Sugars in tick saliva are not sweet in red meat allergy

Alpha-gal syndrome (AGS or red-meat allergy) is often a life-long condition characterized by the clinical manifestation of urticaria and anaphylaxis to dietary red meat. Hyperreaction to a xenoglycan alpha-gal (aGal, galactose-alpha-1,3-galactose) by enhanced production of IgE antibody results in AGS. In addition, individuals with AGS can have anaphylactic responses to cetuximab, a murine-derived monoclonal antibody against cancer, and the rejection of transplanted porcine cardiac valves. AGS is thought to be caused by tick bite injecting tick saliva containing aGal, which was demonstrated in the alpha-galactosyltransferase knockout mouse model system (αGT-KO) lacking aGal. Interestingly, AGS occurs only in a subset of people experiencing tick bites, implying the presence of variations in the causal factor, tick bites, and in human response to the tick bites. In this presentation, I will present our studies chasing the AGS risk factors; the variable factors in the lone star tick Amblyomma americanum and in the AGS patients.