-based enzyme-linked immunosorbent assay (ELISA), an immunofluorescence assay for HHV-8 lytic antigens (IFA-lytic) and IFA for latent nuclear antigens (IFA-LANA). STUDY DESIGN: By ELISA, 16 women from a prospective cohort of commercial sex workers were identified as seroconverting to HHV-8. A total of 124 post-enrollment samples from these 16 women as well as the enrollment samples were tested for HHV-8 antibodies by all three assays to monitor seroconversion. RESULTS: Of 16 women with apparent seroconversion by ELISA, 8 had a rise in IFA-lytic titers either concomitant with or prior to the first positive ELISA sample and no initial LANA by IFA. Five of the 16 women were IFA-LANA positive at entry, indicating prior infection with HHV-8. Three women had no evidence of seroconversion by either IFA-lytic or IFA-LANA and two of these three had increased ELISA reactivity concomitant with HIV-1 infection. CONCLUSIONS: Conversion from a negative to a positive ELISA result for HHV-8 antibody indicated seroconversion in only half of the study cohort of 16 women when IFA-lytic and IFA-LANA results were considered. The IFA-lytic assay was more sensitive than ELISA for early antibody responses. The IFA-LANA was positive in some women who had neither IFA-lytic nor ELISA antibodies suggesting it may be a marker for latent infections. Presumptive identification of incident HHV-8 infection by ELISA screening followed by IFA-lytic testing to confirm the positive test and IFA-LANA to rule out prior infection provides the most accurate documentation of HHV-8 seroconversion.

Monthly antibiotic chemoprophylaxis and incidence of sexually transmitted infections and HIV-1 infection in Kenyan sex workers: a randomized controlled trial.

CONTEXT: Sexually transmitted infections (STIs) are common in female sex workers (FSWs) and may enhance susceptibility to infection with human immunodeficiency virus type 1 (HIV-1). OBJECTIVE: To examine regular antibiotic prophylaxis in FSWs as a strategy for reducing the incidence of bacterial STIs and HIV-1. DESIGN, SETTING, AND PARTICIPANTS: Randomized, double-blind, placebo-controlled trial conducted between 1998-2002 among FSWs in an urban slum area of Nairobi, Kenya. Of 890 FSWs screened, 466 who were seronegative for HIV-1 infection were enrolled and randomly assigned to receive azithromycin (n = 230) or placebo (n = 236). Groups were well matched at baseline for sexual risk taking and STI rates. INTERVENTION: Monthly oral administration of 1 g of azithromycin or identical placebo, as directly observed therapy. All participants were provided with free condoms, risk-reduction counseling, and STI case management. MAIN OUTCOME MEASURES: The primary study end point was incidence of HIV-1 infection. Secondary end points were the incidence of STIs due to Neisseria gonorrhoeae, Chlamydia trachomatis, Trichomonas vaginalis, Treponema pallidum, and Haemophilus ducreyi, as well as bacterial vaginosis. Analysis of herpes simplex virus type 2 (HSV-2) infection was performed post hoc. RESULTS: Seventy-three percent of participants (n = 341) were followed up for 2 or more years or until they reached an administrative trial end point. Incidence of HIV-1 did not differ between treatment and placebo groups (4% [19 cases per 473 person-years of follow-up] vs 3.2% [16 cases per 495 person-years of follow-up] rate ratio [RR], 1.2; 95% CI, 0.6-2.5). Incident HIV-1 infection was associated with preceding infection with N gonorrhoeae (rate ratio [RR], 4.9; 95% CI, 1.7-14.3) or C trachomatis (RR, 3.0; 95% CI, 1.1-8.9). There was a reduced incidence in the treatment group of infection with N gonorrhoeae (RR, 0.46; 95% CI, 0.31-0.68), C trachomatis (RR, 0.38; 95% CI, 0.26-0.57), and T vaginalis (RR, 0.56; 95% CI, 0.40-0.78). The seroprevalence of HSV-2 infection at enrollment was 72.7%, and HSV-2 infection at baseline was independently associated with HIV-1 acquisition (RR, 6.3; 95% CI, 1.5-27.1). CONCLUSIONS: Despite an association between bacterial STIs and acquisition of HIV-1 infection, the addition of monthly azithromycin prophylaxis to established HIV-1 risk reduction strategies substantially reduced the incidence of STIs but did not reduce the incidence of HIV-1. Prevalent HSV-2 infection may have been an important cofactor in acquisition of HIV-1.

Safety and immunogenicity study of Multiclade HIV-1 adenoviral vector vaccine alone or as boost following a multiclade HIV-1 DNA vaccine in Africa.

BACKGROUND: We conducted a double-blind, randomized, placebo-controlled Phase I study of a recombinant replication-defective adenovirus type 5 (rAd5) vector expressing HIV-1 Gag and Pol from subtype B and Env from subtypes A, B and C, given alone or as boost following a DNA plasmid vaccine expressing the same HIV-1 proteins plus Nef, in 114 healthy HIV-uninfected African adults. METHODOLOGY/PRINCIPAL FINDINGS: Volunteers were randomized to 4 groups receiving the rAd5 vaccine intramuscularly at dosage levels of 1×10(10) or 1×10(11) particle units (PU) either alone or as boost following 3 injections of the DNA vaccine given at 4 mg/dose intramuscularly by needle-free injection using Biojector® 2000. Safety and immunogenicity were evaluated for 12 months. Both vaccines were well-tolerated. Overall, 62% and 86% of vaccine recipients in the rAd5 alone and DNA prime - rAd5 boost groups, respectively, responded to the HIV-1 proteins by an interferon-gamma (IFN-γ) ELISPOT. The frequency of immune responses was independent of rAd5 dosage levels. The highest frequency of responses after rAd5 alone was detected at 6 weeks; after DNA prime - rAd5 boost, at 6 months (end of study). At baseline, neutralizing antibodies against Ad5 were present in 81% of volunteers; the distribution was similar across the 4 groups. Pre-existing immunity to Ad5 did not appear to have a significant impact on reactogenicity or immune response rates to HIV antigens by IFN-γ ELISPOT. Binding antibodies against Env were detected in up to 100% recipients of DNA prime - rAd5 boost. One volunteer acquired HIV infection after the study ended, two years after receipt of rAd5 alone. CONCLUSIONS/SIGNIFICANCE: The HIV-1 rAd5 vaccine, either alone or as a boost following HIV-1 DNA vaccine, was well-tolerated and immunogenic in African adults. DNA priming increased the frequency and magnitude of cellular and humoral immune responses, but there was no effect of rAd5 dosage on immunogenicity endpoints. TRIAL REGISTRATION: ClinicalTrials.gov NCT00124007.

An evaluation of intravaginal rings as a potential HIV prevention device in urban Kenya: behaviors and attitudes that might influence uptake within a high-risk population.

PURPOSE: We sought to assess the potential acceptability of intravaginal rings (IVRs) as an HIV prevention method among at-risk women and men. METHODS: We conducted a qualitative assessment of initial attitudes toward IVRs, current HIV prevention methods, and common behavioral practices among female sex workers (FSWs) and men who frequent FSWs in Mukuru, an urban slum community in Nairobi, Kenya. Nineteen women and 21 men took part in six focus group discussions. RESULTS: Most participants, both male and female, responded positively to the concept of an IVR as a device for delivering microbicides. Women particularly liked the convenience offered by its slow-release capacity. Some female respondents raised concerns about whether male customers would discover the ring and respond negatively, whereas others thought it unlikely that their clients would feel the ring. Focus groups conducted with male clients of FSWs suggested that many would be enthusiastic about women, and particularly sex workers, using a microbicide ring, but that women's fears about negative responses to covert use were well founded. Overall, this high-risk population of FSWs and male clients in Nairobi was very open to the IVR as a potential HIV prevention device. CONCLUSION: Themes that emerged from the focus groups highlight the importance of understanding attitudes toward IVRs as well as cultural practices that may impact IVR use in high-risk populations when pursuing clinical development of this potential HIV prevention device.

HIV-1 neutralizing activity is correlated with increased levels of chemokines in saliva of HIV-1-exposed uninfected individuals.

AIM: Mucosal HIV-1 exposure stimulates a variety of mucosal immune responses, including IgA1-mediated virus neutralization, even in the absence of an established infection. We hypothesized that other immune molecules might also contribute to the HIV-1 neutralizing activity observed in the mucosal secretions of HIV-1 exposed uninfected individuals. METHODS: Saliva samples were collected from HIV-1 seronegative high-risk female sex workers (FSW) from Nairobi. Samples were also collected from HIV-1 IgG positive FSW and HIV-1 IgG negative low-risk women from the same geographical area. In all samples, IgA2, secretory leukocyte protease inhibitor (SLPI), regulated on activation, normal T-cell expressed and secreted (RANTES), macrophage inflammatory protein 1 alpha and beta (MIP-1alpha and -beta) and monocyte chemoattractant protein-1 (MCP-1) were quantified. The IgA1-depleted saliva samples were subsequently tested for neutralizing capacity in a PBMC-based neutralization assay using a primary HIV-1 clade A isolate to determine biological relevance of the measured molecules. RESULTS: HIV-1 specific neutralization was present in the IgA1-depleted fraction from saliva of both HIV-1 seropositive (9 of 10) and high-risk individuals (36 of 45) but not in HIV-1 IgG-negative control subjects (0 of 8). In the high-risk individuals, higher levels of CC-chemokines were seen in those that could neutralize HIV-1 as compared with those that could not (P<0.05). CONCLUSION: The HIV-1 neutralizing activity in saliva of HIV-1-exposed high-risk individuals is not only mediated by IgA1, but is also present in IgA1-depleted fractions and is associated with increased levels of CC-chemokines. Such innate immune factors may be important in limiting HIV-1 mucosal transmission.