PolyP directly affects the function of TP components. (A) In a purified system, P₁ (●) or polyP_>1000 (○) were titrated into the TP assay in the presence of 20 pM C5b,6 and excess C7, C8, and C9. PolyP suppresses the TP in a similar manner as in serum (Figure 2A). Results are representative of 3 experiments, each performed in triplicate. (B) The TP assay was performed by sequentially adding cRBCs, C5b,6, C7, C8, and C9, with 200 µM polyP_>1000 added at different steps, as indicated by arrows below the figure. Values were normalized to baseline lysis in the control condition without the addition of polyP. Each column represents quadruplicate data points. Relative lysis between control, after C7, and after C8 conditions were not statistically significant (P > .05).