This study will test the safety and immune response to an experimental HIV vaccine, LIPO-5, in healthy volunteers. LIPO-5 contains 5 lipopeptides from gag, nef and pol corresponding to more than 50 epitopes. LIPO-5 has been shown to be immunogenic and well tolerated in a first phase I trial in non-HIV infected volunteers. Lower doses of each peptide could have a similar immunogenicity.

The aims of HIV lipopeptide vaccination approach are to improve cell mediated immune responses in order to obtain strong, long lasting and polyepitopic responses and to focus these responses on highly conserved and immunogenic epitopes.

Lipopeptides are chemically synthetized peptides, bearing HIV epitopes, covalently bound to a fatty acid moiety, a monopalmtoyl chain in this case. This lipid chain produces internalization of the lipopeptide into the cytoplasm of the antigen presenting cells. Combinations of several lipopeptides containing sequences from different HIV proteins are used in vaccination trials in order to increase polyepitopic responses. Lipopeptides have been synthetized by the French National Agency for Research on AIDS and Viral Hepatitis (ANRS) preventive program by the group of Helen Gras following a long and meticulous work of epitope screening performed by the team of Jean-Gérard Guillet at the Cochin Institute in Paris. The epitopes were selected on the basis of their strong affinity for HLA class I molecule, on their ability to form a stable complex with these molecules, and on the capacity of these epitopes to be recognized by T cells. The selected peptides are those containing the richest array of epitopes and those most frequently recognized by HIV infected patients. Each peptide has a length of 23 to 32 amino acids (AA).

Different types of lipopeptides constructs have been tested in humans. Among these constructs, LIPO-5 contains 5 lipopeptides from gag, nef and pol corresponding to more than 50 epitopes. LIPO-5 has been shown to be immunogenic and well tolerated in a first phase I trial in non-HIV infected volunteers. Lower doses of each peptide could have a similar immunogenicity.

Inclusion Criteria:

• Healthy volunteers selected by ANRS (French National Agency for Research on AIDS and Viral Hepatitis)
• For woman of child-bearing age: use of effective contraception
• Ability to sign informed consent
• Beneficiary subjects of social security regimen-- Hepatitis B, hepatitis C, HIV, HTLV1 infection and syphilis negative
• Hemoglobin over 12.5 g/dl for women and over 13.5 g/dl for men

Exclusion Criteria:

• Previous participation in an HIV clinical trial
• Volunteers with risk to contract HIV infection during the trial
• Previous vaccination in the last month, and volunteers requiring vaccination during the trial
• Gift of blood in the last 2 months
• Eczema, urticaria
• Medical history of food allergy, Lyell or Stevens Johnson syndrome and aggravated asthma
• Previous (last 6 months) or ongoing administration of immunological treatment, chemotherapy, radiotherapy or corticosteroid
• Medical history of autoimmune disease
• Clinical or biological aftermath of previous disease
• Medical history of uveitis
• Transfusion in the last 6 months