Early Immune Responses to Vaccination - A Substudy to HVTN 205
Condition: HIV Infections
MeSH terms: HIV Infections
Study type: Observational

Summary: 
      HVTN 908 is a sub study of the HIV vaccine trial, HVTN 205. The purpose of this sub study is
      to better understand how a person's immune system responds to vaccines, particularly HIV
      vaccines. More specifically, researchers will determine whether early responses in the immune
      system help predict strong and long-lasting immunity.
    

Detailed description: 
      Some of the first HIV vaccines were designed to trigger neutralizing antibody responses as a
      way to prevent HIV infection. Unfortunately, the first versions of these vaccines were not
      able to achieve their desired response. An alternative strategy to the antibody approach is
      the stimulation of HIV-specific CD8 T-lymphocyte (CTL) responses. CTL responses were
      previously demonstrated to play an important role in the control of simian immunodeficiency
      virus (SIV), the HIV equivalent studied in rhesus macaque monkeys. Additionally, other
      studies suggest CTLs play an important role in viral control during chronic infection. Based
      on this information, several groups have shifted their focus to the development of CTL-based
      vaccines, some of which have entered advanced clinical trials.

      A DNA/rMVA vaccine strategy is structured to bring about both T cell and antibody responses.
      The primary vaccination is DNA based and will express only HIV proteins as a way to produce
      an HIV-focused immune response. A secondary, rMVA boost vaccination, which expresses both HIV
      and MVA proteins will ideally amplify the focused response of the initial vaccination. The
      DNA and rMVA are physically two different vaccinations given at separate times but together
      they make up one preventive regimen. Both vaccine components express non-infectious
      virus-like particles.

      The main study, HVTN 205 will evaluate the safety of and immune response to a two vaccine
      regimen in healthy, HIV-uninfected adults who never received an HIV preventive vaccine
      before. HVTN 205 will include two parts, Part A, in which the two vaccine regimen is compared
      to a placebo, and Part B, in which the two vaccine regimen will be compared to both a placebo
      and a single vaccine regimen with the rMVA vaccine.

      HVTN 908 is a sub study of HVTN 205, and will explore the innate immune response to candidate
      HIV vaccines. In particular, researchers will study whether early immune response following
      vaccination can predict strong and long-lasting immunity. They will also study whether
      varying types of vaccines promote different immune responses soon after vaccination.

      Only participants enrolled in HVTN 205 are eligible for HVTN 908. Approximately 50
      participants will be recruited for the duration of 12 months per participant. The study will
      last for a total of 2 years, including enrollment, follow-up, and analysis. Potential
      participants of the sub study will undergo a screening visit before eligibility can be
      determined. Screening may involve a physical exam, health history, and blood tests.

      There will be some additional visits for participants of HVTN 908 that are not included in
      the main study. Some main study visits may also take extra time for participants enrolled in
      the sub study. Blood samples will be taken at study visits. These samples are taken in
      addition to those for the main study.
    

Intervention name(s): JS7 DNA vaccine; MVA/HIV62 vaccine
Intervention type(s): Biological; Biological
Intervention MeSH terms: Vaccines
Observational model: Case-Only
Time perspective: Prospective
Sampling method: Non-Probability Sample
Study population: 
        Participants enrolled in HVTN 205
      
Biospecimen description: 
      Blood samples 30 - 90 mL per visit
    
Keywords: HIV Seronegativity; HIV Preventive Vaccine