Production of monoclonal antibodies specific for native equine IgE and their application to monitor total serum IgE responses in Icelandic and non-Icelandic horses with insect bite dermal hypersensitivity.

The study investigates the production of novel monoclonal antibodies to detect a component of serum antibody (IgE) in horses. This research is significant as it highlights the role IgE and mast cells play in allergic diseases in horses. It further explores the relation between concentrations of IgE in Icelandic and non-Icelandic horses susceptible to allergic reactions to insect bites.

Production of Novel Monoclonal Antibodies

• The researchers synthesized several new forms of monoclonal antibodies to monitor the presence of native equine Immunoglobulin E (IgE) in horses.
• Different techniques such as immunohistology, ELISA (Enzyme-Linked Immunosorbent Assay), and Western blotting were used to detect the presence of equine IgE.
• An ELISA audio test was developed using two of these antibodies to quantify equine IgE in serum.
• In the group of 122 adult horses studied, the average serum IgE concentration was measured at 23,523ng/ml, with a range varying from 425 to 82,610ng/ml.

Comparing IgE Concentrations in Healthy and Allergic Horses

• The researchers compared the total serum IgE of healthy horses with those horses affected with Insect Bite Dermal Hypersensitivity (IBDH), a common allergic reaction in horses to the bites of blood-feeding insects belonging to Culicoides or Simulium spp.
• IBDH does not occur in Iceland due to the absence of these species of insects. However, once imported into mainland Europe, native Icelandic horses show an unusually high incidence of this condition.
• The study revealed that Icelandic horses with IBDH had significantly higher total IgE than healthy Icelandic horse controls.
• This contrasted with non-Icelandic horses, where the difference in total serum IgE between those affected with IBDH and healthy controls was not statistically significant.

Monitoring IgE over time in Imported Icelandic Horses

• The researchers continued to monitor the total serum IgE in a cohort of Icelandic horses imported into Switzerland over a period of 3 years.
• High levels of serum IgE were present in all horses at the start of the study but dropped within the first year after import.
• However, total serum IgE remained low in Icelandic horses that remained healthy but rose significantly in those that developed IBDH.

Conclusion

• The high levels of IgE in horses that developed IBDH supports the conclusion that IBDH is a type I hypersensitivity response to insect allergens.
• The data suggests that IBDH in Icelandic horses may have a different pathogenesis from the same condition in other breeds.