The Rhipicephalus microplus tick is the major bovine ectoparasite in the tropical and subtropical regions of the world. R. microplus is the vector of Anaplasma sp and Babesia sp and responsible of several losses in livestock, because of the reduction in milk and meat production. At the moment the most common, and reliable, method of control is by chemical compounds that can promote tick resistant strains selection and the environment and bovine products contaminations, thus making necessary the development of different strategies for tick control. In the last few years a great effort has been done in the attempt to develop an anti tick vaccine. These studies allowed the development of two different products commercially available, the GAVAC and the TickGard Plus based on the same antigen, a midgut protein named Bm86. Although none of those vaccines display a high protection efficacy to Brazilian bovine. In order to contribute for the identification and characterization of new molecules important in tick life cycle that can be used as antigens for a vaccine development. Recently, our group performs a transcriptome analysis of the midgut from engorged female tick. Among the transcripts we identify a putative aspartic protease, contig Rm27441, which we selected for this study.Preliminary analysis reveals the presence of Rm27441 in several tick tissues, although in higher concentrations in midgut and fat body, tissues typically related to viteline and blood meal degradation. In the attempt to understand the physiological role of Rm27441 in R. microplus, the goals of this study are cloning, expression and purification of an aspartic protease (Rm27441) and test its as an antigen for vaccine development.
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