Selection for human immunodeficiency virus type 1 envelope glycosylation variants with shorter V1-V2 loop sequences occurs during transmission of certain genetic subtypes and may impact viral RNA levels.

Designing an effective human immunodeficiency virus type 1 (HIV-1) vaccine will rely on understanding which variants, from among the myriad of circulating HIV-1 strains, are most commonly transmitted and determining whether such variants have an Achilles heel. Here we show that heterosexually acquired subtype A HIV-1 envelopes have signature sequences that include shorter V1-V2 loop sequences and fewer predicted N-linked glycosylation sites relative to the overall population of circulating variants. In contrast, recently transmitted subtype B variants did not, and this was true for cases where the major risk factor was homosexual contact, as well as for cases where it was heterosexual contact.

Contribution of HIV-1 infection to acquisition of sexually transmitted disease: a 10-year prospective study.

Background: Sexually transmitted diseases (STDs) enhance human immunodeficiency virus (HIV)-1 susceptibility, but few studies have examined the reciprocal effect of HIV-1 on STD acquisition.

Methods: Data from a prospective cohort study conducted among female sex workers in Mombasa, Kenya between 1993 and 2003 were used to determine the effect of HIV-1 infection on STD susceptibility. The cohort included 1215 HIV-1-seronegative women who underwent monthly HIV-1 and STD screening, of whom 238 experienced seroconversion to HIV-1 during follow-up.

Hormonal contraception and risk of cervical infections among HIV-1-seropositive Kenyan women.

Objective: To evaluate the relationship between hormonal contraceptive use and the acquisition of cervical sexually transmitted infections (STI) among HIV-1-infected women.

Design: A prospective cohort study of 242 commercial sex workers in Mombasa, Kenya, followed from the time of HIV-1 infection.

Methods: At monthly follow-up visits, sexual behavior and contraceptive use were recorded, and laboratory screening for STI was performed.

Micronutrient supplementation increases genital tract shedding of HIV-1 in women: results of a randomized trial.

To test the hypothesis that micronutrient supplementation decreases genital HIV-1 shedding, a double-blind, randomized, placebo-controlled trial of 6 weeks of multivitamin plus selenium supplementation vs. placebo was conducted among 400 HIV-1-seropositive, nonpregnant, antiretroviral-naive women in Mombasa, Kenya. Primary outcome measures included cervical and vaginal shedding of HIV-1-infected cells and RNA.

Characterization of virus infectivity and cell-free capsid assembly of SIVMneCL8.

We have previously described a cell-free system that reconstitutes immature capsid assembly of Gag polypeptides from viruses belonging to three major primate lentiviral lineages, including HIV-1, HIV-2 and SIVagm. Studies described here examine a member of the SIVmac/Mne lineage, SIVMneCL8, using assays for virus production and infectivity as well as cellular events in capsid formation. We report that SIVMneCL8, a molecular clone with properties typical of transmitted viral variants, is less infectious per unit p27 Gag than another member of the SIVmac/Mne lineage, SIVmac239.

A real-time PCR-based method to independently sample single simian immunodeficiency virus genomes from macaques with a range of viral loads.

The generation of a diverse population of viral variants is a hallmark of simian immunodeficiency virus (SIV) infection. In order to address what role this diversity plays in disease progression, accurate sampling of the viral population is necessary. However, traditional PCR-based methods often rely on amplification of multiple genomes in one reaction, leading to resampling of viral genomes and potential errors in the estimations of viral diversity, especially when sequences from only one or a small number of PCRs are examined and/or viral copy number is low.

Association of levels of HIV-1-infected breast milk cells and risk of mother-to-child transmission.

Understanding how the level of human immunodeficiency virus type 1 (HIV-1)-infected breast milk cells (BMCs) affects HIV transmission via breast-feeding can shed light on the mechanism of infection and aid in establishing effective interventions. The proportion of infected cells to total cells was measured in serial breast milk samples collected from 291 HIV-1-infected women in Nairobi, Kenya, by use of real-time DNA polymerase chain reaction amplification of BMCs. The number of infected BMCs per million cells was associated with levels of cell-free viral RNA in breast milk (R=.

Predictors of early mortality in a cohort of human immunodeficiency virus type 1-infected african children.

Background: Pediatric human immunodeficiency virus type 1 (HIV-1) infection follows a bimodal clinical course with rapid progression in 10-45% of children before the age of 2 years and slower progression in the remainder. A prospective observational study was undertaken to determine predictors of mortality in HIV-1-infected African infants during the first 2 years of life.

Methods: Infants in a perinatal cohort identified to be HIV-1-infected by DNA PCR were followed monthly to 1 year, then quarterly to 2 years or death.

Human immunodeficiency virus type 1 (HIV-1) diversity at time of infection is not restricted to certain risk groups or specific HIV-1 subtypes.

African women frequently acquire several genetically distinct human immunodeficiency virus type 1 (HIV-1) variants from a heterosexual partner, whereas the acquisition of multiple variants appears to be rare in men. To determine whether newly infected individuals in other risk groups acquire genetically diverse viruses, we examined the viral envelope sequences in plasma samples from 13 women and 4 men from the United States infected with subtype B viruses and 10 men from Kenya infected with non-subtype B viruses. HIV-1 envelope sequences differed by more than 2% in three U.

Cyclic shedding of HIV-1 RNA in cervical secretions during the menstrual cycle.

The association between hormone fluctuations during the menstrual cycle and human immunodeficiency virus type 1 (HIV-1) RNA shedding in cervical and vaginal secretions was examined daily for 17 HIV-1-seropositive women, for the duration of 1 cycle. Serum levels of RNA were evaluated 3 times/week. A marginally significant positive correlation between serum levels of progesterone and serum levels of HIV-1 RNA (P=.

Identification of modifiable factors that affect the genetic diversity of the transmitted HIV-1 population.

Background: Our previous studies have shown that the majority of African women were infected with multiple HIV-1 genetic variants, while in the remaining women only a single viral genotype was detected early in infection. Infection with multiple viral variants was associated with higher plasma HIV-1 RNA levels and faster CD4 T-cell decline.

Method: Socio-behavioral characteristics, use of hormonal contraceptives, and the presence of sexually transmitted diseases were prospectively assessed at approximately monthly intervals around the time of HIV-1 acquisition in female sex workers in Kenya.

The effect of hormonal contraception on genital tract shedding of HIV-1.

Objective: A previous cross-sectional study reported that hormonal contraception may be associated with increased infectivity in HIV-1 infected women. We conducted a prospective study to determine if cervical shedding of HIV-1 increased after initiating hormonal contraception.

Design: Shedding of HIV-1 DNA (a marker of HIV-1 infected cells) and HIV-1 RNA were measured before and after initiating hormonal contraception.

Vitamin A supplementation and genital shedding of herpes simplex virus among HIV-1-infected women: a randomized clinical trial.

Cross-sectional analyses have associated vitamin A deficiency with genital shedding of herpes simplex virus (HSV) among human immunodeficiency virus type 1 (HIV-1)-infected women. A randomized clinical trial of vitamin A supplementation given daily for 6 weeks was conducted among 376 women in Mombasa, Kenya, who were coinfected with HSV-2 and HIV-1. At follow-up, there was no significant difference in the detection of genital HSV DNA between women receiving vitamin A supplementation and women receiving placebo (40% vs.

Measuring the infectiousness of persons with HIV-1: opportunities for preventing sexual HIV-1 transmission.

Methods to reduce sexual transmission of HIV-1 are urgently needed to slow the global HIV-1 epidemic. These methods should include interventions that minimize susceptibility in uninfected populations at risk, as well as interventions that decrease the infectiousness of HIV-1 infected individuals. Surprisingly few interventions to prevent HIV-1 transmission have been targeted at persons who are already infected, although such interventions could have a significant impact on population-wide HIV-1 spread.

Injectable contraceptive use and genital ulcer disease during the early phase of HIV-1 infection increase plasma virus load in women.

We examined the association between host factors present near the time of human immunodeficiency virus type 1 (HIV-1) acquisition and subsequent virus loads, in a prospective cohort study of women in Mombasa, Kenya. Women were prospectively followed monthly before HIV-1 infection. One hundred sixty-one commercial sex workers who became infected with HIV-1 were followed for a median of 34 months, and 991 plasma samples collected > or =4 months after infection were tested for HIV-1 RNA.

Infection with multiple human immunodeficiency virus type 1 variants is associated with faster disease progression.

Human immunodeficiency virus type 1 (HIV-1)-infected individuals develop a genetically diverse virus population over time, but often only a limited number of viral variants are transmitted from a chronic carrier to a newly infected person. Interestingly, many women but few men are infected by multiple HIV-1 variants from a single partner. To determine whether the complexity of the infecting virus population influences clinical outcome, we examined viral diversity in the HIV-1 envelope sequences present at primary infection in 156 women from Kenya for whom we had follow-up data on viral RNA levels and CD4 T-cell counts.

Early- and intermediate-stage variants of simian immunodeficiency virus replicate efficiently in cells lacking CCR5.

Primate lentiviruses are thought to use the chemokine receptor CCR5 as the major coreceptor for entry into cells. Here we show that some variants of simian immunodeficiency virus (SIV) replicate efficiently in peripheral blood mononuclear cells (PBMCs) lacking a functional CCR5. There were differences in the replication patterns of sequential variants that evolved during SIVMne infection; the late-stage pathogenic variants were unable to replicate in PBMCs lacking CCR5, whereas the early- and intermediate-stage viruses replicated as well in PBMCs lacking CCR5 as they did in cells with wild-type CCR5.

Short-term effect of zidovudine on plasma and genital human immunodeficiency virus type 1 and viral turnover in these compartments.

The effect of zidovudine on plasma and genital human immunodeficiency virus type 1 (HIV-1) was determined in 42 antiretroviral-naive HIV-1-seropositive women in Nairobi. After 7 days of zidovudine treatment, HIV-1 RNA levels decreased by 0.5 to 1.

Comparison of human immunodeficiency virus type 1 viral loads in Kenyan women, men, and infants during primary and early infection.

Steady-state levels of human immunodeficiency virus type 1 (HIV-1) RNA in plasma reached at approximately 4 months postinfection are highly predictive of disease progression. Several studies have investigated viral levels in adults or infants during primary and early infection. However, no studies have directly compared these groups.

Longitudinal analysis of human immunodeficiency virus type 1 RNA in breast milk and of its relationship to infant infection and maternal disease.

Transmission of human immunodeficiency virus type 1 (HIV-1) via breast-feeding can occur throughout lactation. Defining both fluctuation in breast-milk virus level over time and how breast-milk virus correlates with mother-to-child transmission is important for establishing effective interventions. We quantified breast-milk HIV-1 RNA levels in serial samples collected from 275 women for up to 2 years after delivery.