Cellular immune responses to yellow fever vaccine virus: a comprehensive functional characterization of
T-cell specific responses in vaccinees.

Status: Study finished
Number of volunteers: 50
Number of visits: 5

In the Framework of an HIV vaccine development, more knowledge on correlates of protection of current successful viral vaccines is needed.

Yellow fever immunization with vaccine strain YF-17D is a classic example of a safe and efficient live attenuated vaccine. A single dose induces a durable protection due to neutralizing antibodies and YF-specific T cell responses.

Antibody response to YF-17D virus has been well characterized and shown to be a major component of the effectiveness of the vaccine, however, cell-mediated immunity induced by 17D virus is still poorly understood. Only recently, microarray technology has been successfully used to study cellular responses to YF-17D virus, leading to the identification of genes implicated in different immune pathways.

This study’s purpose is to contribute in understanding better the complexity of the T-cell response induced by YF-17D immunization.

The recruitment for this study took place at the Travel Medicine Consultation from the Policlinique Médicale Universitaire (PMU) at Lausanne and consisted of healthy adult travelers in need of yellow fever vaccination for their trip to South American or African countries. Following this first visit, 4 follow-up visits are performed at the Vaccine and Immunotherapy Center (VIC) in a length of  15 months.

Status: Study finished
Number of volunteers: 40 healthy volunteers (25 at CHUV, 15 at the St Mary's Hospital, London, UK)
Length of study: February 2005 – March 2006

A phase I trial to assess the safety and immunogenicity of two experimental HIV vaccines when administered alone (NYVAC-C) or in combination (DNA-C + NYVAC-C) in healthy volunteers at low risk of HIV infection.

The trial enrolled 40 healthy volunteers, 25 at the CHUV, in Lausanne, and 15 at Saint Mary’s Hospital from the Imperial College in London. The EuroVacc Foundation was the sponsor of this study.

Group 1

N = 20

DNA-C

DNA-C

NYVAC-C

NYVAC-C

Group 2

N = 20

NYVAC-C

Results: Here is an article about the study results published by the VIC staff in the Journal of Experimental Medicine, on January 15^th 2008: <An HIV-1 clade C DNA prime, NYVAC boost vaccine regimen induces reliable, polyfunctional, and long-lasting T cell responses. Alexandre Harari et al.

Status: Study finished
Number of volunteers: 147 healthy volunteers (38 at CHUV)
Length of study: June 2007 - October 2009

A phase I/II trial to compare the immunogenicity and safety of 3 DNA-C prime followed by 1 NYVAC-C boost to 2 DNA-C prime followed by 2 NYVAC-C boost in healthy volunteers, at low risk of HIV infection.

These vaccines are based on an HIV subtype, which is prevalent in China, India and sub-Saharan Africa, and constitutes more than 50% of the new HIV infections worldwide. The recruitment involves 147 volunteers from 4 countries (Germany, Switzerland, UK and several sites in France). The EuroVacc Foundation acts as the sponsor for the sites in Germany, Switzerland and UK, and the Agence Nationale de Recherche sur le Sida (ANRS) acts as sponsor for the French sites, and Legal Representative of the EuroVacc Foundation in the European Union member states.

Group 1

N = 70

DNA-C

DNA-C

DNA-C

NYVAC-C

Group 2

N = 70

DNA-C

DNA-C

NYVAC-C

Status: Study finished
Number of volunteers: 111 healthy volunteers (26 at CHUV)
Length of study: November 2003 – September 2005

A randomized, placebo-controlled, dosage-escalating phase 1 study, double-blinded with respect to assignment to either vaccine or placebo, to evaluate the safety and immunogenicity of a modified vaccinia virus ankara vaccine containing the clade A HIV-1 gag gene, (MVA.HIVA) vaccine administered by three different routes and at three different dosage levels in HIV-uninfected, healthy volunteers.

For this study, 111 volunteers were enrolled on 5 sites (two in South Africa, one in the UK, one in the Netherlands and one in Switzerland). The VIC enrolled 26 volunteers. The study was organized by the International Aids Vaccine Initiative (IAVI), which is an international non-profit organization, whose mission is to develop a preventive vaccine, safe and immunogenic against HIV.

Resullts: The first results from previous studies involving the same vaccine products (IAVI 006 and IAVI 009) showed very weak immune responses. Thus the decision was taken to discontinue administering small and medium doses of the same vaccine product. In the IAVI 010 protocol, bigger doses of the vaccine product were administered. This study had already begun prior to IAVI 011, and it was decided to evaluate the immunogenicity of the stronger dose only in the first study. As a result, IAVI 011 was discontinued.

Status: Study finished
Number of volunteers: 24 healthy volunteers (12 at CHUV, 12 at the St Mary Hospital, London UK)
Length of study: August 2003 – August 2004

EuroVacc 01 was a phase I study to evaluate the safety of the NYVAC-C vaccine in healthy volunteers at low risk of HIV infection.

The NYVAC-C vaccine was developed by the European consortium EuroVacc, financed by the 5^th framework program of the European Union. 24 volunteers were enrolled, 12 in London at Saint Mary’s Hospital, and 12 at the VIC. The main goal of the study was to evaluate the safety and the immunogenicity of the NYVAC-C.

Status: Study finished
Number of volunteers: 10 HIV positive patients
Length of study: May 2006 – June 2007

The TheraVac study program for the “Evaluation of a new therapeutic vaccination strategy for HIV infection” is funded by the European Union and involves several research laboratories. The working hypothesis of this program is that a combination of a new and potent HIV vaccine with HAART should restore a protective immune control of HIV that would allow limiting drug toxicity by prolonging the time without antiretroviral therapy. The first step of this clinical program consisted of 2 single center phase 1 clinical trial with identical design to evaluate the safety of this new therapeutic strategy, that combines HAART with a new HIV recombinant poxvirus vaccine (NYVAC-B for TheraVac 01 performed at the CHUV and MVA-B for TheraVac 02 performed in the Netherlands).

TheraVac 01 took place at the Vaccine and Immunotherapy Center (VIC) and enrolled 10 patients, infected by HIV-B, and treated successfully with HAART since at least 6 months.

The study was an open-label phase I study to evaluate the safety of the HIV-1 vaccine NYVAC-B.

TheraVac 02 took place in The Netherlands, at the Academic Medical Center of Amsterdam.

Study on the impact of a soluble molecule agonist CD40 on the quality of the immune T response with a view to elaborate a vaccination strategy against HIV.

Status: Study finished
Number of volunteers: 30
Number of visits: 1 or 2

A majority of healthy adults (80-90%) carry viruses such as the Cytomegalovirus (CMV), the Epstein-Barr Virus (EBV) and the Herpes Simplex Virus (HSV). Some cells from the immune system, of which the T memory cells, have developed to some parts of these viruses, called antigens, a response sufficiently strong to be detected directly ex vivo. Also, many individuals’ memory T cells have developed this same type of responses against the tetanus vaccination. T cells coming from subjects with such a response are an ideal model for the study of the capacity of new molecules to enhance the immune T response. The T cells are isolated from the white blood cells. The response of these cells against viral antigens derived from CMV, EBV and HSV, and against the tetanos toxin are assessed with or without the presence of the sCD40L agonist soluble of CD40.

Status: Study finished
Number of volunteers: 50
Number of visits: 1 or 2
 

Standardization and Validation of immunologic assays, and evaluation of the specific T cells immune response to different viruses.

The goal of this study is to carry out a systematic study of the immune response against viruses that are very widespread and generally well-controlled like the CMV (Cyto MegaloVirus), and the EBV (Epstein Barr Virus), in order to better understand which parameters are involved in the effective control of these viruses and to identify the defective parameters of the immune response against HIV.