Proteomic Analysis of Cattle Tick <i>Rhipicephalus</i> (<i>Boophilus</i>) <i>microplus</i> Saliva: A Comparison between Partially and Fully Engorged Females

<div><p>The cattle tick <i>Rhipicephalus</i> (<i>Boophilus</i>) <i>microplus</i> is one of the most harmful parasites affecting bovines. Similarly to other hematophagous ectoparasites, <i>R. microplus</i> saliva contains a collection of bioactive compounds that inhibit host defenses against tick feeding activity. Thus, the study of tick salivary components offers opportunities for the development of immunological based tick control methods and medicinal applications. So far, only a few proteins have been identified in cattle tick saliva. The aim of this work was to identify proteins present in <i>R. microplus</i> female tick saliva at different feeding stages. Proteomic analysis of <i>R. microplus</i> saliva allowed identifying peptides corresponding to 187 and 68 tick and bovine proteins, respectively. Our data confirm that (i) <i>R. microplus</i> saliva is complex, and (ii) that there are remarkable differences in saliva composition between partially engorged and fully engorged female ticks. <i>R. microplus</i> saliva is rich mainly in (i) hemelipoproteins and other transporter proteins, (ii) secreted cross-tick species conserved proteins, (iii) lipocalins, (iv) peptidase inhibitors, (v) antimicrobial peptides, (vii) glycine-rich proteins, (viii) housekeeping proteins and (ix) host proteins. This investigation represents the first proteomic study about <i>R. microplus</i> saliva, and reports the most comprehensive Ixodidae tick saliva proteome published to date. Our results improve the understanding of tick salivary modulators of host defense to tick feeding, and provide novel information on the tick-host relationship.</p>