Fig. 5. Antigens, anti-FcRs and anti-IgE increase cytosolic Ca²⁺ levels and CaN activity in human neutrophils. (A) Fura-2-AM-loaded neutrophils from an allergic patient sensitised to G₃ were treated at the times indicated with 10 µg/ml anti-IgE (-IgE) (1), 10 µg/ml G₃ (2), 50 nM fMLP (3), 5 µg/ml anti-galectin-3 (-galectin-3) (4), 5 µg/ml anti-FcRI (-FcRI) (5), or 5 µg/ml anti-FcRII (-FcRII) (6), and cytosolic Ca²⁺ was spectrofluorometrically recorded for 2 minutes. Each graph is representative of a set of three experiments that yielded similar results. (B) Neutrophils from an allergic patient sensitised to E₁ were incubated with 10 µg/ml anti-IgE (-IgE), 10 µg/ml E₁ antigen, or unspecific goat IgG (IgG) for the indicated times. Then, the cells were lysed, and CaN activity was assayed. Values are the means ± s.e.m. from four separate experiments performed in triplicate.