The effect of thrombin activated factor XIII. Thrombin and plasmin on the chemiluminescence produced by human neutrophils stimulated by opsonized zymosan (Mannozym

: Coagulation factor XIII formed by thrombin activation from zymogen factor XIII decreases the chemiluminescence (CL) of human neutrophils stimulated by opsonized zymosan (Mannozym). At high concentrations, thrombin and plasmin also decreased the CL induced by opsonized zymosan. The inhibitory effect of all the three enzymes was due to their influence on the cell membrane receptors (C3b and Fe) and not to their direct effect on opsonized Mannozym. The potential clinical role of factor XIII, thrombin and plasma in the regulation of neutrophil functions is assumed.