Comparison of recombinant Culicoides allergens produced in different expression systems for IgE serology of insect bite hypersensitivity in horses of different origins.

The research article studies the reaction of horses to a certain type of insect allergen to understand the prevalence of Insect Bite Hypersensitivity (IBH) an allergic condition found in horses. It particularly seeks to clarify the difference in the incidence of IBH in Icelandic horses born in Iceland and those born in areas populated with the allergy-causing insect, the Culicoides midges. It also evaluates the efficiency of barley as a system for allergen production for IBH immunoassays.

Objective

• This research mainly has two goals. Firstly, to compare the levels of IgE (a type of antibody associated with allergic reactions) in the sera of IBH-affected Icelandic horses born in Iceland with horses of the same breed and different breeds born in a Culicoides infested environment. Secondly, to examine whether barley can be an efficient allergen production system for IBH immunoassays.

Methodology

• The scientists performed tests on Iceland-born IH-affected horses and both Icelandic and other breeds born in Culicoides populated areas. They used an ELISA test (a common test for measuring immune system responses) to check for antibodies, specifically IgE, against two recombinant (artificially created) Culicoides allergens: rCul n 3 and rCul n 4.
• These allergens were produced in three different environments: E. coli, insect cells, and barley.

Findings

• The researchers found significantly higher IgE levels in sera from IH-affected horses compared to healthy horses, indicating those with IH had a stronger reaction to the allergens.
• Specifically, Icelandic-born Icelandic horses had higher IgE levels against the allergens and a larger area under the curve (AUC) on rCul n 4 compared to the European-born horses. This may mean that they are more susceptible to the allergic reaction.
• The allergens produced in barley and E.coli had very similar performance in distinguishing between IBH-affected and healthy horses, leading to the conclusion that barley could be a viable system for allergen production for IBH immunoassays.