Objective: To dissect the biological mechanisms involved in the cellular responses to a candidate vaccine containing 5 HIV peptides coupled to a palmytoil tail (HIV-LIPO-5) in healthy volunteers, by using extensive immunogenicity assessments with different stimulation durations.
Design: Immunogenicity substudy of a randomized phase II prophylactic HIV vaccine trial (ANRS VAC 18).
Methods: HIV-LIPO-5 or placebo was administered at W0, W4, W12 and W24. Peripheral blood mononuclear cells from a subset of participants at W0 and W14 were stimulated with HIV-LIPO-5, Gag peptides contained in the vaccine and control peptides. ELISpot, lymphoproliferation, intracellular cytokine staining (ICS), cytokine multiplex and transcriptomic analyses were performed. Different time points and stimulation conditions were compared, controlling for test multiplicity.
Results: Cultured ELISpot and lymphoproliferation responses were detected at W14. Ex-vivo ICS showed mainly interleukin (IL)-2-producing cells. Secretion of interferon (IFN)-γ, tumour necrosis factor (TNF)-α, IL-5 and IL-13 increased significantly after culture and Gag stimulation at W14 compared to W0. Metallothionein genes were consistently overexpressed after HIV-LIPO-5 stimulation at W0 and W14. At W14, significant probes increased substantially, including IFN-γ, CXCL9, IL2RA, TNFAIP6, CCL3L1 and IL-6. Canonical pathway analyses indicated a role of interferon signalling genes in response to HIV-LIPO-5.
Conclusion: HIV-LIPO-5 vaccination elicited Th1 and Th2 memory precursor responses and a consistent modulation in gene expression. The response profile before vaccination suggests an adjuvant effect of the lipid tail of HIV-LIPO-5. Our combined immunogenicity analyses allowed to identify a specific signature profile of HIV-LIPO-5 and indicate that HIV-LIPO-5 could be further developed as a prime in heterologous prime-boost strategies.
bINSERM, ISPED, Centre INSERM U897-Epidemiologie-Biostatistique, Bordeaux
dUniversity Paris Est Créteil, Faculté de Médecine
eGroupe Henri-Mondor Albert-Chenevier, Immunologie biologique
fMondor Immunology Center, Créteil
gInserm SC10, Villejuif
hUniversity Paris Descartes-Hôpital Cochin, Paris
iGroupe Henri-Mondor Albert-Chenevier, Immunologie clinique, Créteil
jCHU de Bordeaux, Pole de sante publique, Bordeaux, France.
*Laura Richert, Sophie Hue, Rodolphe Thiébaut, and Yves Lévy contributed equally to the writing of this article.
Correspondence to Professor Yves Lévy, MD, PhD, Clinical immunopathology, Hôpital Henri Mondor, INSERM U955, Faculté de Médecine de Créteil, 51, Avenue du Maréchal de Lattre de Tassigny, F-94010 Créteil, France. Tel: +33 1 4981 2455; fax: +33 1 4981 2469; e-mail: firstname.lastname@example.org
Received 5 September, 2012
Revised 21 November, 2012
Accepted 23 January, 2013
Preliminary results of this study were presented at the AIDS Vaccine Conference, 28 September–1 October 2010, Atlanta, Georgia, USA (abstract P14.02), and at the AIDS Vaccine Conference, 12–15 September 2011, Bangkok, Thailand (abstract P14.07).
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