Figure 2.

Interactive signaling between C3a and C5a stimulation observed in calcium transients. The time courses of anaphylatoxin-evoked Ca²⁺ transients in ARPE-19 cells were examined in cells exposed to anaphylatoxins alone or in combination (left panels), and peak and late phase amplitudes were analyzed (right panels). Simultaneous (A,B,C) versus consecutive (C,D) applications were tested. (A) Single application of C5a compared to the simultaneous co-application of C3a and C5a. (B) Single application of C3a compared to the simultaneous co-application of C3a and C5a. (C) Simultaneous co-application of C3a and C5a compared to consecutive application, where C5a was applied after C3a when the Ca²⁺ transient has reached a steady state indicated by arrow. (D) Single application of C3a compared to consecutive co-application of C3a followed by C5a. Anaphylatoxins were applied at concentrations of 260 nM (C3a) and 52 nM (C5a). Data are presented as mean values + SEM. Numbers of cells tested in two to seven independent experiments is indicated in the bars, *p < 0.05, ***p < 0.005 (Mann–Whitney U test).