LIL-Stat, which specifically recognizes the LILRE sequence, is not constitutively activated in normal lymphocytes.

A, LILRE was used as a radiolabeled probe. Nuclear extracts prepared from unstimulated lymphocytes of 5 healthy donors were used in lanes 2 to 6. As a control, an ATL cell nuclear extract was used in lane 1. B, LILRE was used as a radiolabeled probe. Nuclear extracts were obtained from untreated (lanes 1 and 3) and IL-1–treated (lanes 2 and 4) lymphocytes of 2 healthy donors. C, An ATL cell nuclear extract and radiolabeled hSIE (lanes 1 to 5) and SIE (lanes 7 to 11) probes were used. As a control study (lane 6), the ATL cell nuclear extract was incubated with a radiolabeled LILRE probe. D, LILRE (lanes 1 and 2) and hSIE (lanes 3 and 4) were used as radiolabeled probes. Lymphocytes preactivated by PHA treatment were not stimulated (lanes 1 and 3) or were stimulated with IL-2 (lanes 2 and 4). EMSAs were conducted as described in Figure 1.