Fig. 6.
FcαRI-mediated IL-1β pre-mRNA splicing and protein synthesis in human platelets. (A) Cross-linking of platelet FcαRI induced mature IL-1β mRNA production. Purified human platelets (5×108) were stimulated with anti-FcαRI mAb A59 F(ab′)2 plus goat anti-mouse IgG F(ab′)2 (Anti FcαR-marked lanes), with hIgA plus goat anti-hIgA F(ab′)2 (hIgA-marked lanes) or without stimulation (lane labeled as Non). Total RNA was isolated from platelets pellets and used for RT-PCR. The results were representative of at least four independent experiments. (B) Induction of IL-1β release by clustering platelet FcαRI. The platelets (2.5×108) were stimulated with plate-bound mIgG F(ab′)2, thrombin plus fibrinogen, anti-FcαRI mAb A59 F(ab′)2, and hIgA, respectively. IL-1β in culture supernatants was quantified with ELISA at 5 h and 20 h time-points. The data represent the mean ± sem of four independent experiments. *, Significant differences between platelets stimulated with plate-bound A59 F(ab′)2 or hIgA and platelets stimulated with fibrinogen plus thrombin or mIgG F(ab′)2 (P<0.0001).