Proteomics reveals the hemolymph components of partially fed Hyalomma asiaticum ticks

Hemolymph infection facilitates pathogen invasion of internal tick tissues. However, the overall protein composition of the hemolymph has not been analyzed for any tick species. Here, a gel based liquid chromatography tandem mass spectrometry method was used to characterize the hemolymph proteome of Hyalomma asiaticum females during blood feeding. A total of 311 proteins were identified. Hemelipoglyco-carrier proteins, apolipophorin-like proteins, and intracellular proteins were the most abundant proteins. Thirteen immunity-related proteins were identified, including peptidoglycan recognition protein (PGRP), Thioester-containing proteins (TEPs), clip‑serine proteinases, serpins and Dome. The presence of hemocytin, proclotting enzyme homologs, serpins, TEPs, factor D-like protein and the lack of coagulin, hemocyanin, and prophenoloxidase suggest ticks may possess a unique coagulation system, which is largely different from that of insects. Taken together, the study revealed the constitution, level, and possible functions of global hemolymph proteins in H. asiaticum and could facilitate the discovery of new targets for control of tick-borne pathogens.