Detection of high frequencies of HIV-1 cross-subtype reactive CD8 T lymphocytes in the peripheral blood of HIV-1-infected Kenyans.
OBJECTIVE
To quantitate rapidly the frequency of HIV-1 subtype-specific and broadly HIV-1 cross-subtype-reactive CD8 T cells in the peripheral blood of HIV-1-infected individuals from a geographical region of multiple subtype endemicity.


METHODS
Autologous B-lymphoblastoid cell lines infected with recombinant vaccinia-viruses expressing gag, env and nef gene products from HIV-1 subtypes A-H were used as antigen-presenting cells to stimulate CD8 T cells from cryopreserved peripheral blood mononuclear cells. Cross-subtype and subtype-specific CD8 cell responses were assessed by flow cytometry for the upregulation of IFN-gamma gene expression in specifically activated CD8 T cells.


RESULTS
Strikingly high frequencies of circulating CD8 T cells (up to 11.3% of peripheral CD8 T cells) with specificity for HIV-1 were detectable using this methodology. Both subtype-specific and broadly cross-subtype-reactive CD8 T cells were detected as assessed by IFN-gamma production after stimulation. The pattern of cross-subtype reactivity appeared to be random when the results were assessed as a population, but analysis of the full-length sequence of the infecting virus for each individual showed some skewing of the CD8 cell response towards the infecting subtype.


CONCLUSIONS
High frequencies of HIV-1 cross-subtype-reactive peripheral CD8 T cells can be detected in individuals from a multiple subtype endemic region, providing an incentive for vaccine advancement in such locations. The future assessment of the subtype specificity of cellular immune responses requires full-length sequencing of the infecting virus in conjunction with a comprehensive analysis of phenotypic and functional parameters.
Currier
Jeffrey R
JR
US Military HIV Research Program, Suite 200, 13 Taft Court, Rockville, MD 20850, USA. jcurrier@hivresearch.org
Dowling
William E
WE
Wasunna
K Monique
KM
Alam
Uzma
U
Mason
Carl J
CJ
Robb
Merlin L
ML
Carr
Jean K
JK
McCutchan
Francine E
FE
Birx
Deborah L
DL
Cox
Josephine H
JH
D018414:CD8-Positive T-Lymphocytes / Q000276:immunology*; D002460:Cell Line; D003429:Cross Reactions / Q000276:immunology; D005434:Flow Cytometry / Q000379:methods; D015967:Gene Expression Regulation, Viral / Q000235:genetics / Q000276:immunology; D015686:Gene Products, env / Q000276:immunology; D015683:Gene Products, gag / Q000276:immunology; D015693:Gene Products, nef / Q000276:immunology; D015658:HIV Infections / Q000097:blood / Q000453:epidemiology / Q000276:immunology*; D015497:HIV-1 / Q000235:genetics / Q000276:immunology*; D006801:Humans; D007371:Interferon-gamma / Q000096:biosynthesis; D007630:Kenya / Q000453:epidemiology; D016176:T-Lymphocyte Subsets / Q000276:immunology; D015854:Up-Regulation / Q000235:genetics / Q000276:immunology; D054311:nef Gene Products, Human Immunodeficiency Virus
D015686:Gene Products, env; D015683:Gene Products, gag; D015693:Gene Products, nef; D054311:nef Gene Products, Human Immunodeficiency Virus; D007371:Interferon-gamma