Figure 7.
ILT2-class I interaction inhibits TSST-1–mediated T cell cytotoxicity. HP-F1+ T cell clones were generated from the peripheral blood of a healthy donor and selected for expression of TCR-Vβ2 and for lack of KIR expression. T cell clones were then tested in a 4-h 51Cr-release assay for cytotoxicity against the class I–negative B lymphoblastoid cell line 721.221 cells or 721.221 cells stably transfected with HLA-B*2705, in the presence of serial dilutions of TSST-1 at an effector/target ratio of 20:1. The T cell clone OKT8-24 killed 721.221 in the presence of TSST-1, but did not kill B*2705-transfected cells. F(ab′)2 fragments of the HP-F1 mAb partially restored the lysis, while F(ab′)2 fragments of the isotype-matched anti-CD56 mAb had no effect.