Molecular Characterization of Tick Galectin in Context of α-Gal Syndrome

α-Gal Syndrome (AGS) is a tick-borne delayed hypersensitivity reaction that occurs 3-6 hours after red meat consumption. It is induced by oligosaccharide galactose-α-1,3-galactose (α-gal) found in the Lone Star tick, Amblyomma americanum, and all mammalian-derived foods. α-gal specific IgE (sIgE) antibodies are produced after α-gal transmission from the tick bite and activates after subsequent red meat consumption. Previously, an immune-affinity approach utilized 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 involved in many physiological functions such as inflammation and immune responses. The goal of this study is to characterize the A. americanum Galectin protein and its involvement in AGS. 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. Galectin-silenced ticks showed impaired oviposition and increased microbial load. 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.