Ticks were maintained under laboratory conditions for two years prior to use in the experiments reported here. Cattle were

used to cycle the tick progeny. Tick stages requiring incubation were kept in the laboratory at 28 °C and 80% relative humidity. The Campo Grande cattle tick CDK inhibition strain is susceptible to commercially available acaricides. The expressed sequence tag (EST) coding for RmLTI (GenBank ID: CK186726[21] and [24]) was optimized for P. pastoris codon usage, and synthesized by Epoch Biolabs, Inc. Codon optimization was done using Epoch Biolabs, Inc. proprietary software set at 15% cut off for codon efficiency. This RmLTI DNA fragment was cloned into pPICZαA, producing the pPICZαRmLTI construct. The recombinant plasmid codes for a His tag that is added to the N-terminus of the protein product. Previously described procedures were followed to produce rRmLTI in the P. pastoris expression system [25]. Alignment, similarity, and discordance comparisons based on bioinformatics techniques were conducted between predicted amino acid sequences for: rRmLTI, EST CK186726, BmTI-6 from ovarian cDNA (GenBank ID: P83606.2), and N-terminal amino acid sequence information for BmTI-A (GenBank ID: P83609), BmTI-D (GenBank INCB024360 research buy ID: P83607), BmTI-2 (GenBank ID: P83603), and BmTI-3 (GenBank ID: P83604). ClustalW

from the BioEdit suite was used with Vector NTI® software (Invitrogen) as described previously to conduct the bioinformatics analyses [16]. The amino acid sequence from rRmLTI was submitted to protein function and superfamily analysis using the protein domains identifier software InterProScan [42]. Protein concentration in P. pastoris culture supernatant was quantified as described previously [25]. Proteins were precipitated with methanol and the precipitated proteins resuspended in denaturing binding buffer (8 M Urea, 20 mM sodium phosphate

pH 7.8, 500 mM NaCl). The rRmLTI was purified using a Ni2+ charged Ni-NTA (Qiagen, Hilden, Germany) affinity column with denaturing elution buffer (8 M Urea, 20 mM Sodium Phosphate pH 4.0, 500 mM NaCl) and the purification process monitored by 7.5% SDS-PAGE. Eluted fractions of high purity were pooled and dialyzed no against PBS. Animal care and use was conducted at EMBRAPA Beef Cattle according to institutional guidelines. Polyclonal serum against R. microplus larval extract or rRmLTI was produced using BALB/c mice as described previously [25]. The RmLTI vaccine was prepared with 500 μg of rRmLTI protein resuspended in 4 mL of 150-mM Tris–HCl at pH 7.4 and emulsified with 6 mL of Montanide ISA 61 VG (Seppic, Paris). Twelve female BALB/c mice were used, which were separated into two groups of six animals. One group received the rRmLTI formulation and the other the larval extract preparation. Each mouse within the respective group was immunized with 50 μg mL−1 dose−1 of rRmLTI, or 100 μg mL−1 dose−1 of larval extract. Three subcutaneous doses were applied at 21-day intervals.