The CD8+ granzyme B+ T-cell subset in peripheral blood from healthy individuals contains activated and apoptosis-prone cells.
Granzyme B (GrB) has been implicated in induction of apoptosis in target cells. The presence of GrB in peripheral blood CD8+ T cells from healthy individuals was analysed in immunocytochemical and flow cytometric studies. Furthermore, CD8+ GrB- T cells and CD8+ GrB+ T cells were compared regarding phenotypical characteristics and susceptibility to both spontaneous and Fasmediated apoptosis. GrB was expressed by approximately one-fifth of CD8+ T cells. Compared with the CD8+ GrB- T-cell subset, the CD8+ GrB+ T-cell subset contained cells that were relatively more activated and more prone to spontaneous apoptosis. Culturing of cells with immunoglobulin M (IgM) anti-Fas monoclonal antibody had no additional effect on the number of CD8+ GrB+ T cells undergoing apoptosis. We suggest that the presence of CD8+ GrB+ T cells in peripheral blood from healthy individuals results from immune surveillance or contact with infectious agents, and that spontaneous apoptosis of these cells might serve as a mechanism for their eventual clearance.
Wever
P C
PC
Renal Transplant Unit, Academic Medical Center, Amsterdam, The Netherlands.
Van Der Vliet
H J
HJ
Spaeny
L H
LH
Wolbink
A M
AM
Van Diepen
F N
FN
Froelich
C J
CJ
Hack
C E
CE
ten Berge
I J
IJ
D000911:Antibodies, Monoclonal / Q000494:pharmacology; D017209:Apoptosis / Q000187:drug effects / Q000502:physiology*; D018414:CD8-Positive T-Lymphocytes / Q000201:enzymology* / Q000276:immunology; D002478:Cells, Cultured; D005434:Flow Cytometry; D053804:Granzymes; D006801:Humans; D007150:Immunohistochemistry; D008213:Lymphocyte Activation; D016131:Lymphocyte Subsets / Q000276:immunology*; D012697:Serine Endopeptidases / Q000032:analysis*; D019014:fas Receptor / Q000276:immunology
D000911:Antibodies, Monoclonal; D019014:fas Receptor; C509213:GZMB protein, human; D053804:Granzymes; D012697:Serine Endopeptidases