Measurement of NFκB dependent secreted alkaline phosphatase (SEAP) levels in HEK293 cells expressing a single TLR or NLR at 20 h following exposure in DMEM complete medium to GdBCA. Cells were exposed to 0.5, 1 and 5 mM concentrations of the linear GdBCA Gd-DTPA, MultiHance®, OptiMark®, Omniscan® or gadodiamide, or of the macrocyclic GdBCA Dotarem® or ProHance®, or to 0.27, 2.7 or 27 μM of the Gd compounds Gd-EDTA or Gd-Citrate or to 0.025, 0.05 or 0.25 mM of the non-Gd chelate molecule caldiamide. LPS (1 mg/mL) and gardiquimod (10 mg/mL) were used as positive controls for TLR4 and TLR7 activation respectively. Values represent the mean (+/− SD) absorbance at 650 nm of 3 replicate of 3 separate experiments on HEK293 cells in culture. Statistical significance was calculated by comparing each Gd compound to the saline control. Values for other samples are expressed relative to the saline control. *: p<0.05; **: p < 0.01; ***: p<0.001. A. SEAP levels secreted in response to exposure to the highest concentration of each agent tested. B. Three concentration dose response of SEAP levels secreted following exposure to Dotarem®, MultiHance®, Omniscan® or gadodiamide.