Figure 2.

Complement mediated bacterial killing of TFPI-1 C-terminal peptides. (a-b) Bactericidal activity of TFPI-1 peptides was assessed under ex vivo conditions, using viable count analysis. E. coli bacteria were grown to mid-logarithmic phase and incubated with varying concentrations of peptides from mammals, birds, reptiles, and fish species. (a) Peptides were tested either in buffer containing 10 mM Tris, pH 7.4 alone or in presence of 20% citrated plasma from the corresponding host species. (b) Peptides (8 µM) were tested in presence of 20% citrated heat inactivated plasma from the corresponding host species. The bactericidal activity was determined by plating serial dilutions of bacteria on TH agar plates and the number of cfu was counted after overnight incubation. Data are presented as bacterial survival percentage; values are mean ± SD (n = 3) with a non-linear x-axis. (c) TFPI-1 peptides recruit the classical complement pathway.