Cellular Immune Responses Induced with Dose-Sparing Intradermal Administration of HIV Vaccine to HIV-Uninfected Volunteers in the ANRS VAC16 Trial Odile Launay 1,2,3 *, Christine Durier 4 , Corinne Desaint 2,3 , Benjamin Silbermann 2,3 , Angela Jackson 5,6 , Gilles Pialoux 7 , Be ´ne ´ dicte Bonnet 8 , Isabelle Poizot-Martin 9 , Gustavo Gonzalez-Canali 10 , Lise Cuzin 11 , Suzanne Figuereido 5,6 , Mathieu Surenaud 5,6 , Nadine Ben Hamouda 5,6 , Hanne Gahery 5,6 , Jeannine Choppin 5,6 , Dominique Salmon 1 , Corinne Gue ´rin 12 , Isabelle Bourgault Villada 5,6,13 , Jean-Ge ´ rard Guillet 5,6 , for the ANRS VAC16 Study Group 1 Universite ´ Paris Descartes, Faculte ´ de Me ´decine, Paris, France, 2 Assistance Publique–Ho ˆ pitaux de Paris, Groupe Hospitalier Cochin-Saint Vincent de Paul, Po ˆle de Me ´decine, CIC de Vaccinologie Cochin-Pasteur, Paris, France, 3 INSERM, CIC de Vaccinologie Cochin-Pasteur, Paris, France, 4 INSERM SC10, Villejuif, France, 5 Institut Cochin, Universite ´ Paris Descartes, CNRS UMR 8104, Paris, France, 6 INSERM, U567, Paris, France, 7 AP–HP, Ho ˆ pital Tenon, Service des Maladies Infectieuses, Paris, France, 8 CHU Ho ˆ tel Dieu, Service des Maladies Infectieuses, Nantes, France, 9 Ho ˆ pital Sainte- Marguerite, Unite ´ CISIH Sud He ´matologie VIH, Marseille, France, 10 Assistance Publique–Ho ˆ pitaux de Paris, Ho ˆ pital Europe ´en Georges Pompidou, Service d’Immunologie Clinique, Paris, France, 11 Ho ˆ pital Purpan, Service des Maladies Infectieuses, Toulouse, France, 12 Assistance Publique– Ho ˆ pitaux de Paris, Ho ˆ pital Cochin, Pharmacie, Paris, France, 13 Assistance Publique–Ho ˆ pitaux de Paris, Ho ˆ pital Ambroise Pare ´, Service de Dermatologie, Boulogne, France Objective. The objective was to compare the safety and cellular immunogenicity of intradermal versus intramuscular immunization with an HIV-lipopeptide candidate vaccine (LIPO-4) in healthy volunteers. Methodology. A randomized, open- label trial with 24 weeks of follow-up was conducted in France at six HIV-vaccine trial sites. Sixty-eight healthy 21– to 55–year- old HIV-uninfected subjects were randomized to receive the LIPO-4 vaccine (four HIV lipopeptides linked to a T-helper– stimulating epitope of tetanus-toxin protein) at weeks 0, 4 and 12, either intradermally (0.1 ml, 100 mg of each peptide) or intramuscularly (0.5 ml, 500 mg of each peptide). Comparative safety of both routes was evaluated. CD8 + T-cell immune responses to HIV epitopes (ELISpot interferon-c assay) and tetanus toxin-specific CD4 + T-cell responses (lymphoproliferation) were assessed at baseline, two weeks after each injection, and at week 24. Results and Conclusion. No severe, serious or life- threatening adverse events were observed. Local pain was significantly more frequent after intramuscular injection, but local inflammatory reactions were more frequent after intradermal immunization. At weeks 2, 6, 14 and 24, the respective cumulative percentages of induced CD8 + T-cell responses to at least one HIV peptide were 9, 33, 39 and 52 (intradermal group) or 14, 20, 26 and 37 (intramuscular group), and induced tetanus toxin-specific CD4 + T-cell responses were 6, 27, 33 and 39 (intradermal), or 9, 46, 54 and 63 (intramuscular). In conclusion, intradermal LIPO-4 immunization was well tolerated, required one-fifth of the intramuscular dose, and induced similar HIV-specific CD8 + T-cell responses. Moreover, the immunization route influenced which antigen-specific T-cells (CD4 + or CD8 + ) were induced. Trial Registration. ClinicalTrials.gov NCT00121121 Citation: Launay O, Durier C, Desaint C, Silbermann B, Jackson A, et al (2007) Cellular Immune Responses Induced with Dose-Sparing Intradermal Administration of HIV Vaccine to HIV-Uninfected Volunteers in the ANRS VAC16 Trial. PLoS ONE 2(8): e725. doi:10.1371/journal.pone.0000725 INTRODUCTION One of the greatest challenges in human immunodeficiency virus/ acquired immunodeficiency syndrome (HIV/AIDS) research is to develop a vaccine that can prevent virus transmission or halt progression to AIDS. An effective HIV vaccine should induce neutralizing antibodies to protect against infection [1]. However, inducing neutralizing antibodies specific to the broad range of HIV subspecies has proven difficult with current candidate vac- cines. Alternatively, numerous clinical and experimental observa- tions have shown that cellular immunity, particularly CD8 + T lymphocytes, plays an important role in controlling HIV infection. These findings led researchers to develop vaccines able to generate HIV-specific cellular responses. Using HIV peptides covalently linked to a lipid tail, an epitope-based candidate vaccine was found to be safe and was able to elicit HIV-specific CD4 + and CD8 + T- cell responses [2]. Lipopeptide formulations successfully induced antiviral cytotoxic T-lymphocyte (CTL) responses in mice [3–7] and monkeys [8–10], and hepatitis B virus (HBV)-specific CTL in humans [11,12]. More recent studies showed that intramuscularly injected HIV lipopeptides were able to trigger HIV-specific T-cell responses in HIV-uninfected volunteers [13–15] and HIV-infected patients [16–17]. The lipid moiety facilitates the peptide’s entry into antigen-presenting dendritic cells, thereby enhancing cell- mediated immune responses [18–20]. Intradermal administration is expected to enhance antigen exposure to antigen-presenting cells, because skin harbors more Academic Editor: James Campbell, University of Maryland School of Medicine, United States of America Received June 19, 2007; Accepted June 20, 2007; Published August 22, 2007 Copyright: ß 2007 Launay et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Funding: The French National Agency for Research on Aids and Viral Hepatitis (ANRS) sponsored the trial. After giving its approval of the protocol, the ANRS was not involved in the collection, analysis or interpretation of the data, writing of the report or the decision to submit the paper for publication. All authors declare that they have no conflicts of interest. Competing Interests: The authors have declared that no competing interests exist. * To whom correspondence should be addressed. E-mail: odile.launay@cch. aphp.fr PLoS ONE | www.plosone.org 1 August 2007 | Issue 8 | e725