A comparison of standard immunogenicity assays for monitoring HIV type 1 gag-specific T cell responses in Ad5 HIV Type 1 gag vaccinated human subjects.
Currently, there are numerous candidate HIV vaccines aimed at inducing T-cell mediated immune responses against HIV. To assess the immunogenicity of such vaccines, a reliable T cell assay must be utilized and typically one of the following assays is chosen for this purpose: bulk culture CTL, MHC I tetramer staining, IFN-gamma ELISPOT, or IFN-gamma intracellular cytokine staining. In this paper we report a comparison of the T cell responses detected by each assay in a large cohort of healthy normal volunteers vaccinated with adenovirus serotype 5 expressing HIV gag. Using stringently validated formats of each of these assays and pools of overlapping HIV gag peptides, we demonstrate that there is a high degree of correlation between all four of the common T cell assays, but inherent differences in the sensitivity of each assay to detect responders. In this study, the ELISPOT assay is shown to have the greatest sensitivity in detecting vaccine responses, while the ICS assay, although less sensitive, has the advantage of providing additional information on the phenotype of the responding cells.
Tobery
Timothy W
TW
Department of Vaccines and Biologics Research, Merck Research Laboratories, West Point, Pennsylvania 19486, USA. timothy_tobery@merck.com
Dubey
Sheri A
SA
Anderson
Kiersten
K
Freed
Daniel C
DC
Cox
Kara S
KS
Lin
Jing
J
Prokop
Michael T
MT
Sykes
Kara J
KJ
Mogg
Robin
R
Mehrotra
Devan V
DV
Fu
Tong-Ming
TM
Casimiro
Danilo R
DR
Shiver
John W
JW
D016915:AIDS Vaccines / Q000276:immunology*; D000256:Adenoviridae; D000293:Adolescent; D000328:Adult; D005260:Female; D015683:Gene Products, gag / Q000276:immunology*; D015488:HIV Antigens / Q000276:immunology; D015658:HIV Infections / Q000517:prevention & control*; D015497:HIV-1; D006801:Humans; D008297:Male; D008875:Middle Aged; D013601:T-Lymphocytes / Q000502:physiology*
D016915:AIDS Vaccines; D015683:Gene Products, gag; D015488:HIV Antigens