Research projects

Ticks are known to harbor bacterial communities with commensal, parasitic, and symbiotic relationships. By characterizing the lone star tick microbiome, we observed that it is mainly comprised of taxa that contain typical soil- and plant-associated bacterial members, suggesting that these bacteria were acquired from the environment. Due to the frequency and abundance of Bacillus sp. found in field-collected ticks, we sought to isolate different Bacillus species from field-collected ticks and other naturally occurring spore-forming bacterial taxa that could be detrimental to ticks, including those that kill ticks or render them unable to feed. Our ultimate goals are to identify microorganisms that can significantly reduce tick survival and colonize the tick gut, for the development of novel tick management strategies, and as a tool to better understand the tick-microbiome interactions and their role in tick vector competence.

Red meat allergy (RMA), or alpha-Gal syndrome (AGS), is caused by the increased production of IgE antibodies against galactose-alpha-1,3-galactose (alpha-gal or aGal). This glycan is found in most mammals, except for Old World monkeys and humans. AGS or RMA is observed in susceptible individuals after the ingestion of red meat, with a clinical manifestation of urticaria and anaphylaxis, and previous reports suggest that the main cause for the initial sensitization is A. americanum tick bites. We are currently testing whether lone star ticks mediate the transmission of the aGal sensitizer acquired from nonhuman blood to humans in the intrastadial host switch using an alpha-galactosyltransferase knockout mutant mouse (αGT-KO) model system, in which unfed ticks or ticks partially fed bovine blood were placed. Our results showed that αGT-KO mice significantly responded to tick feeding as evidenced by increased total IgE and aGal-specific IgE levels compared to those in control mice. This study confirmed that aGT-KO mice can be used as a model for studying RMA. The overall goal of this work is to better understand this immunological response to tick bites to aid in the future development of an anti-tick vaccine or anti-aGal-tick vaccine, which could help reduce the incidence of tick-borne illnesses.