Recombinant Expression And Biological Function Analysis Of Histamine Binding Proteins(HBPs) Of Ticks

Ticks are significant bloodsuking ectoparasites and they are a serious threat to livestock and human health. Ticks can cause a host of parasitic blood loss, anxiety and skin damage, and ticks are also vectors of various pathogens and transmit a number of important diseases. The penetration of tick mouthparts into the host skin causes inflammation response, blood clotting response, immune reaction. Tick salivary glands secrete a number of biological macromolecules to interference the response of host, such as anticoagulant molecules, immunosuppressive and anti-inflammatory molecules and other molecules. These molecules have the potential for the treatment of blood coagulation related diseases, tumors, as well as the other autoimmune diseases. Tick histamine binding protein(HBP) is one of these molecules which are secreted by the salivary glands of ticks. HBPs are not a single protein but a collection of a series of proteins.Hyalomma asiaticum belongs to Hyalomma, Ixodidae, which has three hosts, and widely distributed in the northwestern of China(Xin jiang, Inner Mongolia and Ning xia) and Central Asia. Ha HBP is one of histamine binding proteins which is cloned from the salivary glands of Hyalomma asiaticum. For a more detailed description on the biological fuction of Ha HBP, in this study, we performed works on Ha HBP on the base of the results we obtained. Firstly, in order to investigate the function of histamine binding protein of Hyalomma asiaticum(Ha HBP), Ha HBP was cloned intothe vector p Fastbac HTa, which was transformed into the receptor cells DH10 Bac, and the recombinant bacmid was acquired. The r Bacmid-Ha HBP was transfected into insect sf9 cells. Ha HBP were proved to efficiently express in sf9 cells by Western blot,SDS-PAGE and IFA assay. The molecular weight of Ha HBP was approximately 31 k Da, which was consistent with the predicted size. Secondly, Ha HBP which expressed in both prokaryotic and eukaryotic expression systems, was incubated with HRP-histamine in different concentrations. Histamine binding assay demonstrated that both of these two kinds of protein can bind to histamine. Thirdly, we studied the impact of Ha HBP to the skin inflammation and allergic asthma in mice, the results shows that Ha HBP can inhibit these two inflammatory response.Overall, the results provide great information for a further explaination on the study of new tick source antihistamines.