Figure 7.

rTsCRT-S inhibits human PMN formation of neutrophil extracellular traps (NETs) through inhibiting C1q-initiated classical complement activation. (A) PMN release of free DNA was measured on treatment with C1q (2 µg) pre-incubated with rTsCRT-S or rTsCRT (0, 0.1, 0.3, and 0.9 µM) or BSA (0.9 µM). C1q-D serum and IC were added to activate the classical complement pathway. The free DNA experiment was repeated three times. Data are shown as means ± SEM (*p < 0.05, **p < 0.01; ns = no significant difference). (B) NETosis was visualized using scanning electron microscopy (SEM) and confocal immune fluorescence microscopy (IF). Reduced NETosis, and PMN release of NE and histone H3, were observed when C1q was incubated with rTsCRT-S and rTsCRT, but not the BSA control. The black scale bars of the SEM represent 30 µm, and the white scale bars of the IF represent 50 µm. Arrowheads indicate the NET formation.