Mohammad Mehdi Ranjbar - Razi Vaccine and Serum Research Institute, Agricultural Research, Education and Extension Organization (AREEO), Karaj, Iran
Gholamreza Karimi - Razi Vaccine and Serum Research Institute, Agricultural Research, Education and Extension Organization (AREEO), Karaj, Iran
Nabali Ahmadi - Proteomics Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran
Sajjad Yazdansetad - Infectious Diseases Research Center, Golestan University of Medical Sciences, Gorgan, Iran

Background: The tick-borne diseases cause significant economic losses in animals and humans. The tickmidgut surface protein Bm۸۶ of Ripsephalus spp. is considered as an immunoreactive antigen for vaccinecandidate against cattle fever ticks. In this bioinformatics report, we focused on the computationallyoptimized broadly reactive antigen (COBRA) tool to decipher the tick midgut protein Bm۸۶ for vaccinestrategy in the fight against Rhipicephalus species.Materials and Methods: In this bioinformatics analysis, the consensus sequences of R. microplus and R.annulatus were retrieved, aligned with the GenBank data using the BLASTN algorithm and Sequencher v۴.۸program, and finally edited. The phylogenetic trees were built using the maximum likelihood method. Bm۸۶-based vaccine using the COBRA method was designed according to the taxa grouping and the center-of-tree(COT) sequences. The protein superimposition algorithms and molecular modeling analysis were also carriedout.Results: The hypervariable regions were identified in the amino acid residues ۱۷۷-۱۸۱, ۲۷۰-۲۷۶, and ۳۵۱-۳۵۲, respectively in both R. microplus and R. annulatus sequences. Six sequences were selected to anticipatethe evolutionary vaccine and ۱۲ sequences were used to realign and obtain the consensus sequences to doCOBRA. R. annulatus sequences were in sister branches with more similarity to each other compared toBm۸۶ protein sequences in R. microplus except ADQ۱۹۶۸۷. The sequences AJE۲۹۹۳۱, AJE۲۹۹۳۲,ATW۷۵۴۷۲, ATW۵۴۷۶, ADM۸۶۷۲۲, and ACZ۵۵۱۳۳ were selected for vaccine designing according to theancestral center-of-tree (COT).Conclusion: Anti-tick vaccines using the COBRA approach could be a more cost-effective alternative witha broader spectrum compared to the commonly used recombinant vaccines.

Rhipicephalus; Bm۸۶; Phylogeny; Vaccine; COBRA