H. Jonuleit et al., Identification and functional characterization of human CD4(+)CD25(+) T cells with regulatory properties isolated from peripheral blood, J EXP MED, 193(11), 2001, pp. 1285-1294
A subpopulation of peripheral human CD4(+)CD25(+) T cells that expresses CD
45RO, histocompatibility leukocyte antigen DR, and intracellular cytotoxic
T lymphocyte-associated antigen (CTLA) 4 does not expand after stimulation
and markedly suppresses the expansion of conventional T cells in a contact-
dependent manner. After activation, CD4(+)CD25(+) T cells express CTLA-4 on
the surface detectable for several weeks. These cells show a G1/G0 cell cy
cle arrest and no production of interleukin (IL)-2, IL-4, or interferon (IF
N)-gamma on either protein or mRNA levels. The anergic state of CD4(+)CD25(
+) T cells is not reversible by the addition of anti-CD28, anti-CTLA-4, ant
i-transforming growth factor beta, or anti-IL-10 antibody. However, the ref
ractory state of CD4(+) CD25(+) T cells was partially reversible by the add
ition of IL-2 or IL-4. These data demonstrate that human blood contains a r
esident T cell population with potent regulatory properties.