Inhibition of bovine platelets aggregation in response to Hyalomma anatolicum salivary gland proteins/peptides

AIM Ticks are obligate ectoparasites that have an impact on wide range of vertebrates and also act as a potential vector for the transmission of tropical theileriosis, babesiosis, etc., causing significant loss to livestock production worldwide. While feeding, they introduce their saliva containing different bioactive molecules into the host. These molecules have the capability to counteract the host hemostatic mechanism to suck host blood successfully. Therefore, the study was aimed to isolate anti-platelet aggregating peptides from salivary gland extract (SGE) of Hyalomma anatolicum ticks, a commonly available tick in India. MATERIALS AND METHODS Female H. anatolicum salivary glands were dissected out and SGE was prepared by homogenizing it in a suitable buffer under ice. Extract so obtained was fractionated by gel filtration chromatography using Sephacryl S-200 column. Total protein concentration in fractions was estimated and bovine platelets were isolated, stimulated with thrombin (positive control), treated with Gly-Pro-Arg-Pro amide (negative control) and with salivary gland fractions for identification of proteins/peptides having anti-platelet aggregating activities. RESULTS Proteins/peptides present in various salivary gland fractions inhibited the bovine platelet aggregation and the percent inhibition ranged between 33% and 35.8%. CONCLUSION The results suggests that the fractions of H. anatolicum salivary glands possess thrombin-induced anti-platelet aggregating activity and which could be further exploited for raising anti-tick vaccine and also for therapeutic purpose.