Figure 3.

Inhibition of BCR-mediated Ca²⁺ mobilization by coligation with FcPD and PD-1. Cytosolic calcium concentrations of Fc-chimera transformants were measured with a KAF 110 spectrophotometer. Each transformant was stimulated by coligation of Fc chimera and BCR or ligation of BCR only. (A) FcPD inhibited BCR-mediated Ca²⁺ mobilization as efficiently as FcγRIIB and FcKIR. (B) FcPDF1 inhibited BCR-mediated Ca²⁺ mobilization, whereas FcPDF2, FcPDF1F2, and FcPDTM could not. (C) FcPD inhibited BCR-mediated Ca²⁺ mobilization in the presence of EGTA. (D) Inhibitory effect of full-length PD-1.