Integration of apoptosis and telomere erosion in virus-specific CD8+ T cells from blood and tonsils during primary infection.
Human-virus-specific CD8+ T cells that are found during primary infection have been studied almost exclusively in the peripheral blood, and it is unclear whether these cells are regulated in the same way as those in secondary lymphoid tissue. We investigated, therefore, the control of apoptosis and telomere erosion of Epstein-Barr virus (EBV)-specific CD8+ T cells found in the blood and tonsils of the same patients during acute infectious mononucleosis (AIM). Although the clonal composition of CD8+ T cells as determined by heteroduplex analysis was similar in both compartments, there was greater CD28 expression in the tonsil population, indicating that they were less differentiated. EBV-specific CD8+ T cells in both tissue types were extremely susceptible to apoptosis related to low Bcl-2 expression and were dependent on exogenous cytokines such as interleukin-2 (IL-2), IL-15, and interferon-alpha/beta (IFN-alpha/beta) for survival. In both compartments, however, these cells maintained their telomere lengths through telomerase induction. Thus, apoptosis-prone EBV-specific CD8+ T cells found during acute infection have to be rescued from death to persist as a memory population. However, signals that induce telomerase ensure that the rescued cells retain their replicative capacity. Significantly, these processes operate identically in cells found in blood and secondary lymphoid tissue.
Soares
Maria Vieira D
MV
Department Immunology and Molecular Pathology, Windeyer Institute for Medical Sciences, Royal Free and University College Medical School, London, United Kingdom.
Plunkett
Fiona J
FJ
Verbeke
Caroline S
CS
Cook
Joanne E
JE
Faint
Jeff M
JM
Belaramani
Lavina L
LL
Fletcher
Jean M
JM
Hammerschmitt
Nicholas
N
Rustin
Malcolm
M
Bergler
Wolfgang
W
Beverley
Peter C L
PC
Salmon
Mike
M
Akbar
Arne N
AN
D000208:Acute Disease; D017209:Apoptosis; D018106:CD28 Antigens / Q000378:metabolism; D018414:CD8-Positive T-Lymphocytes / Q000201:enzymology / Q000276:immunology* / Q000473:pathology*; D016022:Case-Control Studies; D002454:Cell Differentiation; D002455:Cell Division; D016207:Cytokines / Q000378:metabolism; D004854:Herpesvirus 4, Human / Q000276:immunology; D006801:Humans; D007156:Immunologic Memory; D007244:Infectious Mononucleosis / Q000201:enzymology / Q000276:immunology* / Q000473:pathology*; D014066:Palatine Tonsil / Q000276:immunology / Q000473:pathology; D019098:Telomerase / Q000378:metabolism*
D018106:CD28 Antigens; D016207:Cytokines; D019098:Telomerase