Sexually Transmitted Infections
Effect of Lactobacillus on Genital HIV-1 RNA and DNA Shedding in Women
Jane E Hitti, MD, MPH
Genital HIV-1 viral load is a major predictor of sexual and perinatal HIV transmission, and strategies to decrease HIV-1 shedding, while promoting vaginal health, are urgently needed. We hypothesize that hydrogen peroxide-producing lactobacillus (L. crispatus and L. jensenii), key components of the normal vaginal flora, decrease genital HIV-1 RNA and DNA shedding among HIV-1-infected women by direct viral inhibition and also by relative suppression of potentially pathogenic vaginal bacteria associated with bacterial vaginosis (BV). We propose to evaluate this hypothesis using archived cervicovaginal lavage (CVL) and cervical cytobrush samples from parallel cohorts of HIV-1-infected women in the United States and Kenya. Specifically, we will:
- Examine the effect over time of L. crispatus, L. jensenii, and L. iners presence and concentrations on HIV-1 RNA load in CVL, as well as the effect of these organisms on pro-inflammatory cytokines and other BV-associated flora. We anticipate that acquisition and/or higher concentrations of L. crispatus and L. jensenii (but not L. iners) will result in a signifi cant decrease in CVL HIV-1 RNA accounting for other factors such as plasma viral load and antiretroviral therapy, and that this protective effect may be mediated by down-regulation of pro-inflammatory cytokines and/or suppression of BV-associated bacteria.
- Assess the longitudinal effect of vaginal Lactobacillus species, other BV-associated organisms, and pro-inflammatory cytokines on endocervical HIV-1 DNA quantitation, as well as endocervical HIV-1 RNA. We hypothesize that the protective effect of L. crispatus and L. jensenii will extend to the endocervix and will include a decrease in proliferation of HIV-1-infected cells as well as viral replication.
Taken together, these aims will add to our understanding of the mechanisms by which hydrogen peroxide-producing lactobacillus modulates HIV-1 in the female genital tract, and may add rationale for further evaluation of probiotics as a potential secondary HIV-1 prevention strategy.
Funding Source: NIH
Contact: Jane E Hitti, MD, MPH, (206) 543-9867
UW IMPAACT Clinical Trial Unit
Jane E Hitti, MD, MPH
The Seattle Children's Hospital/University of Washington International Maternal, Pediatric and Adolescent AIDS Clinical Trials (IMPAACT) site is the only perinatal/pediatric clinical trials unit in the Pacific Northwest, and offers treatment trials to all HIV-infected pregnant women and HIV-exposed or infected children in the region. These funds support the screening, enrollment, and follow-up of HIV-infected pregnant and postpartum women and their HIV-exposed infants into clinical trials in the IMPAACT network, with attention to providing excellent quality of data collection and timeliness.
Funding Source: Seattle Children's Hospital/Research
Contact: Jane E Hitti, MD, MPH, (206) 543-9867
HIV-Specific Antibodies in Vaginal Swabs from HIV-Uninfected HPTN-035 Participants
Florian Hladik, MD, PhD
HPTN 035 is a phase II/IIb safety and effectiveness study of the vaginal microbicides buffer gel and 0.5% PRO 2000/5 gel for the prevention of HIV infection in women. This study will address the hypothesis that women sexually exposed to HIV-1 (while using a topical microbicide) and who remain uninfected develop a compartmentalized humoral immune response.
Secretions extracted from vaginal swabs will be tested for HIV-specific IgG and IgA antibodies by luminex technology. These assays will be performed in collaboration with Dr. Georgia Tomaras (Duke University, NC). We will initially screen swabs from 100 HIV-uninfected and 10 HIV-infected women (positive controls). The luminex technology enables multiplexed quantification of both IgG and IgA antibodies directed at HIV-1 clade C consensus sequence antigens, including Env gp120, Env gp41, Gag and accessory proteins. Based on the initial results with 100 HIV-uninfected women, we will continue to screen a larger cohort of HPTN 035 participants.
Funding Source: Magee-Womens Research Institute and Foundation
Contact: Florian Hladik, MD, PhD, (206) 221-2740
Comparison of Immune Cells in the Cervix Between Women With and Without Detectable Genital HIV-1
Caroline M Mitchell, MD, MPH
Over 15 million women are infected with HIV-1 worldwide, primarily through heterosexual intercourse. Transmission of HIV-1 to the male sexual partners for infants at the time of delivery occurs through shedding of HIV-1 in the cervicovaginal secretions. Some HIV-1 infected women have high levels of vaginal HIV-1 shedding, while others have no detectable virus. Epidemiologic studies suggest that while plasma viral load is an important predictor of genital shedding of HIV-1, genital tract infections and local inflammation may also promote viral shedding. However, the mechanism for this association has not been described, and interventions to treat infections have not always decreased genital shedding of HIV-1.
We hypothesize that trafficking of infected cell to the genital tract and proliferation of HIV-1 infected CD4+ T cells in the genital mucosa are an important determination of HIV-1 genital tract shedding. Our studies have shown that genital tract virus is composed of many identical genetic sequences (i.e., monophyletic), which suggests proliferation of infected cells that are either resistant cells or traffic to the genital tract. In this study we aim to test out hypothesis in two ways:
- To compare the number of CD4+ T cells in cervical biopsy sections between women with and without genital HIV-1 shedding, and
- To compare the number of CD4+ T cells in cervical biopsy sections between women with and without monophyletic viral sequences
Funding Source: Puget Sound Partners for Global Health (PSPGH)/Fred Hutchinson Cancer Research Center (FHCRC)
Contact: Caroline Mitchell, MD, MPH, (206) 744-3667
A Randomized, International, Double-Blind, Controlled with GARDASIL TM, Dose-Ranging, Tolerability, Immunogenicity, and Efficacy Study of a Second Generation Human Papillomavirus L1 Virus-Like Particle Vaccine Administered to 16 to 26 Year Old Women
Constance Mao, MD
Contact: Constance Mao, MD, (206) 744-6291
The Female Genital Innate Immune Response to Vaginal Microbiota (K08)
Caroline Mitchell, MD
Mentor: David N Fredricks, MD
Bacterial vaginosis (BV) is a vaginal syndrome characterized by an overgrowth of anaerobic vaginal bacteria, and is associated with several adverse clinical outcomes, including pelvic inflammatory disease, preterm birth and increased risk of HIV-1 acquisition. The individual bacterial species differ between individuals, as do the clinical symptoms, the incidence of serious sequelae, and patterns of cytokine response. We hypothesize that clinical differences result from the interactions between individual species and host immune responses. We plan to test the following hypotheses:
- that some bacterial species downregulate the innate host response, allowing high levels of colonization by decreasing levels of vaginal cytokines and/or production of antimicrobial peptides(beta-defensins, cathelicidin, secretory leukocyte protease inhibitor[SLPI], lactoferrin);
- that some individuals are more vulnerable to colonization due to low baseline levels of those antimicrobial peptides;
- that Lactobacillus species and BV-associated pathogens activate the innate immune response differently via pattern-recognition receptors like TLR-2; and
- that some bacterial species are more likely to colonize the upper genital tract due to the presence of virulence factors or mechanisms for subverting the host immune response.
We will characterize prospectively collected daily vaginal swabs from 30 women for levels of individual bacterial species using qPCR for the 16S rRNA gene, and correlate these with the temporal response in levels of cytokines and antimicrobial peptides (Aim 1). Responses in vaginal epithelial cell culture will be used to determine whether lactobacilli and BV-associated microbes activate toll-like receptors differently resulting in different cytokine profiles, and whether TLR-2 activation is associated with higher levels of antimicrobial peptides (Aim 2). Endometrial samples collected at hysterectomy will be characterized by broad range 16S rRNA PCR and pyrosequencing to detect upper genital tract colonization and define the microbiota in comparison to the vaginal microbiota in the same women. In addition, levels of cervical cytokines and defense molecules will be measured to assess their relationship with upper tract colonization (Aim 3). The PI for this application, Caroline Mitchell, MD is an OB/Gyn whose goal is to understand how the female genital tract defends against bacterial pathogens, with the ultimate endpoint of developing better therapeutic and preventive interventions. Her mentor, Dr. David Fredricks, is a nationally recognized investigator known for using advanced molecular techniques to better characterize the vaginal microbiota, and has recently been recognized for excellence in mentoring. The University of Washington is the top public university for research funding, with an internationally-renowned Infectious Diseases program and a long history of studies on BV. The scientific advisory committee has expertise in immunologic techniques, clinical trials and data analysis.
Funding Source: NIH
Contact: Caroline Mitchell, MD
Safety and Efficacy of Chlamydia Vaccine Candidates
Dorothy Patton, PhD
Funding Source: Wyeth Pharmaceuticals
Contact: Dorothy L Patton, PhD, (206) 543-5554