Genetic subtypes of HIV type 1 and HIV type 2 strains in commercial sex workers from Bamako, Mali

Immunity in the Cervix: Interphase between Immune and Cervical Epithelial Cells

The cervix is divided into two morphologically and immunologically distinct regions, namely, (1) the microbe-laden ectocervix, which is proximal to the vagina, and (2) the "sterile" endocervix, which is distal to the uterus. The two cervical regions are bordered by the cervical transformation zone (CTZ), an area of changing cells, and are predominantly composed of cervical epithelial cells. Epithelial cells are known to play a crucial role in the initiation, maintenance, and regulation of innate and adaptive response in collaboration with immune cells in several tissue types, including the cervix, and their dysfunction can lead to a spectrum of clinical syndromes. For instance, epithelial cells block progression and neutralize or kill microorganisms through multiple ways. These (ways) include mounting physical (intercellular junctions, secretion of mucus) and immune barriers (pathogen-recognition receptor-mediated pathways), which collectively and ultimately lead to the release of specific chemokines and or cytokines. The cytokines subsequently recruit subsets of immune cells appropriate to a particular immune context and response, such as dendritic cells (DCs), T, B, and natural killer (NK) cells. The immune response, as most biological processes in the female reproductive tract (FRT), is mainly regulated by estrogen and progesterone and their (immune cells) responses vary during different physiological phases of reproduction, such as menstrual cycle, pregnancy, and post menopause. The purpose of the present review is to compare the immunological profile of the mucosae and immune cells in the ecto- and endocervix and their interphase during the different phases of female reproduction.

Comparison of Follicular and Luteal Phase Mucosal Markers of HIV Susceptibility in Healthy Women

The purpose of this study was to evaluate differences in vaginal immune cell populations, vaginal tissue gene expression, antimicrobial activity of the cervicovaginal (CV) lavage (CVL), vaginal flora, and p24 antigen production from CV tissues after ex vivo human immunodeficiency virus (HIV) infection between follicular (FOL) and luteal (LUT) phases of the menstrual cycle. CV tissue biopsies, CV secretions, and blood samples were obtained as part of two longitudinal clinical trials of healthy women (CONRAD D11-119 and A12-124 studies). Participants (n = 39) were HIV-seronegative women not using exogenous hormone supplementation, with normal menstrual cycles, who were screened to exclude sexually transmitted and reproductive tract infections. Serum levels of estradiol and progesterone were significantly higher in the LUT versus the FOL phase of the menstrual cycle. Controlling for race, reported contraceptive use/sexual practices, and clinical trial, we found no differences in vaginal tissue immune cell populations and activation status, transcriptomes, inhibition of HIV, herpes simplex virus type 2 and Escherichia coli by the CVL, vaginal pH or Nugent score, or production of p24 antigen after ex vivo infection by HIV-1BaL between CV samples obtained in the FOL phase versus the LUT phase of the menstrual cycle. There were no significant correlations between serum estradiol and progesterone levels and CV endpoints. The hypothesis that the LUT phase of the menstrual cycle represents a more vulnerable stage for mucosal infection with HIV was not supported by data from samples obtained from the lower genital tract (ectocervix and vagina) from these two clinical trials.

Profile of the HIV epidemic in Cape Verde: molecular epidemiology and drug resistance mutations among HIV-1 and HIV-2 infected patients from distinct islands of the archipelago

HIV-1 and HIV-2 have been detected in Cape Verde since 1987, but little is known regarding the genetic diversity of these viruses in this archipelago, located near the West African coast. In this study, we characterized the molecular epidemiology of HIV-1 and HIV-2 and described the occurrence of drug resistance mutations (DRM) among antiretroviral therapy naïve (ARTn) patients and patients under treatment (ARTexp) from different Cape Verde islands. Blood samples, socio-demographic and clinical-laboratory data were obtained from 221 HIV-positive individuals during 2010–2011. Phylogenetic and bootscan analyses of the pol region (1300 bp) were performed for viral subtyping. HIV-1 and HIV-2 DRM were evaluated for ARTn and ARTexp patients using the Stanford HIV Database and HIV-GRADE e.V. Algorithm Homepage, respectively. Among the 221 patients (169 [76.5%] HIV-1, 43 [19.5%] HIV-2 and 9 [4.1%] HIV-1/HIV-2 co-infections), 67% were female. The median ages were 34 (IQR = 1–75) and 47 (IQR = 12–84) for HIV-1 and HIV-2, respectively. HIV-1 infections were due to subtypes G (36.6%), CRF02_AG (30.6%), F1 (9.7%), URFs (10.4%), B (5.2%), CRF05_DF (3.0%), C (2.2%), CRF06_cpx (0.7%), CRF25_cpx (0.7%) and CRF49_cpx (0.7%), whereas all HIV-2 infections belonged to group A. Transmitted DRM (TDRM) was observed in 3.4% (2/58) of ARTn HIV-1-infected patients (1.7% NRTI, 1.7% NNRTI), but not among those with HIV-2. Among ARTexp patients, DRM was observed in 47.8% (33/69) of HIV-1 (37.7% NRTI, 37.7% NNRTI, 7.4% PI, 33.3% for two classes) and 17.6% (3/17) of HIV-2-infections (17.6% NRTI, 11.8% PI, 11.8% both). This study indicates that Cape Verde has a complex and unique HIV-1 molecular epidemiological scenario dominated by HIV-1 subtypes G, CRF02_AG and F1 and HIV-2 subtype A. The occurrence of TDRM and the relatively high level of DRM among treated patients are of concern. Continuous monitoring of patients on ART, including genotyping, are public policies to be implemented.

Epidemiology of HIV among female sex workers, their clients, men who have sex with men and people who inject drugs in West and Central Africa

Introduction

The West and Central Africa (WCA) sub-region is the most populous region of sub-Saharan Africa (SSA), with an estimated population of 356 million living in 24 countries. The HIV epidemic in WCA appears to have distinct dynamics compared to the rest of SSA, being more concentrated among key populations such as female sex workers (FSWs), men who have sex with men (MSM), people who inject drugs (PWID) and clients of FSWs. To explore the epidemiology of HIV in the region, a systematic review of HIV literature among key populations in WCA was conducted since the onset of the HIV epidemic.

Methods

We searched the databases PubMed, CINAHL and others for peer-reviewed articles regarding FSWs, MSM and PWID in 24 countries with no date restriction. Inclusion criteria were sensitive and focused on inclusion of any HIV prevalence data among key populations. HIV prevalence was pooled, and in each country key themes were extracted from the literature.

Results

The search generated 885 titles, 214 abstracts and 122 full articles, of which 76 met inclusion and exclusion criteria providing HIV prevalence data. There were 60 articles characterizing the burden of disease among FSWs, eight for their clients, one for both, six for MSM and one for PWID. The pooled HIV prevalence among FSWs was 34.9% (n=14,388/41,270), among their clients was 7.3% (n=435/5986), among MSM was 17.7% (n=656/3714) and among PWID from one study in Nigeria was 3.8% (n=56/1459).

Conclusions

The disproportionate burden of HIV among FSWs appears to be consistent from the beginning of the HIV epidemic in WCA. While there are less data for other key populations such as clients of FSWs and MSM, the prevalence of HIV is higher among these men compared to other men in the region. There have been sporadic reports among PWID, but limited research on the burden of HIV among these men and women. These data affirm that the HIV epidemic in WCA appears to be far more concentrated among key populations than the epidemics in Southern and Eastern Africa. Evidence-based HIV prevention, treatment and care programmes in WCA should focus on engaging populations with the greatest burden of disease in the continuum of HIV care.

Comparative Evaluation of HIV-1 Neutralization in External Secretions and Sera of HIV-1-Infected Women

Objectives:

Although human immunodeficiency virus type 1 (HIV-1)-specific antibodies are detectable in external secretions by ELISA and western blot (WB), the presence of HIV-1 neutralizing antibodies is difficult to evaluate due to the low levels of immunoglobulins (Ig) and the presence of humoral factors of innate immunity. The objective of this study was to determine virus neutralization activity and the relative contribution of HIV-1-specific antibodies of various isotypes to virus neutralization in serum/plasma samples, cervicovaginal lavages (CVL), and rectal lavages (RL).

Design:

Serum/plasma, CVL, and RL samples were examined by ELISA, WB and HIV-1 neutralization assays. Selected samples were Ig depleted and analyzed for virus neutralization.

Results:

IgG specific for three HIV-1 ENV antigens was detected in all serum/plasma samples, while IgA to at least one ENV glycoprotein was found at the low levels in 95% samples. Serum/plasma samples had the ability to neutralize at least one of three clade B and two clade C viruses. The neutralizing titers were reduced significantly or became undetectable after IgG removal. In corresponding CVL and RL, HIV-1 ENV-specific IgG antibodies were readily detected compared to IgA. Furthermore, IgG in CVL had greater ability than IgA to reduce virus infectivity. The difference in HIV-1 neutralization before and after Ig depletion was not observed in RL, implying that innate humoral factors were involved in anti-HIV-1 activity.

Conclusions:

Results demonstrate that HIV-1-specific neutralizing antibodies are almost exclusively of the IgG isotype in serum/plasma and CVL samples. HIV-1-specific binding antibodies detected in RL are not responsible for neutralization activity, suggesting that the antibody-mediated virus neutralization in external secretions should be verified by means of a selective depletion of Ig.

Systematic review examining differences in HIV, sexually transmitted infections and health-related harms between migrant and non-migrant female sex workers

OBJECTIVES

To assess the evidence of differences in the risk of HIV, sexually transmitted infections (STI) and health-related behaviours between migrant and non-migrant female sex workers (FSWs).

METHODS

Systematic review of published peer-reviewed articles that reported data on HIV, STIs or health-related harms among migrant compared with non-migrant FSWs. Studies were mapped to describe their methods and focus, with a narrative synthesis undertaken to describe the differences in outcomes by migration status overall and stratified by country of origin. Unadjusted ORs are presented graphically to describe differences in HIV and acute STIs among FSWs by migration and income of destination country.

RESULTS

In general, migrant FSWs working in lower-income countries are more at risk of HIV than non-migrants, but migrants working in higher-income countries are at less risk. HIV prevalence was higher among migrant FSWs from Africa in high-income countries. Migrant FSWs in all countries are at an increased risk of acute STIs. Study designs, definitions of FSWs and recruitment methods are diverse. Behavioural data focussed on sexual risks.

DISCUSSION

The lack of consistent differences in risk between migrants and non-migrants highlights the importance of the local context in mediating risk among migrant FSWs. The higher prevalence of HIV among some FSWs originating from African countries is likely to be due to infection at home where HIV prevalence is high. There is a need for ongoing monitoring and research to understand the nature of risk among migrants, how it differs from that of local FSWs and changes over time to inform the delivery of services.

Phylogeographical footprint of colonial history in the global dispersal of human immunodeficiency virus type 2 group A

Human immunodeficiency virus type 2 (HIV-2) emerged in West Africa and has spread further to countries that share socio-historical ties with this region. However, viral origins and dispersal patterns at a global scale remain poorly understood. Here, we adopt a Bayesian phylogeographic approach to investigate the spatial dynamics of HIV-2 group A (HIV-2A) using a collection of 320 partial pol and 248 partial env sequences sampled throughout 19 countries worldwide. We extend phylogenetic diffusion models that simultaneously draw information from multiple loci to estimate location states throughout distinct phylogenies and explicitly attempt to incorporate human migratory fluxes. Our study highlights that Guinea-Bissau, together with Côte d'Ivoire and Senegal, have acted as the main viral sources in the early stages of the epidemic. We show that convenience sampling can obfuscate the estimation of the spatial root of HIV-2A. We explicitly attempt to circumvent this by incorporating rate priors that reflect the ratio of human flow from and to West Africa. We recover four main routes of HIV-2A dispersal that are laid out along colonial ties: Guinea-Bissau and Cape Verde to Portugal, Côte d'Ivoire and Senegal to France. Within Europe, we find strong support for epidemiological linkage from Portugal to Luxembourg and to the UK. We demonstrate that probabilistic models can uncover global patterns of HIV-2A dispersal providing sampling bias is taken into account and we provide a scenario for the international spread of this virus.

Frequency of human immunodeficiency virus type-2 in hiv infected patients in Maputo City, Mozambique

The HIV/AIDS pandemic is primarily caused by HIV-1. Another virus type, HIV-2, is found mainly in West African countries. We hypothesized that population migration and mobility in Africa may have facilitated the introduction and spreading of HIV-2 in Mozambique. The presence of HIV-2 has important implications for diagnosis and choice of treatment of HIV infection. Hence, the aim of this study was to estimate the prevalence of HIV-2 infection and its genotype in Maputo, Mozambique.HIV-infected individuals (N = 1,200) were consecutively enrolled and screened for IgG antibodies against HIV-1 gp41 and HIV-2 gp36 using peptide-based enzyme immunoassays (pepEIA). Specimens showing reactivity on the HIV-2 pepEIA were further tested using the INNO-LIA immunoblot assay and HIV-2 PCR targeting RT and PR genes. Subtype analysis of HIV-2 was based on the protease gene.After screening with HIV-2 pepEIA 1,168 were non-reactive and 32 were reactive to HIV-2 gp36 peptide. Of this total, 30 specimens were simultaneously reactive to gp41 and gp36 pepEIA while two samples reacted solely to gp36 peptide. Only three specimens containing antibodies against gp36 and gp105 on the INNO-LIA immunoblot assay were found to be positive by PCR to HIV-2 subtype A.The proportion of HIV-2 in Maputo City was 0.25% (90%CI 0.01-0.49). The HIV epidemic in Southern Mozambique is driven by HIV-1, with HIV-2 also circulating at a marginal rate. Surveillance program need to improve HIV-2 diagnosis and consider periodical survey aiming to monitor HIV-2 prevalence in the country.

Dual infection with HIV-1 and HIV-2: double trouble or destructive interference?

HIV-1 and HIV-2 are two related retroviruses and, in regions where both infections are endemic, HIV-1/2 dual infection can occur. Several important questions arise about the interplay between these two viruses in a single host, including: what is the potential for HIV-1–HIV-2 recombinants to form, are there synergistic or inhibitory mechanisms that result in distinct viral replication dynamics when compared with HIV-1 or HIV-2 monoinfected individuals and what are the factors to consider when choosing antiretroviral regimes in HIV-1/2 dual-infected individuals? We summarize the relevant evidence to answer these questions, as well as indentify trends in prevalence and how the natural history of HIV-1/2 dual infection differs from that of HIV-1 or HIV-2 monoinfection. The epidemiological and in vitro evidence pertaining to the question of whether HIV-2 infection may protect against HIV-1 superinfection will also be addressed.

Identification and characterization of CRF02_AG, CRF06_cpx, and CRF09_cpx recombinant subtypes in Mali, West Africa

Abstract Multiple HIV-1 subtypes and circulating recombinant forms (CRFs) are known to cocirculate in Africa. In West Africa, the high prevalence of CRF02_AG, and cocirculation of subtype A, CRF01_AE, CRF06_cpx, and other complex intersubtype recombinants has been well documented. Mali, situated in the heart of West Africa, is likely to be affected by the spread of recombinant subtypes. However, the dynamics of the spread of HIV-1 recombinant subtypes as well as nonrecombinant HIV-1 group M subtypes in this area have not been systematically assessed. Herein, we undertook genetic analyses on full-length env sequences derived from HIV-1-infected individuals living in the capital city of Mali, Bamako. Of 23 samples we examined, 16 were classified as CRF02_AG and three had a subsubtype A3. Among the remaining HIV-1 strains, CRF06_cpx and CRF09_cpx were each found in two patients. Comparison of phylogenies for six matched pol and full-length env sequences revealed that two strains had discordant subtype/CRF designations between the pol and env regions: one had A3(pol)CRF02_AG(env) and the other had CRF02_AG(pol)A3(env). Taken together, our study demonstrated the high prevalence of CRF02_AG and complexity of circulating HIV-1 strains in Mali. It also provided evidence of ongoing virus evolution of CRF02_AG, as illustrated by the emergence of more complex CRF02_AG/A3 intersubtype recombinants in this area.

Behaviour change and competitive exclusion can explain the diverging HIV-1 and HIV-2 prevalence trends in Guinea-Bissau

The aim of this study was to determine whether a temporary rise in sexual risk behaviour during war in Guinea-Bissau could explain the observed trends in HIV-1 and HIV-2 prevalence, and to explore the possible contribution of competitive elimination of HIV-2 by HIV-1. A simulation model of the heterosexual transmission of sexually transmitted infections was parameterized using demographic, behavioural and epidemiological data from rural Guinea-Bissau, and fitted to the observed HIV-1 and HIV-2 trends with and without a historic rise in risk behaviour. The observed trends could only be simulated by assuming a temporary rise in risk behaviour. Around 30% of the projected decline in HIV-2 prevalence from a peak of 8.7% to 4.3% in 2010 was due to competitive elimination by HIV-1. Importantly for public health, HIV-1 prevalence was predicted to continue increasing and to become the dominant HIV type by 2010. Data collection is required to validate this prediction.

Infection of macrophages and dendritic cells with primary R5-tropic human immunodeficiency virus type 1 inhibited by natural polyreactive anti-CCR5 antibodies purified from cervicovaginal secretions

Heterosexual contact is the primary mode of human immunodeficiency virus (HIV) type 1 (HIV-1) transmission worldwide. The chemokine receptor CCR5 is the major coreceptor that is associated with the mucosal transmission of R5-tropic HIV-1 during sexual intercourse. The CCR5 molecule is thus a target for antibody-based therapeutic strategies aimed at blocking HIV-1 entry into cells. We have previously demonstrated that polyreactive natural antibodies (NAbs) from therapeutic preparations of immunoglobulin G and from human breast milk contain NAbs directed against CCR5. Such antibodies inhibit the infection of human macrophages and T lymphocytes by R5-tropic isolates of HIV in vitro. In the present study, we demonstrate that human immunoglobulins from the cervicovaginal secretions of HIV-seronegative or HIV-seropositive women contain NAbs directed against the HIV-1 coreceptor CCR5. Natural affinity-purified anti-CCR5 antibodies bound to CCR5 expressed on macrophages and dendritic cells and further inhibited the infection of macrophages and dendritic cells with primary and laboratory-adapted R5-tropic HIV but not with X4-tropic HIV. Natural anti-CCR5 antibodies moderately inhibited R5-tropic HIV transfer from monocyte-derived dendritic cells to autologous T cells. Our results suggest that mucosal anti-CCR5 antibodies from healthy immunocompetent donors may hamper the penetration of HIV and may be suitable for use in the development of novel passive immunotherapy regimens in specific clinical settings of HIV infection.

Susceptibility of middle adolescent females to sexually transmitted infections: impact of hormone contraception and sexual behaviors on vaginal immunity

PROBLEM

The resistance and/or susceptibility to infections can be influenced by patterns of immunomodulators. Based on this and the high rate of sexually transmitted infections (STIs) in adolescents, we examined the longitudinal relationship between sexual behaviors, hormonal contraceptive use, and bacterial vaginosis (BV) with vaginal-associated immunomodulators in adolescent females.

METHOD OF STUDY

Over 27 months, subjects completed detailed questionnaires, and consented to vaginal swabs for STI testing, and vaginal lavages for identification of immunomodulators including T-helper, proinflammatory, and chemokines. Concentrations of immunomodulators were correlated with each parameter together with prevalence of STIs.

RESULTS

Each parameter had a limited influence on vaginal immunomodulators with no evidence of any pattern(s) associated with infection. Conversely, the local presence of proinflammatory cytokines and neutrophils in those with an STI indicated some immune responsiveness.

CONCLUSION

Sexual behaviors, contraceptive usage, and BV do not appear as factors in susceptibility of adolescents to STIs through the influence of local immunomodulators.

Influence of exogenous reproductive hormones on specific antibody production in genital secretions after vaginal vaccination with recombinant cholera toxin B subunit in humans

The objective of this study was to investigate the influence of exogenous reproductive hormones on the local and systemic production of specific immunoglobulin A (IgA) and IgG antibodies after vaginal vaccination with recombinant cholera toxin subunit B (CTB). Three groups of women using either progesterone-containing intrauterine devices (n=9), oral contraceptives (n=8), or no hormonal contraceptive methods (n=9) were vaginally immunized twice, 2 weeks apart. Cervical secretions, vaginal fluids, and serum were collected before and after vaccination. Total and CTB-specific IgA and IgG antibodies in genital secretions and serum were analyzed by enzyme-linked immunosorbent assay. A majority of the women presented strong CTB-specific IgA and IgG antibody responses in cervicovaginal secretions after vaccination, whereas the antitoxin responses in serum were weaker. Exogenously administered steroid hormones did not seem to have any impact on the production of specific antibodies. Both the frequencies and the magnitudes of IgA and IgG antitoxin responses in genital secretions were comparable among the three immunization groups. An association, in particular for IgA, was found between the magnitudes of the CTB-specific antibody responses in cervical secretions and vaginal fluids after vaccination. The sensitivities and positive predictive values of vaginal antibody analyses to reflect responses in cervical secretions were also high, suggesting that vaginal fluids alone might be used for evaluation of genital immune responses in large-scale vaccination studies in the future.

Kinetics of local and systemic immune responses after vaginal immunization with recombinant cholera toxin B subunit in humans

Vaginal vaccination seems to be the best strategy for inducing specific immunoglobulin A (IgA) and IgG antibody responses in the female genital tract. The relative efficiencies of one, two, and three vaginal doses of recombinant cholera toxin B subunit (CTB) in generating mucosal and systemic immune responses in healthy women were evaluated, and the kinetics of the immune responses were monitored for responding volunteers for up to 12 months after the last vaccination. A single dose of CTB failed to generate CTB-specific IgA antibody responses in cervical secretions. Two vaccinations induced significant increases in IgA antitoxin titers in seven of nine volunteers, and four volunteers also developed IgG antitoxin responses. The magnitudes of the responses were 20-fold for IgA antitoxin and 7.1-fold for IgG antitoxin. A third vaccination did not significantly increase the antitoxin responses, although the frequency of IgG responses was slightly higher than that after the second vaccination. In serum, CTB-specific antibodies were observed already after a single vaccination. However, two vaccinations were required to induce marked IgA as well as IgG antitoxin titer increases in the majority of volunteers. The postvaccination levels of antitoxin antibodies in serum were comparable after two and three vaccinations. At 12 months after vaccination, significantly elevated IgA and IgG antitoxin levels in cervical secretions could still be detected in approximately half of the volunteers who had initially responded to the vaccine. Antitoxin titer increases in serum were found in most of the vaccinees at follow-up.

Bacterial vaginosis - a microbiological and immunological enigma. Review article

The development of bacterial vaginosis (BV) among women of childbearing age and the resulting quantitative and qualitative shift from normally occurring lactobacilli in the vagina to a mixture of mainly anaerobic bacteria is a microbiological and immunological enigma that so far has precluded the formulation of a unifying generally accepted theory on the aetiology and clinical course of BV. This critical review highlights some of the more important aspects of BV research that could help in formulating new basic ideas respecting the biology of BV, not least the importance of the interleukin mediators of local inflammatory responses and the bacterial shift from the normally occurring lactobacilli species: L. crispatus, L. gasseri, L. jensenii, and L. iners to a mixed flora dominated by anaerobic bacteria.

Nigerian HIV type 2 subtype A and B from heterotypic HIV type 1 and HIV type 2 or monotypic HIV type 2 infections

The presence of HIV-2 in Nigeria has been confirmed serologically, but not genetically. To determine the frequency of HIV-2 infections and the dynamics between HIV-1 and HIV-2 in 35 of 36 Nigerian states, 420 blood samples were collected in 1999. Antibodies to HIV-1 and HIV-2 were detected by EIA and seroreactivity was confirmed with the INNO-LIA HIV Line Assay. The frequency of HIV-2 was 4.3% (18 of 420), with 3.8% (16 of 420) HIV-1 and HIV-2 (HIV-1/2) heterotypic and 0.5% (2 of 420) HIV-2 homotypic infections. The presence of HIV-2 subtype B in the two monotypic HIV-2 infections and subtype A in 11 (68.8%) of 16 HIV-1/2 dually seropositive samples was established by sequencing and phylogenetic analysis. HIV-2 subtype B viruses were not found in any of the HIV-1/2 dual infections, and HIV-2 subtype A strains were not identified in either of the two monotypic HIV-2 infections. Since our sample size was small and represented only convenience samples, larger randomized studies will be needed to better understand the dynamics of infection between HIV-1 and different HIV-2 subtypes and to determine whether significant biological differences exist among the HIV- 2 subtypes.

Development and application of a high-throughput HIV type 1 genotyping assay to identify CRF02_AG in West/West Central Africa

In West/West Central Africa, CRF02_AG is the most prevalent HIV-1 strain and circulates in the milieu of rare subtypes, circulating recombinant forms (CRFs), and unique recombinant forms (URFs). The molecular complexity of HIV-1 epidemics in this region and the need to extensively sample large populations, such as in the case of vaccine trials, pose seemingly conflicting requirements between full-genome sequencing and high-throughput low-resolution assays. Here we describe the development and evaluation of a multiregion hybridization assay (MHAcrf02) for the efficient genotyping of CRF02_AG in West/West Central Africa. Subtype A, G, and CRF02_AG-specific fluorescent probes were designed flanking five recombination breakpoints in CRF02_AG and were used in real-time PCRs. A panel representing West/West Central African HIV-1 genetic diversity was evaluated by MHAcrf02. The sample set, previously characterized by full-genome sequencing, included CRF02_AG and CRF02_AG-containing recombinants (n = 28), other subtypes, CRFs, and URFs (n = 34). DNA from peripheral blood mononuclear cells, cocultures, and plasmids was used as template. When the patterns of probe reactivity were evaluated. CRF02_AG was identified with a 100% specificity and sensitivity. In conclusion, MHAcrf02 will permit more efficient characterization of HIV-1 in West/West Central Africa, where CRF02_AG is an important strain. Together with other regional genotyping assays MHAcrf02 will contribute to the development of a global picture of HIV-1 diversity and geographic distribution, providing a strong foundation for intervention, including vaccine development.

Polymorphism and drug-selected mutations in the protease gene of human immunodeficiency virus type 2 from patients living in Southern France

The susceptibility of human immunodeficiency virus type 2 (HIV-2) to protease inhibitors (PI) is largely unknown. We studied HIV-2 protease genes from 21 HIV-2-infected patients who were exposed or not exposed to PI. The aim of this study was (i). to characterize the polymorphism of HIV-2 protease in the absence of drug, (ii). to know whether the HIV-2 protease gene naturally harbors HIV-1 drug resistance codons, and (iii). to identify mutations emerging under PI-selective pressure. Sixty-five HIV-2 RNA or proviral DNA samples were directly sequenced from the plasma or peripheral blood mononuclear cells of 8 patients who had received PI and 13 patients who had never received any antiretroviral. In untreated patients, the highest amino acid variability in HIV-2 protease was observed at positions 14, 40, 43, 46, 65 and 70, and seven codons (10V, 32I, 36I, 46I, 47V, 71V, and 73A) associated with drug resistance in HIV-1 were highly prevalent. In addition, at six positions (positions 7, 46, 62, 71, 90, and 99), the amino acid variability or the amino acid frequencies or both differed significantly in PI-treated and untreated patients, suggesting that mutations 7K-->R, 46V-->I, 62V-->A/T, 71V-->I, 90L-->M and 99L-->F were occurring under PI-selective pressure. At these positions, at least one sample simultaneously harbored both wild-type and mutated codons, while substitutions at positions 62, 71, 90, and 99 were confirmed in a longitudinal analysis. Moreover, the presence of codons 46I and 99F in the absence of drug in HIV-2 subtype B proteases may reflect natural resistance to PI. In conclusion, the present study revealed that HIV-2 strains harbor specific patterns of natural polymorphism and resistance.

Molecular epidemiology of HIV in Ghana: Dominance of CRF02_AG

Recent studies showed the importance of CRF02_AG in West Africa, although the clinical relevance of these recombinant forms of HIV remains unknown. The present study aimed at determining the molecular diversity of HIV in Ghana and investigating the possible epidemiologic advantage of recombinant HIV-1. Plasma samples collected in 1999-2002 from two populations of HIV infected individuals (144 asymptomatic candidate blood donors and 169 AIDS patients) were studied and 249 of them were molecularly characterised in gag, pol, and env regions. Five molecular groups were identified: strains clustering with CRF02_AG in all regions (147/249 or 59%), recombinant strains clustering with CRF02_AG in one or two regions (50/249 or 20%), other subtypes, pure or recombinant, but not involving CRF02_AG (37/249 or 15%), HIV-2 (11/249 or 4.5%), and double infections (4/249 or 1.5%). There was no significant difference in the distribution of HIV-1 recombinant strains according to clinical presentation. No evidence of a significant increase in CRF02_AG prevalence between 1999 and 2002 was found. Irrespective of clinical condition, CRF02_AG is the predominant molecular form of HIV-1 in Kumasi, Ghana.

Evolution and diversity of HIV-1 in Africa--a review

The HIV/AIDS pandemic represents a major development crisis for the African continent, which is the worst affected region in the world. Currently, almost 30 of the 42 million people infected with HIV worldwide live in Africa. AIDS in humans is caused by two lentiviruses, HIV-1 and HIV-2, which entered the human population by zoonotic transmissions from at least two different African primate species. Extensive phylogenetic analyses of partial and full-length genome sequences have helped to gain insights into the evolutionary biology and population dynamics of HIV. One of the major characteristics of HIV is its rapid evolution, which has resulted in substantial genetic diversity amongst different isolates, the majority of which are represented in Africa. Genetic variability of HIV and any consequent phenotypic variation poses a significant challenge to disease control and surveillance in different geographic regions of Africa. This review focuses on the origins and evolution of HIV, current classification and diversity of HIV isolates in Africa and provides an extensive account of the geographic distribution of HIV types, groups, and subtypes in each of the 49 African countries. Numerous epidemiological studies have provided a picture of HIV distribution patterns in most countries in Africa, and these show increasing evidence of the importance of HIV-1 recombinants. In particular, this review highlights that our current understanding of HIV distribution in Africa is incomplete and inadequately represents the diversity of the virus, and underscores the need for ongoing surveillance.

Female sex hormones as regulatory factors in the vaginal immune compartment

Sexually transmitted diseases (STD) are now considered to be among the most common human infections. The incidence of STD is on the rise, which is partly due to frequent transmission during the asymptomatic phase of infection. The compounded cost of STD just in the United States is estimated to exceed $10 billion annually. STD are particularly prevalent in teenagers and young adults and the health problems caused by these diseases tend to be more severe and more frequent in woman than in men. Despite considerable efforts, a vaccine that provides protective immunity against sexually transmitted diseases in humans has not been developed. Nonetheless, research in animal models indicates that strong local and regional immune responses can influence the outcome of vaginal challenge with microbial pathogens. Vaginal immunity is an area of basic immunology that has received relatively little attention, but it is already clear that the mucosal and regional immunology of the vagina has unique features. The present review summarizes some of the anatomical, physiological and immunological features of the vagina and uterus that distinguish humans, non-human primates, rats and mice. These interspecies differences need to be taken into account in laboratory efforts to develop effective vaccines for STD in humans.

Interactions of the female hormonal environment, susceptibility to viral infections, and disease progression

Sex hormones influence susceptibility and disease predisposition for many genital tract infections. This review describes the mechanisms by which sex steroids affect mucosal immunity, with particular reference to human immunodeficiency virus (HIV) and genital herpes, and the stage-specific effects of hormonal contraception on human papillomavirus (HPV) infection. Estrogen's role is important in the early stages of several infections as it stimulates antibody- and cell-mediated immune responses. There is increased expression of some cytokines in peripheral blood and vaginal fluids during the follicular phase of the menstrual cycle and with use of hormonal contraception. Whether estrogen exerts a protective or deleterious influence depends on the infecting organism and stage of infection or disease. Estrogen apparently reduces susceptibility to primary HPV infection but in the event of persistent HPV infection, sex steroid hormones (estrogen and/or progesterone) are associated with progression to cervical cancer. It is important that these stage-specific effects are better described because most vaccines will try to prevent either infection or disease. Clinicians with patients at high risk of sexually transmitted infections, especially HIV, require better information on the risks associated with different hormonal contraceptive regimes.

HIV-1 and HIV-2 seroprevalence and risk factors among hospital outpatients in the Eastern Region of Ghana, West Africa

A cross-sectional study of 854 outpatients seen at three hospitals in the Eastern Region of Ghana, West Africa assessed HIV-1 and HIV-2 seroprevalence rates and associated risk factors. During mid-1999, patients were tested in an anonymous study linked to a questionnaire and abstracted record data in three distinct communities with differing levels of urbanization. Combined HIV seroprevalence rates were 19.2% for Agomanya, the most rural community, 5.1% for Akwatia, and 3.4% for Nkawkaw, the most urbanized community. HIV-1 infection alone accounted for 84.5% of cases, compared with 9.5% and 6.0% for HIV-2 and dual infection, respectively. In a multivariable model, the Agomanya location was significantly associated with HIV status (odds ratio [OR], 7.7; 95% confidence interval [CI], 2.9-20.1; p <.0001). Employed people were also more likely to be infected (OR, 4.3; 95% CI, 1.02-18.3; p =.047). Among prenatal patients, those from Agomanya were more likely to report no live-in partner or spouse compared with Nkawkaw and Akwatia (p <.0001). These findings suggest sexual partner exchange patterns may be more useful in explaining HIV seroprevalence rates than level of community urbanization. Intervention programs directed at these high risk populations for HIV infection in Ghana are urgently needed.

CRF06-cpx: a new circulating recombinant form of HIV-1 in West Africa involving subtypes A, G, K, and J

Phylogenetic analysis of numerous strains of HIV-1 isolated from diverse geographic origins has revealed three distinct groups of HIV-1: groups M, N, and O. Within group M, subtypes, sub-subtypes and circulating recombinant forms (CRFs) exist. Recently, two near-full-length genomes of similar complex mosaic viruses containing fragments of subtypes A, G, I, and J were described in patients from Burkina Faso (BFP-90) and Mali (95ML-84). Here, we report on the characterization of two additional full-length genome sequences with similar mosaic structure in epidemiologically unlinked individuals from Senegal (97SE-1078) and Mali (95ML-127). Phylogenetic and recombinant analysis confirmed that the previously described strains, BFP-90 and 95ML-84, were indeed a new CRF of HIV-1, which we can now designate as CRF06-cpx. This new CRF fits the complex (cpx) designation, because four different subtypes (A, G, K, and J) were involved in the mosaic genome structure. The fragment in the pol gene, which was initially characterized as unknown in the BFP-90 strain and subsequently as subtype I in the 95ML-84 strain, is now, with the recent description of the new K subtype, clearly identified as subtype K. CRF06-cpx circulates in Senegal, Mali, Burkina Faso, Ivory Coast, and Nigeria, although the exact prevalence remains to be determined. Importantly, this new variant has also been documented on other continents (Europe [France] and Australia), showing that these viruses are spreading not only locally but globally.

Response to Neisseria gonorrhoeae by cervicovaginal epithelial cells occurs in the absence of toll-like receptor 4-mediated signaling

Toll-like receptors (TLRs) have recently been identified as fundamental components of the innate immune response to bacterial pathogens. We investigated the role of TLR signaling in immune defense of the mucosal epithelial cells of the lower female genital tract. This site provides first line defense against microbial pathogens while remaining tolerant to a complex biosystem of resident microbiota. Epithelial cells derived from normal human vagina, ectocervix, and endocervix expressed mRNA for TLR1, -2, -3, -5, and -6. However, they failed to express TLR4 as well as MD2, two essential components of the receptor complex for LPS in phagocytes and endothelial cells. Consistent with this, endocervical epithelial cells were unresponsive to protein-free preparations of lipooligosaccharide from Neisseria gonorrhoeae and LPS from Escherichia coli. However, they were capable of responding to whole Gram-negative bacteria and bacterial lysates, as demonstrated by NF-kappaB activation and proinflammatory cytokine production. The presence of soluble CD14, a high-affinity receptor for LPS and other bacterial ligands, enhanced the sensitivity of genital tract epithelial cells to both low and high concentrations of bacteria, suggesting that soluble CD14 can act as a coreceptor for non-TLR4 ligands. These data demonstrate that the response to N. gonorrhoeae and other Gram-negative bacteria at the mucosal surface of the female genital tract occurs in the absence of endotoxin recognition and TLR4-mediated signaling.

Genetic analysis of HIV type 2 from Ghana and Guinea-Bissau, West Africa

The phylogenetic variability of part of the long terminal repeat (LTR) region of HIV-2 strains isolated in 1995 from five individuals residing in Bissau, the capital city of Guinea-Bissau, and collected from seven persons from Kumasi, Ghana in 1996-1997, was analyzed. All Guinean samples and all but one Ghanaian sample clustered with HIV-2 subtype A. One Ghanaian sample (14%) was classified as HIV-2 subtype B. This study adds to previous reports on HIV-2 subtype distribution in West Africa indicating local prevalence of HIV-2 subtype B in Ivory Coast and neighboring Ghana.

Sequence specificity of the human immunodeficiency virus type 2 (hiv-2) long terminal repeat u3 region in vivo allows subtyping of the principal hiv-2 viral subtypes a and b

Sequences from the nef/LTR overlap region of the human immunodeficiency virus type 2 (HIV-2) genome were amplified from uncultured peripheral blood mononuclear cells (PBMCs) from 40 HIV-2-infected individuals in The Gambia, West Africa. Additional sequences from the plasma of three blood donors were also derived. Analysis of HIV-2 U3 LTR transcription factor elements (PuB-1, p-ets, PuB-2, peri-kappa B, and NF-kappa B sites) indicated a relatively high level of conservation in vivo. The region immediately 3' of the nef termination codon, which exhibits clade-dependent specificity, was targeted by PCR to differentiate HIV-2 subtype A from subtype B infections, the two principal clinical HIV-2 subtypes. All clinical samples analyzed (n = 43) from The Gambia were identified as HIV-2 subtype A by a combination of LTR sequence analysis and subtype-specific amplification of subtypes A and B. Differential PCR amplification of the HIV-2 U3 LTR region represents a rapid means of differentiating subtype A from subtype B infections, the two dominant HIV-2 subtypes that are important in human disease.

Immunotherapy of hormone-refractory prostate cancer with antigen-loaded dendritic cells

PURPOSE

Provenge (Dendreon Corp, Seattle, WA) is an immunotherapy product consisting of autologous dendritic cells loaded ex vivo with a recombinant fusion protein consisting of prostatic acid phosphatase (PAP) linked to granulocyte-macrophage colony-stimulating factor. Sequential phase I and phase II trials were performed to determine the safety and efficacy of Provenge and to assess its capacity to break immune tolerance to the normal tissue antigen PAP.

PATIENTS AND METHODS

All patients had hormone-refractory prostate cancer. Dendritic-cell precursors were harvested by leukapheresis in weeks 0, 4, 8, and 24, loaded ex vivo with antigen for 2 days, and then infused intravenously over 30 minutes. Phase I patients received increasing doses of Provenge, and phase II patients received all the Provenge that could be prepared from a leukapheresis product.

RESULTS

Patients tolerated treatment well. Fever, the most common adverse event, occurred after 15 infusions (14.7%). All patients developed immune responses to the recombinant fusion protein used to prepare Provenge, and 38% developed immune responses to PAP. Three patients had a more than 50% decline in prostate-specific antigen (PSA) level, and another three patients had 25% to 49% decreases in PSA. The time to disease progression correlated with development of an immune response to PAP and with the dose of dendritic cells received.

CONCLUSION

Provenge is a novel immunotherapy agent that is safe and breaks tolerance to the tissue antigen PAP. Preliminary evidence for clinical efficacy warrants further exploration.

Hormonal levels among HIV-1-seropositive women compared with high-risk HIV-seronegative women during the menstrual cycle. Women's Health Study (WHS) 001 and WHS 001a Study Team

There is a paucity of normative data on hormonal levels among HIV-infected women. Hormonal levels may influence fertility and HIV-related immunological and virological factors. The objective of this study was to determine progesterone and estradiol levels during the menstrual cycle in HIV-seropositive women compared with high-risk seronegative women. The study enrolled 55 HIV-infected and 10 high-risk uninfected women with self-reported regular menstrual cycles (25-30-day cycles). Progesterone and estradiol levels were determined on a weekly basis for 8 weeks. The analysis included evaluations from the first complete menstrual cycle for the 54 HIV-infected and 9 uninfected women who had at least one complete cycle. The median age was 35 years for HIV-infected women and 36 years for uninfected women. The median CD4+ count for HIV-seropositive women was 210 cells/mm3. The median menstrual cycle length was 28 days (range 22-49 days) for HIV-infected women and 25 days (range 24-44 days) for uninfected women. The maximum progesterone level during the luteal phase was normal (>3.0 ng/ml) for 52 (96%) of 54 HIV-seropositive women and 7 (78%) of 9 HIV-seronegative women (p = 0.09, Fisher's exact test). The median maximum progesterone level was 12.2 ng/ml in HIV-seropositive women and 7.2 ng/ml in HIV-seronegative women (p = 0.07, Wilcoxon test). The median maximum estradiol value during the follicular phase was 148 pg/ml for HIV-seropositive women and 111 pg/ml for HIV-seronegative women (p = 0.04, Wilcoxon test). Among HIV-infected women, there were no significant differences in progesterone and estradiol levels by antiretroviral therapy, baseline plasma viral load, or median CD4+ cell count. We conclude that HIV-infected women with self-reported normal menstrual cycles have normal levels of progesterone and estradiol during the menstrual cycle.

The impact of the ovulatory cycle on cytokine production: evaluation of systemic, cervicovaginal, and salivary compartments

To understand the impact of the menstrual cycle on immunologic parameters, we measured the level of cytokines and chemokines from plasma, cervicovaginal lavage (CVL), and saliva samples of 6 premenopausal women during the follicular and luteal phases of the ovulatory cycle. We demonstrate that the level of plasma interleukin-8 (IL-8) was 4-fold higher during the follicular phase than the luteal phase (p = 0.004), whereas plasma IL-1beta, IL-4, IL-6, IL-10, interferon-gamma (IFN-gamma), transforming growth factor-beta (TGF-beta), tumor necrosis factor-alpha (TNF-alpha), macrophage inflammatory protein-1alpha (MIP-1alpha), and TNF receptor II (TNFR II) were not altered during the ovulatory cycle. In the vaginal compartment, as measured from CVL samples, the levels of IL-6 and IL-1beta were both 5-fold higher in the follicular than the luteal phase (p = 0.0002 and 0.03, respectively). Salivary cytokine and chemokine samples were similar when measured during the luteal and the follicular phases. Additional analysis of lymphocyte subsets for phenotypic and functional markers indicated that they were not influenced by the ovulatory cycle. Collectively, these data suggest that IL-6, IL-8, and IL-1beta are differentially regulated during the ovulatory cycle.

Absence of specific mucosal antibody responses in HIV-exposed uninfected sex workers from the Gambia

OBJECTIVES

Specific antibodies to HIV envelope that inactivate virus at the mucosal surfaces involved in sexual contact are of interest for the design of a vaccine against HIV-1. It has been suggested that, in frequently HIV-exposed but uninfected individuals, HIV-specific mucosal antibody responses may exist and play a role in resistance against HIV. This study investigated HIV-1 envelope specific mucosal antibody responses in HIV-resistant sex workers in west Africa.

METHODS

A group of 26 exposed uninfected female commercial sex workers from the Gambia, who have had repeated exposures to HIV-1 and HIV-2 were studied. We assessed the presence of vaginal IgA and IgG in vaginal swabs against a range of HIV-1 and HIV-2 envelope presentations and performed HIV-1 neutralization assays.

RESULTS

No significant vaginal IgA or IgG responses against HIV-1 or HIV-2 were detected, and none of the vaginal secretions tested displayed any HIV-1 neutralizing activity.

CONCLUSION

Vaginal antibody responses against HIV were not found in Gambian sex workers who resist HIV infection. Resistance against HIV infection can therefore occur in the absence of specific antibodies against HIV at the genital mucosa. A protective role for HIV-envelope specific IgA in resistance against HIV-1 infection in exposed uninfected individuals as reported in the literature is uncertain.

Genetic characterization of HIV type 1 and type 2 from Bissau, Guinea-Bissau (West Africa)

Previous studies from Guinea-Bissau (West Africa) have demonstrated a unique epidemiology with respect to both HIV-1 and HIV-2 infection. In order to evaluate the prevalence and dynamics of HIV-1 and HIV-2 subtypes in Bissau, the capital city of Guinea-Bissau, a cross-sectional study was set up using serological and molecular techniques. Plasma samples from 103 individuals were screened for HIV-1 and HIV-2 antibodies by ELISA and Western-blot. Seropositive results were confirmed by PCR amplification of proviral sequences in primary peripheral blood mononuclear cells (PBMC) with env and LTR primer sets for HIV-2 and env, LTR and pol primers for HIV-1. A total of 38/103 individuals were HIV-seroreactive (four HIV-1, 15 HIV-2, 19 HIV-1/HIV-2). A total of eight out of 19 dually seropositive specimens showed double PCR amplification of HIV-1 and HIV-2 proviral sequences, accounting for 21% of the infected individuals. In the remaining 11 individuals either HIV-2 or HIV-1 sequences were detected, the majority (n=9) amplifying only HIV-2. These screening data demonstrate a high discrepancy between serology and PCR results for dually seroreactive samples, Western-blot giving an overestimation of double infection. Additionally, HIV-1 strains were subtyped by heteroduplex mobility assay (HMA) on the basis of gp120 sequences. Subtyping of HIV-2 was carried out by DNA sequencing and phylogenetic analysis of env V3 molecular clones. For both HIV-1 and HIV-2 strains circulating in Bissau, our results indicate dominance of subtype A.

Distribution of HIV-1 subtypes among HIV-seropositive patients in the interior of Côte d'Ivoire

Limited data exist on the distribution of HIV-1 subtypes in Côte d'Ivoire. The aim of this study is to describe the distribution of genetic subtypes of HIV-1 strains in six regions of Côte d'Ivoire. In 1997, we consecutively collected blood from 172 HIV-1-infected patients from six regional tuberculosis treatment centers. Peripheral blood mononuclear cells (PBMCs) from these people were analyzed by a restriction fragment-length polymorphism (RFLP) assay that involves a sequential endonuclease digestion of a 297-base pair polymerase chain reaction (PCR) fragment; plasma samples were tested by a V3-loop peptide enzyme immunoassay (PEIA). DNA sequencing of the protease or env genes was performed on all samples discordant in the two assays as well as a random sample of the concordant subtyped samples. Of 172 specimens, 3 were PCR-negative, and 169 were putatively classified as subtype A by RFLP. The 3 PCR-negative samples were unequivocally subtyped A by PEIA. Of the 169 RFLP subtype A samples, 159 (94%) were subtyped A by PEIA. Of the 10 discordant samples, PEIA testing classified 3 as subtype C, 2 as D, and 5 as F. Sequencing of the env gene classified these samples as 1 subtype A, 4 Ds, and 5 Gs. Thus, 163 (95%) of the specimens were subtype A, 3 subtype D, 4 subtype G, 1 A/D, and 1 A/G (IbNG) circulating recombinant forms (CRF). In conclusion, most HIV-1-infected tuberculosis patients throughout the interior of Côte d'Ivoire are infected with HIV-1 subtype A, which are very likely the A/G (IbNG) CRF. The uniform distribution of this subtype makes Côte d'Ivoire a potential site for vaccine trials.

Interaction with human immunodeficiency virus (HIV) type 2 predicts HIV type 1 genotype

In West Africa, India, and certain regions of Europe, both human immunodeficiency viruses types 1 and 2 (HIV-1 and HIV-2) are known to cocirculate. To investigate the HIV-1 subtypes involved in dual HIV-1 and HIV-2 infections, we sequenced the envelope C2-V3 region from 29 dually infected female commercial sex workers from Senegal. The majority of women (23 of 29) were infected by HIV-1 subtype A. Within the HIV-1 subtype A sequences, 14 of 23 (60.8%) clustered with the West African associated A/G recombinant form (IbNG), and 9 of 23 (39.2%) formed a separate cluster distinct from the A/G IbNG. In contrast, in HIV-1 singly infected individuals, non-IbNG subtype A was found in only 13 of 98 (13.3%). Therefore, the lack of protection and/or interaction with HIV-2 was associated with a distinct HIV-1 A genotype. These results suggest differences in the biological properties of HIV-1 genotypes and their in vivo interaction with HIV-2.

Genetic analysis of HIV type 2 in monotypic and dual HIV infections

A significant level of genetic variation among HIV-1 and HIV-2 has been described. The interaction of specific HIV-2 subtypes with HIV-1 may serve to identify potential biological properties associated with dual infection. To genetically characterize the HIV-2 strains circulating in Senegal and their relationship to coinfection with HIV-1, we sequenced the HIV-2 envelope C2-C3 region of 12 subjects coinfected with HIV-1 and HIV-2 and 9 subjects singly infected with HIV-2. The phylogenetic analysis showed that all subjects were infected with HIV-2 subtype A, confirming its predominance in West Africa. We did not observe specific sequences or genetic clustering based on coinfection status.

The identification of a complex A/G/I/J recombinant HIV type 1 virus in various West African countries

In this sequence note we describe the full-length genome sequence of an HIV-1 isolate originating from the west African country of Mali. The phylogenetic tree analysis from the near full-length genome shows that the 95ML84 strain forms a separate cluster, supported by 100% of the bootstrap values, with the previously described A/G/J/? mosaic virus BFP90 from Burkina Faso. Additional analysis showed that throughout the genome the lowest diversity was seen between the 95ML84 and the BFP90 viruses, and bootscan analysis showed a similar complex genomic structure. In addition to the initial report describing the BFP90 virus as an A/G/J/? recombinant, our data show that for the BFP90 and 95ML84 strains the unclassified region corresponds to subtype I. The A/G/I/J BFP90 and 95ML84 strains represent the fifth and most complex circulating recombinant form of HIV-1 detected so far, and our data show its presence in various West African countries. Subtype I and J sequences, initially considered rare, seem to have broadened their geographical spread by way of these recombinant forms.

Molecular characterization of human immunodeficiency virus (HIV)-1 and -2 in individuals from guinea-bissau with single or dual infections: predominance of a distinct HIV-1 subtype A/G recombinant in West Africa

Guinea-Bissau in West Africa has the highest prevalence of human immunodeficiency virus (HIV)-2 infection in the world, but recently the HIV-1 prevalence increased rapidly with the subsequent appearance of HIV-1 and HIV-2 dual infections. Information about the genetic subtypes of HIV in the region is limited. Therefore, we characterized the env V3 region of HIV-1 and HIV-2 variants through direct DNA sequencing of peripheral blood mononuclear cell samples from 18 individuals with HIV-1 only and 9 individuals with dual infection. Phylogenetic analyses of these new sequences and database sequences from other West African countries showed that all HIV-1 and HIV-2 sequences from singly as well as dually infected individuals, except one, clustered among HIV-1 subtype A and HIV-2 subtype A, respectively. Importantly, a majority of the HIV-1 sequences from Guinea-Bissau and neighbouring countries were closely related with the isolates IbNG, DJ263, and DJ264, which share a common subtype A/G recombination pattern. Analysis of pol gene sequences from selected HIV-1 variants showed that "IbNG-like" viruses in Guinea-Bissau are also recombinant, indicating that the HIV-1 epidemic in Guinea-Bissau and neighbouring countries is dominated by an epidemic spread of a distinct subtype A/G recombinant, which is strikingly similar to the epidemic spread of a subtype A/E recombinant in Southeast Asia. Furthermore, the HIV-1 and HIV-2 variants carried by individuals with dual infection were intermixed with variants from singly infected individuals, indicating that variants involved in dual and single infections have common epidemiological histories.

Mucosal vaccination strategies for women

Women were immunized orally, rectally, or vaginally with a recombinant cholera toxin B-containing vaccine to determine which of these mucosal immunization routes generate the greatest levels of antibody in the female genital tract and rectum. ELISA was used to measure concentrations of cholera toxin B-specific IgA and IgG antibody in serum and secretions before and after three immunizations. Each immunization route similarly increased specific IgG in serum and specific IgA in saliva. Only the vaginal route increased IgA antibodies in genital tract secretions and could be shown to induce a local IgG response. However, vaginal immunization failed to produce antibody in the rectum. In a similar fashion, rectal immunization elicited highest concentrations of locally derived IgA and IgG antibody in the rectum but was ineffective for generating antibody in the genital tract. The data suggest that local immunization may induce the greatest immune responses in the female genital tract and rectum of humans.

Quantification of RNA in HIV type 1 subtypes D and G by NucliSens and Amplicor assays in Abidjan, Ivory Coast

We have compared the performance of the NucliSens and the standard and modified HIV Monitor assays to quantify HIV-1 RNA plasma viral load in 12 tuberculosis patients infected with HIV-1 env subtype D (n = 3) and env subtype G (n = 9) in Ivory Coast. RNA was quantified in all nine subtype G specimens by the modified Amplicor HIV Monitor (mean, 4.6 log10 copies/ml; range, 3.1-6.3 log10/ml), in seven specimens by NucliSens (mean, 4.4 log10 copies/ml; range, 2.7-5.5 log10 copies/ml), and in 6 specimens by the standard Amplicor HIV Monitor assay (mean, 4.2 log10 copies/ml; range, 3.5-5.0 log10 copies/ml). All three subtype D samples were amplified by both the modified Amplicor HIV Monitor (mean, 4.5 log10 copies/ml; range, 3.8-5.1 log10 copies/ml) and NucliSens (mean, 3.8 log10 copies/ml; range, 2.8-5.0 log10 copies/ml); two samples were quantified by the standard Amplicor HIV Monitor assay (mean, 3.0 log10 copies/ml; range, 2.4-3.6 log10 copies/ml). Our preliminary results suggest that the modified Amplicor HIV Monitor can accurately quantify HIV-1 RNA viral load in persons infected with subtype D and G strains.

Genetic analysis of human immunodeficiency virus in Abidjan, Ivory Coast reveals predominance of HIV type 1 subtype A and introduction of subtype G

To better understand the molecular epidemiology of HIV genetic diversity in Abidjan, Ivory Coast, we performed a genetic analysis of 170 HIV-1-seropositive specimens representing newly diagnosed tuberculosis patients (n = 143) and women monitored in a mother-to-child transmission cohort study (n = 27). Preliminary screening with RFLP presumptively classified 162 (95.3%) of these as subtype A. The envelope region of 108 specimens was subtyped by sequence analysis: 102 (94.4%) were subtype A, 2 (1.9%) were subtype D, and 4 (3.7%) were subtype G. Subtyping gag and env regions of the genome suggested that five of the six nonsubtype A isolates exhibited a potentially mosaic structure. A comparative phylogenetic analysis of HIV-1 subtype A C2V3 from 27 Ivory Coast and 21 Ugandan sequences revealed a striking clustering among Ivory Coast variants, and an independent segregation from Ugandan subtype A. Despite independent clustering with other subtype A specimens, limited variability of the V3 loop apex was observed; the globally predominant V3 motif, GPGQ, represented 90.1% of the HIV-1 strains. This study demonstrates that clade A is the predominant HIV-1 subtype in HIV-seropositive individuals in Abidjan, Ivory Coast and that these strains are phylogenetically distinct from other subtype A strains observed in East Africa.

HIV-2 and T cell recognition

HIV-2 is less pathogenic and less transmissible than HIV-1. Recent research in relation to deletions in the HIV nef gene and to immune cross-reactions between infections by HIV-2, HIV-1 and simian immunodeficiency virus suggests that T cell recognition and the control of viral replication may be more efficient in HIV-2 infection than in HIV-1 infection. These insights may be crucial to the design of effective vaccines.