Background: The cattle tick, Rhipicephalus (Boophilus) annulatus, is one of the most abundant tick species worldwide, specifically in tropical and subtropical territories. This species is mainly found in North of Iran. Additionally, tick infestation usually provokes notable financial burden in livestock industry through blood loss, weight reduction, decreased lactation, anorexia, irritation, and toxic conditions such as paralysis and allergies. The tick control programs have frequently been relied on the utilization of anti-tick chemical · compounds, i.e. acaricids. However, the emergence of acaricid resistant tick populations and persisting of chemical residuals in animal productions, justify the demand for other prevention strategies. So far many proteins have been introduced as a vaccine candidate. One of the suggested anti-tick vaccine candidates is the actin-binding Tropomyosin protein. Tropomyosin protein plays an important role in regulating actin ction, immune and allergic reactions and vaccine production. Cathepsins are lysosomal proteases with several members such as cysteine, aspartic and serine proteases. The physiologic actions of cathepsins are enclosing degradation of intracellular and endocytosis-introduced extracellular proteins. Several methods are used for binding proteins. The overlap extension polymerase chain reaction (or OE-PCR) is designed t< attach two separate PCR products together that have been designed to have a short overlap of complementar] sequence. This overlap can be produced by the addition of bases to the ends of the internal primers for th respective PCR products. In this study we aimed to binding of two genes of Rhipicephalus annulatus tic larva as fused potent vaccine candidates, cathepsin and tropomyosin, using OE-PCR. Material and method: Reference sequence of tropomyosin and cathepsin proteins were obtained fro NCBI data base. Co111111on fragments of each proteins sequence among ticks, differing from those of co were selected. The specific primers (Forward, Reverse and complementary primers) were designed for 0 PCR. Two genes were linked to each other by OE-PCR and the PCR product was run on the agarose gel a sequenced by TakapouZist Company. Result and discussion: PCR product on the agaros gel showed a sharp band in intended spot. The resul sequencing confirmed these findings. Conclusion: There have been introduced several anti-Boophilus vaccines so far, but they were imped There is hope that in future it will become, possible to use this construct as a Protein Vaccine Candidate · none of the previous vaccine defects. This requires cloning and expression of these construct and inj into animals .

Keywords