Molecular cloning, sequence analysis, and immune recognition of Bm95 from Thai strains of Rhipicephalus (Boophilus) microplus.

The efficacy of existing vaccines against Thai strains of Rhipicephalus (Boophilus) microplus remains to be determined, and these vaccine antigens should be compared to homologues derived from local strains. The purpose of this study was to compare Bm95 from Thai R. microplus to the previously reported sequence from Argentinean ticks. mRNA was isolated from R. microplus midgut samples, and cDNA was amplified with Bm95-specific primers. The cDNA and protein sequences of Thai Bm95 were 94 and 92% identical, respectively, to Argentinean Bm95. Although the sequence was similar to Argentinean Bm95, there were 45-amino acid differences among the homologues. Amplicons encoding Bm95 were cloned into pPICZalphaA and expressed in Pichia pastoris strain KM71H. The recombinant plasmid Bm95 (rBm95) was reactive to bovine hyperimmune serum to Thai R. microplus midgut, indicating that the Thai rBm95 was immunogenic. Further work is needed to compare the efficacies of Thai and Argentinean rBm95 for protection of cattle against infestation with Thai R. microplus.