Figure 1. Meglumine gadoterate (MeGa) induces mast cell (MC) activation and MRGPRX2 internalization without affecting cell viability. LAD2 cells were stimulated with different concentrations of GBCAs (MeGa, gadobutrol, gadoxetate disodium and gadoteridol) or vehicle control (-), and activation (A) and viability (B) were assessed by flow cytometry. Gating strategy and fluorescent minus one (FMO) control used to determine MRGPRX2 expression by flow cytometry(C). Geometric median fluorescence intensity (MFI) of MRGPRX2 following LAD2 cell stimulation with vancomycin (VAN, positive control) and MeGa, represented as the percentage of MRGPRX2 expressed by media-stimulated LAD2 cells (D) . Pooled data from 3-4 independent experiments represented as mean ± SEM, *p≤0.05; **p≤0.01; ***p≤0.001.