Comprehensive epitope analysis of human immunodeficiency virus type 1 (HIV-1)-specific T-cell responses directed against the entire expressed HIV-1 genome demonstrate broadly directed responses, but no correlation to viral load.
Cellular immune responses play a critical role in the control of human immunodeficiency virus type 1 (HIV-1); however, the breadth of these responses at the single-epitope level has not been comprehensively assessed. We therefore screened peripheral blood mononuclear cells (PBMC) from 57 individuals at different stages of HIV-1 infection for virus-specific T-cell responses using a matrix of 504 overlapping peptides spanning all expressed HIV-1 proteins in a gamma interferon-enzyme-linked immunospot (Elispot) assay. HIV-1-specific T-cell responses were detectable in all study subjects, with a median of 14 individual epitopic regions targeted per person (range, 2 to 42), and all 14 HIV-1 protein subunits were recognized. HIV-1 p24-Gag and Nef contained the highest epitope density and were also the most frequently recognized HIV-1 proteins. The total magnitude of the HIV-1-specific response ranged from 280 to 25,860 spot-forming cells (SFC)/10(6) PBMC (median, 4,245) among all study participants. However, the number of epitopic regions targeted, the protein subunits recognized, and the total magnitude of HIV-1-specific responses varied significantly among the tested individuals, with the strongest and broadest responses detectable in individuals with untreated chronic HIV-1 infection. Neither the breadth nor the magnitude of the total HIV-1-specific CD8+-T-cell responses correlated with plasma viral load. We conclude that a peptide matrix-based Elispot assay allows for rapid, sensitive, specific, and efficient assessment of cellular immune responses directed against the entire expressed HIV-1 genome. These data also suggest that the impact of T-cell responses on control of viral replication cannot be explained by the mere quantification of the magnitude and breadth of the CD8+-T-cell response, even if a comprehensive pan-genome screening approach is applied.
Addo
M M
MM
Partners AIDS Research Center, Massachusetts General Hospital and Harvard Medical School. Fenway Community Health Center. Lemuel Shattuck Hospital, Boston, Massachusetts 02129, USA.
Yu
X G
XG
Rathod
A
A
Cohen
D
D
Eldridge
R L
RL
Strick
D
D
Johnston
M N
MN
Corcoran
C
C
Wurcel
A G
AG
Fitzpatrick
C A
CA
Feeney
M E
ME
Rodriguez
W R
WR
Basgoz
N
N
Draenert
R
R
Stone
David R
DR
Brander
C
C
Goulder
P J R
PJ
Rosenberg
E S
ES
Altfeld
M
M
Walker
B D
BD
D000163:Acquired Immunodeficiency Syndrome / Q000276:immunology* / Q000821:virology; D000595:Amino Acid Sequence; D018984:Epitopes, T-Lymphocyte; D005260:Female; D015693:Gene Products, nef / Q000276:immunology; D016679:Genome, Viral; D016655:HIV Core Protein p24 / Q000276:immunology; D015497:HIV-1 / Q000276:immunology*; D006801:Humans; D007371:Interferon-gamma / Q000096:biosynthesis; D008297:Male; D008969:Molecular Sequence Data; D010446:Peptide Fragments / Q000276:immunology; D013601:T-Lymphocytes / Q000276:immunology*; D019562:Viral Load; D054311:nef Gene Products, Human Immunodeficiency Virus
D018984:Epitopes, T-Lymphocyte; D015693:Gene Products, nef; D016655:HIV Core Protein p24; D010446:Peptide Fragments; D054311:nef Gene Products, Human Immunodeficiency Virus; D007371:Interferon-gamma