Lifespan of human memory T-cells in the absence of T-cell receptor expression.
To evaluate the intrinsic lifespan of human memory T-cells in the absence of T-cell receptor signaling, we used radiation-induced mutant CD4+ T-cells lacking surface expression of TCR/CD3 complex as an in vivo cell marker. We analyzed the long-term kinetics of TCR/CD3 - mutant T-cells among CD4+ CD45RA+ naive and CD4+ CD45RA- memory T-cell fractions in peripheral blood of gynecological cancer patients receiving radiotherapy. Both the proportion and number of these mutant T-cells decayed exponentially with time following radiotherapy. The estimated half-life of mutant memory T-cells was 2 to 3 years and did not differ from that of mutant naive T-cells. These results indicate that the lifespan of mature CD4+ T-cells is limited regardless of their memory or naive phenotype in the absence of TCR/CD3 expression. This finding may suggest that continued T-cell receptor signaling is required for lifetime maintenance of human memory T-cells.
Department of Radiobiology, Radiation Effects Research Foundation, Hiroshima, Japan.
S
S
Umeki
Y
Y
Kusunoki
J B
JB
Cologne
K S
KS
Iwamoto
Y
Y
Hirai
T
T
Seyama
K
K
Ohama
S
S
Kyoizumi
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology* / Q000502:physiology*; D005260:Female; D006801:Humans; D007156:Immunologic Memory / Q000276:immunology*; D008875:Middle Aged; D017260:Receptor-CD3 Complex, Antigen, T-Cell / Q000276:immunology*
D017260:Receptor-CD3 Complex, Antigen, T-Cell