Molecular characterization of tick galectin in context of α-Gal syndrome

α-Gal Syndrome is a tick-borne delayed hypersensitivity reaction that occurs 3-6 hours after red meat consumption. It is induced by the oligosaccharide galactose-α-1,3-galactose (α-gal) found in the Lone Star tick and all mammalian-derived foods. α-gal specific IgE (sIgE) antibodies are produced after α-gal transmission from the tick bite and activated after subsequent red meat consumption. Previously in our lab, an immune-affinity approach utilized an α-Gal antibody to isolate and identify covalently linked tick saliva antigens to α-gal followed by Liquid Chromatography-tandem Mass Spectrometry (LS-MS/MS) analysis. The identified antigen included tick salivary Galectin, a carbohydrate-binding protein that is involved in many physiological functions such as inflammation and immune responses. The goal of this study is to characterize the Lone Star tick Galectin protein and its involvement in α-Gal Syndrome. Our qRT-PCR results revealed decreased gene expression of Galectin in different stages of the bloodmeal. We utilized an RNA interference (RNAi) approach to silence Galectin gene expression and assessed the functional consequences of gene depletion on tick behavior, phenotype, and tick molting. The silencing of Galectin did not have a significant impact on α-gal. However, Galectin knockdown (KD) did cause a significant downregulation in galactose metabolism-related genes including Galactose 1-phosphate uridyltransferase (GALT), Galactokinase (GALK), and α-D-galactosidase (AGS). Galectin-silenced ticks showed impaired oviposition as well as increased microbial load in the salivary glands. We are currently conducting experiments to further characterize the role of Galectin in microbial maintenance, galactose metabolism, and reproductive development to determine possible links between Galectin and α-gal.