Inhibitory effect of KIR on TCR-mediated ZAP-70 and LAT tyrosine phosphorylation.

(A) Postnuclear lysates of nonstimulated CTLs (lane 1) or stimulated by LCLs or RCC targets were immunoprecipitated with polyclonal anti–ZAP-70 (top panel) or anti–LAT antibody (bottom panel) and analyzed for tyrosine phosphorylation (left panels). Densitometric values are indicated in italics. (B) Same conditions of immunoprecipitation as in (A) of CTLs (lane 1) stimulated by RCC-7 (lane 2), masking of KIR ligand with anti–HLA-B/C (lane 3), or control anti–HLA-DR mAbs (lane 4) before stimulation. Bottom panels (WB ZAP-70 and WB LAT) show membrane reprobing with corresponding antibodies specific for precipitated proteins.