S. Bertone et al., Transforming growth factor-beta-induced expression of CD94/NKG2A inhibitory receptors in human T lymphocytes, EUR J IMMUN, 29(1), 1999, pp. 23-29
Different HLA class I-specific killer inhibitory receptors (KIR) are expres
sed in vivo by a fraction of activated T cells, predominantly CD8(+), in wh
ich they may inhibit TCR-mediated cell functions. In an attempt to identify
mechanisms leading to KIR expression in T cells, we analyzed the effect of
transforming growth factor-beta (TGF-beta) in T cells responding to bacter
ial superantigens in vitro. We show that TGF-beta induces the expression of
CD94/NKG2A in cells responding to toxic shock syndrome toxin 1 or to other
staphylococcal superantigens. Remarkably, maximal CD94 expression occurred
at (low) TGF-beta concentrations which have no substantial effect on lymph
ocyte proliferation. Maximal CD94 expression occurred when TGF-beta was add
ed shortly after the cells were placed in culture. No expression could be i
nduced in CD94/NKG2A-negative T cell clones. Although both CD4(+) and CD8() expressed CD94, the simultaneous expression of NKG2A was mostly confined
to CD8+ cells. Monoclonal antibody-mediated cross-linking of CD94/NKG2A led
to an impairment of T cell triggering via CD3, as determined in a redirect
ed killing assay using the Fc gamma receptor-positive P815 murine target ce
lls.