Impact of vaccine against antimicrobial tick peptides on microbiota and tick susceptibility to entomopathogens

• Grant number: 21/11677-8
• Support Opportunities: Scholarships in Brazil - Post-Doctoral
• Start date: June 01, 2022
• End date: May 31, 2024
• Field of knowledge: Biological Sciences - Immunology - Applied Immunology
• Principal Investigator: Isabel Kinney Ferreira de Miranda Santos
• Grantee: Jéssica Fiorotti de Paulo
• Host Institution: Faculdade de Medicina de Ribeirão Preto (FMRP). Universidade de São Paulo (USP). Ribeirão Preto , SP, Brazil

Abstract

The frequent and indiscriminate use of acaricides has led ticks to become resistant to almost all chemical classes available for their control. Thus, new technologies to control ticks must be developed, such as vaccines and biological control with entomopathogens. The cattle tick is a monoxene ectoparasite. Consequently, its bovine host has enough time to develop an adaptive immune response to the salivary proteins it secretes into the feeding pool to mediate parasitism. However, most salivary proteins are not immunogenic in commercially important cattle breeds, but that are genetically susceptible to ticks. This lifestyle also provides prolonged exposure of the parasite to the host's skin microbiota, possibly shaping its own microbial composition, which is essential for its survival. Tick saliva contains many types of antimicrobial peptides (AMPs). In this context, we predict that immunity to tick AMPs will change the microbial landscape of the tick-host interface. With PacBio sequencing of full-length rDNA 16S and bioinformatic and statistical treatment of the generated reads, we will examine the skin microbiome of tick-susceptible cattle immunized with a multivalent vaccine containing AMPs or with adjuvant, and the microbiome of ticks feeding on these same hosts and controls. We will also examine if females fed or not on vaccinated bovines are rendered more susceptible to established agents of biological control and if new candidate entomopathogens appear in these ticks when exposed to soil microorganisms. The results obtained in this study may open new venues for improvements in tick control by substituting harmful chemicals with an association between entomopathogens as biological control agents and vaccines that neutralize tick salivary mediators of parasitism. (AU)