Role of Tick Spit in Red Meat Allergy

Bites from the Lone-Star tick (Amblyomma americanum) have been implicated in an unusual delayed allergic reaction to red meat. Sensitization to oligosaccharide galactose-α-1,3-galactose (α-Gal) has been shown to be the mechanism of anaphylactic reaction in red meat allergy following tick bites. A. americanum is uniquely associated with symptoms of red meat hypersensitivity, and the geographic range of A. americanum includes states with highly rural populations. Given the nature of agriculture, forestry, and livestock workforce, there will inevitably be tick encounters simply by living in areas where A. americanum also resides. There is no cure for food allergies, and strict avoidance of the food allergen or trigger is the only way to prevent a reaction. Our long-term goal is to identify α-1,3-galactose in the Amblyomma tick species responsible for inducing delayed anaphylaxis, and to develop a dependable diagnostic test for the screening of red meat allergy. This exploratory grant application builds upon the investigation of the largely unexplored field of tick saliva proteions, with the aim to elucidate mechanistic relationships that tie together tick α-gal to the production of IgE in red meat allergy patients. In this project, a combination of molecular, immunological, biochemical, and reverse genetic approaches will be used to pursue following objectives: 1) Identify the tick salivary proteins responsible for the induction of red meat allergy using an immune-proteome approach, and 2) define the functional role of the identified tick proteins in the production of IgE antibodies in human red meat allergy using in vitro assays. Establishing the mechanism of the specific IgE antibody response to α-gal will be an important aspect to address in this area of research. This information is vital for early and quick recognition and treatment of allergic reactions that may lead to anaphylaxis, preventing serious health problems or death in unsuspecting allergy sufferers.