Identification and characterization of Rhipicephalus (Boophilus) microplus candidate protective antigens for the control of cattle tick infestations

Abstract

The cattle ticks, Rhipicephalus (Boophilus) spp., affect cattle production in tropical and subtropical regions of the world. Tick vaccines constitute a cost-effective and environmentally friendly alternative to tick control. The recombinant Rhipicephalus microplus Bm86 antigen has been shown to protect cattle against tick infestations. However, variable efficacy of Bm86-based vaccines against geographic tick strains has encouraged the research for additional tick-protective antigens. Herein, we describe the analysis of R. microplus glutathione-S transferase, ubiquitin (UBQ), selenoprotein W, elongation factor-1 alpha, and subolesin (SUB) complementary DNAs (cDNAs) by RNA interference (RNAi) in R. microplus and Rhipicephalus annulatus. Candidate protective antigens were selected for vaccination experiments based on the effect of gene knockdown on tick mortality, feeding, and fertility. Two cDNA clones encoding for UBQ and SUB were used for cattle vaccination and infestation with R. microplus and R. annulatus. Control groups were immunized with recombinant Bm86 or adjuvant/saline. The highest vaccine efficacy for the control of tick infestations was obtained for Bm86. Although with low immunogenic response, the results with the SUB vaccine encourage further investigations on the use of recombinant subolesin alone or in combination with other antigens for the control of cattle tick infestations. The UBQ peptide showed low immunogenicity, and the results of the vaccination trial were inconclusive to assess the protective efficacy of this

The mitochondrial genome of a Texas outbreak strain of the cattle tick, Rhipicephalus (Boophilus) microplus, derived from whole genome sequencing Pacific Biosciences and Illumina reads

“…Some of these differences raise questions about existing species classifications of the R. microplus ticks. It is important to correctly identify and classify cattle tick populations because some tick control methodologies, particularly the use of anti-tick vaccines in cattle, show inconsistent results (Almazán et al 2010). Genomic variation among tick population that have been misclassified as a single species might be the reason for this inconsistency.…”

RNA Interference – A Powerful Functional Analysis Tool for Studying Tick Biology and its Control

“…(B.) microplus reduced the engorged body weight and egg output [45]. In contrast, a study on A. maculatum showed that silencing two selenoproteins did not alter blood feeding, although the egg output was reduced.…”

“…(B.) microplus [45]. It also made R. sanguineus ticks more susceptible to permethrin, although no significant effects on tick attachment, feeding and reproductive capacity were observed [137].…”

“…(B.) microplus [42,[45][46][47], A. americanum, I. scapularis, and D. variabilis adults [43], which produced significant effects on the eggs and larvae, and microinjection has also been accomplished in I. scapularis [48][49][50][51][52] and engorged O. moubata nymphs [53].…”

“…(B.) microplus and R. annulatus [45] has been employed to screen potential antigens for tick control.…”