Laser light suicide of proliferating virus-specific CD8+ T cells in an in vivo response.
Virus-specific CD8+ CTL precursor (CTLp) frequencies are a function of rates of clonal expansion and loss, both of which are difficult to assess in vivo. Proliferating T cells incorporate the nucleoside analogue 5-bromo-2'-deoxyuridine (BrdU), making them sensitive to light-induced apoptotic cell death (suicide). Mice were infected with an influenza A virus, then given 50 mg of BrdU 24 h before sampling. Exposure of freshly isolated, CD8-labeled T cells to the laser beam of the flow cytometer resulted in the elimination of > 90% of the responding CTLp. The effect was obvious for the regional lymph node from day 6 to day 12 after priming, indicating continued cycling over a 7-day interval. Thus, as CTLp frequencies remain fairly constant from 7 to 30 days after infection, the persistent increase (> 30x) in numbers must be accompanied by a very substantial loss of virus-specific CD8+ T cells.
Tripp
R A
RA
Department of Immunology, St. Jude Children's Research Hospital, Memphis, TN 38105, USA.
Lahti
J M
JM
Doherty
P C
PC
D000818:Animals; D001973:Bromodeoxyuridine; D018414:CD8-Positive T-Lymphocytes / Q000276:immunology* / Q000821:virology; D016923:Cell Death / Q000276:immunology*; D002455:Cell Division / Q000276:immunology; D005260:Female; D007156:Immunologic Memory; D009980:Influenza A virus / Q000276:immunology*; D007834:Lasers; D008027:Light; D008213:Lymphocyte Activation / Q000276:immunology; D051379:Mice; D008810:Mice, Inbred C57BL
D001973:Bromodeoxyuridine