The Effects of Bacterial Endotoxin on Rabbit Platelets

The heat-labile plasma factor (HLPF) necessary for endotoxin-induced platelet injury in citrated plasma has been investigated. HLPF does not appear to be complement since no complement fixation occurs during the course of the platelet-endotoxin interaction. A functionally similar factor removed from plasma by zymosan appears to be the same in substitution experiments. The conditions employed in the zymosan adsorption also differentiate the adsorbed factor from complement. The relationship of this factor to properdin is discussed.