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Background: The cattle tick, Rhipicephalus (Boophilus) microplus, affects livestock production in many regions of the world. Up to now, the widespread use of chemical acaricides has led to the selection of acaricide-resistant ticks and to environmental contamination. Gavacplus is a subunit vaccine based on the recombinant Bm86 tick antigen expressed in yeast, capable to control infestations of R. microplus under controlled and production conditions. The vaccine constitutes the core element of broad control programs against this ectoparasite, in which acquired immunity in cattle to Bm86 is combined with a rational use of acaricides. At present, the conventional vaccine scheme consists of three doses that should be administered at weeks 0, 4 and 7, followed by a booster every six months. Results: In this study we assayed a reduction in the number of the initial doses of Gavacplus, evaluated the time course and the level of bovine anti-Bm86 antibodies elicited, and analyzed the vaccine effect on ticks engorging on immunized cattle under production conditions. Following three different immunization schemes, the bovines developed a strong and specific immune response characterized by elevated anti-Bm86 IgG titers. A reduction in the weight of engorging female ticks, in the weight of the eggs laid and also in R. microplus viable eggs percentage was obtained by using only two doses of Gavacplus administered at weeks 0 and 4, followed by a booster six months later. This reduction did not differ from the results obtained on ticks engorging on cattle immunized at weeks 0, 4 and 7. It was also demonstrated that anti-Bm86 antibody titers over 1:640, measured in bovines immunized at weeks 0 and 4, were sufficient to affect weight and reproductive potential of female ticks as compared with ticks engorging on unvaccinated animals. In addition, no statistically significant differences were detected in the average weight of eggs laid by ticks engorged on immunized cattle that showed anti-Bm86 specific titers in the range of 1:640 to 1:81920. Conclusion: The administration of two initial doses of Gavacplus containing 100 μg of Bm86 antigen to non-immunized cattle under production conditions is sufficient to affect the weight and the reproductive capacity of R. microplus engorging females. According to these results, cattle herds' manipulation and vaccine costs could be potentially reduced with a positive impact on the implementation of integrated control programs against R. microplus. [ABSTRACT FROM AUTHOR]

Keyhole limpet haemocyanins (KLH1 and KLH2) from Megathura crenulata , are multi-subunit oxygen-carrying metalloproteins of approximately 3900 amino acids, that are widely used as carrier proteins in conjugate vaccines and in immunotherapy. KLHs and their derived conjugate vaccines are poorly characterized by LC-MS/MS due to their very stable supramolecular structures with megadalton molecular mass, and their resistance to efficient digestion with standard protocols. KLH1 and KLH2 proteins were conjugated to the conserved P0 peptide (pP0), derived from the P0 acidic ribosomal protein of Rhipicephalus sp. ticks using maleimide-thiol chemistry to obtain a broad-spectrum anti-tick vaccine. The resulting KLH1- and KLH2-Cys 1 pP0 conjugate vaccines were efficiently digested using the Multiple-Enzymatic Digestion Filter Aided Sample Preparation and analyzed by LC-MS/MS, enabling a sequence coverage of approximately 85% of both conjugates. Seventy-three and sixty-five percent of all lysine residues in KLH1 and KLH2, respectively, were partially conjugated to Cys 1 pP0. In the quaternary structures, we found no bias toward conjugation of lysine residues exposed to either the outer surface or the inner channel. The latter may not contribute to a protective humoral response because B cell entry into the inner channel is incompatible with the entrance hole diameter. The Cys-His thioether bonds in both KLHs were determined by identifying type 1 cross-linked peptides. New post-translational modifications undescribed for the KLH such as oxidized species, were identified. This is the first report of the identification of conjugation sites of two KLH-based vaccines. These results will help translate the KLH-based conjugates into well-characterized biotechnology products.

Ticks and the vast array of pathogens they transmit, including bacteria, viruses, protozoa, and helminths, constitute a growing burden for human and animal health worldwide. In Cuba, the major tropical island in the Caribbean, ticks are an important cause of vector-borne diseases affecting livestock production, pet animal health and, to a lesser extent, human health. The higher number of tick species in the country belong to the Argasidae family and, probably less known, is the presence of an autochthonous tick species in the island, Ixodes . Herein, we provide a comprehensive review of the ticks and tick-borne pathogens (TBPs) affecting animal and human health in Cuba. The review covers research results including ecophysiology of ticks, the epidemiology of TBPs, and the diagnostic tools used currently in the country for the surveillance of TBPs. We also introduce the programs implemented in the country for tick control and the biotechnology research applied to the development of anti-tick vaccines.capromydis . Herein, we provide a comprehensive review of the ticks and tick-borne pathogens (TBPs) affecting animal and human health in Cuba. The review covers research results including ecophysiology of ticks, the epidemiology of TBPs, and the diagnostic tools used currently in the country for the surveillance of TBPs. We also introduce the programs implemented in the country for tick control and the biotechnology research applied to the development of anti-tick vaccines., Competing Interests: The authors declare no conflict of interest.