PolyP suppresses the TP in a size-dependent manner. (A) P₁ (●), polyP_<30 (□), polyP_40-160 (▪), and polyP_>1000 (○) were titrated into the TP assay in the presence of 2% serum and 250 pM C5b,6. The IC₅₀ is shown only for polyP_>1000. The TP was suppressed in a size-dependent manner. Results are representative of 3 experiments, each performed in triplicate. (B) On the left, 100 µM of different size polyPs were added to the TP assay as above. On the right, the different-size polyPs used in the TP assay were separated on a Tris-Borate-EDTA-urea gel and stained with toluidine blue. *Comparisons to control without phosphate (P < .001; n = 4).