ANTIHEMOSTATIC ACTIVITY IN SALIVARY-GLANDS OF THE HUMAN-BODY LOUSE, PEDICULUS-HUMANUS-HUMANUS (ANOPLURA, PEDICULIDAE)

A thrombin inhibitor, factor Xa inhibitor and apyrase activity were de monstrated in the salivary glands of Pediculus humanus humanus, Less t han 0.15 mu g of salivary gland extracts (SGE), which is equivalent to approximately 0.15 lice salivary glands, caused 50% inhibition of thr ombin activity, while 1 mu l of SGE was sufficient to double thrombin time using rat plasma, A single peak of thrombin inhibitor was eluted from the Mono Q column at a fraction corresponding to a protein with M ol, Wt. of about 7 kDa, The thrombin inhibitor was partially purified from the SGE by gel filtration chromatography and FPLC chromatography, and a single sharp peak of thrombin inhibitory activity was eluted, T he results obtained from the FXa activity assay indicate the presence of a weak inhibitory activity against this coagulation factor in the s alivary gland, The amount of SGE needed for FXa inhibition (IC50) was 500 times higher than that required for thrombin inhibition, Apyrase a ctivity was also detected in the SGE using ADP as a substrate, These r esults indicate the presence of both anticoagulant and anti-platelet a gents in the salivary gland of the human louse. Copyright (C) 1996 Els evier Science Ltd