Mark S. De SouzaSilvia Ratto-KimWeerawan ChuenaromAlexandra SchuetzSomsak ChantakulkijBessara NuntapinitAnais Valencia-MicoltaDoris ThelianSorachai NitayaphanPunnee PitisuttithumRobert M. ParisJaranit KaewkungwalNelson L. MichaelSupachai Rerks-NgarmBonnie MathiesonMary MarovichJeffrey R. CurrierJerome H. KimSupamit ChunsuttiwatNakorn PremsriChawetsan NamwatPrayura KunasolPrasert ThongcharoenChirasak KhamboonruangValai BussaratidWirach Maek-a-nantawatJittima DhitavatPravan SuntharasamaiSwangjai PungpakSiriwan VanijanontaJaranit KaewkunwalAmnat KhamsiriwatcharaPawinee JarujareetChirapa EasmilaSuchana TabprasitViseth NgauyRobert ParisMichael BenensonPatricia MorganArthur BrownMark De SouzaRapee TrichavarojNusara ThaitawatKanyasiri KongnonkokBoot KeawboonYuwadee Phuang-NgernSusan MasonSanjay GurunathanJim TartagliaJohn G. McNeilRobin HarknessClaude MericLynn BaglyosRaphaelle El HabibDon FrancisCarter LeeElizabeth AdamsMerlin L. RobbMark MilazzoAmy BolenBeryl WessnerJeffrey CurrierDeborah L. BirxDon StableinTerry GermansonLen DallyJean Louis ExclerJeffrey BerenbergArmed Forces Research Institute of Medical Sciences, ThailandWalter Reed Army Institute of ResearchMahidol UniversityThailand Ministry of Public HealthNational Institutes of Health, BethesdaSanofi PasteurSanofi PasteurGlobal Solutions in Infectious DiseasesNational Institute of Allergy and Infectious DiseasesU.S. Army Medical Research and Materiel CommandCenters for Disease Control and PreventionThe EMMES CorporationInternational AIDS Vaccine InitiativeTripler Regional Med Center2018-06-112018-06-112012-05-15Journal of Immunology. Vol.188, No.10 (2012), 5166-517615506606002217672-s2.0-84861173075https://repository.li.mahidol.ac.th/handle/20.500.14594/14321The Thai HIV phase III prime/boost vaccine trial (RV144) using ALVAC-HIV (vCP1521) and AIDSVAX B/E was, to our knowledge, the first to demonstrate acquisition efficacy. Vaccine-induced, cell-mediated immune responses were assessed. T cell epitope mapping studies using IFN-γ ELISPOT was performed on PBMCs from HIV-1-uninfected vaccine (n = 61) and placebo (n = 10) recipients using HIV-1 Env peptides. Positive responses were measured in 25 (41%) vaccinees and were predominantly CD4 + T cell-mediated. Responses were targeted within the HIV Env region, with 15 of 25 (60%) of vaccinees recognizing peptides derived from the V2 region of HIV-1 Env, which includes the α 4 β 7 integrin binding site. Intracellular cytokine staining confirmed that Env responses predominated (19 of 30; 63% of vaccine recipients) and were mediated by polyfunctional effector memory CD4 + T cells, with the majority of responders producing both IL-2 and IFN-γ (12 of 19; 63%). HIV Env Ab titers were higher in subjects with IL-2 compared with those without IL-2-secreting HIV Env-specific effector memory T cells. Proliferation assays revealed that HIV Ag-specific T cells were CD4 + , with the majority (80%) expressing CD107a. HIV-specific T cell lines obtained from vaccine recipients confirmed V2 specificity, polyfunctionality, and functional cytolytic capacity. Although the RV144 T cell responses were modest in frequency compared with humoral immune responses, the CD4 + T cell response was directed to HIV-1 Env and more particularly the V2 region.Mahidol UniversityImmunology and MicrobiologyArticleSCOPUS10.4049/jimmunol.1102756