Evaluation of Rhipicephalus microplus hebrain expression in response to Anaplasma marginale and Staphylococcus saprophyticus infection

Abstract

The tick R. microplus, is the species with the highest economic and health incidence due to its expoliative and vectorial capacity of transmission of infectious agents such as Babesia bigemina, Babesia bovis and Anaplasma marginale. In this regard, R. microplus has a wide variety of protective immunological mechanisms, including the production of antimicrobial peptides. Currently, there are few reports of the role of the immune system of R. microplus, when exposed to pathogenic bacteria. Therefore, this work aims to characterize some of the immunological mechanisms involved in the pathogen-vector interaction, associated with the immune response of R. microplus during infection with Staphylococcus saprophyticus and Anaplasma marginale. Our results show the expression of the hebrain in presence of hemolymph of ticks infected with A. marginale, and, hemolymph of ticks without infection, but absent inn ticks infected with S. saprophyticus. Interestingly, the 3D structure of the hebrain, revealed tertiary structure similar to defensin´s family, with six conserved cystein residues. Finally, the phylogenetic analyses, to determinate evolutionary distances, showed the hebrain sequence as a monophyletic group, grouped in a clade along with other ticks species. These findings corroborate the idea of ​​the high plasticity that the arthropod immune response presents, dependent on the pathogen. The advance in the knowledge of the biology of R. microplus, contributes to the discovery of targets, for the development of new drugs and / or vaccines for the integrated control of pests.