Definition of 15 equine leucocyte antigens.

The research article describes the identification of 15 equine leucocyte antigens – proteins present on the surface of horse’s white blood cells – through a series of tests using horses which had developed antibodies during pregnancy or via specific immunisation.

Methodology

• The study used absorption and titration analysis of alloantisera. Alloantisera are the antibodies produced by an individual in response to exposure to foreign antigens, in this case, through pregnancy or planned experimental immunization.
• The key antibodies were then tested against cells from 90 unrelated horses and members of eight separate horse families.

Findings

• Based on the data derived from horse families, the researchers concluded that 13 out of the 15 equine leucocyte antigens were encoded by a single specific genetic locus, referred to as the “first locus.”
• Another antigen (Eq 14) was determined to be controlled by a second genetic location that is linked to the first one, referred to as the “second locus.”
• The final antigen (Eq 7) was found to be controlled by a third genetic location, distinct from the first two loci, referred to as the “third locus.”

Additional Tests

• Supplementary tests performed on cells from unrelated horses identified a “supertypic” relationship between two first locus antigens, Eq 16 and Eq17, meaning these antigens were overarching, or common, across several smaller antigen groups of the first locus.
• Furthermore, the investigation found no individual horse was found to carry more than two of the first locus antigens, excluding those two supertypic antigens.

The research provides insight into the diversity and genetic coding of equine leucocyte antigens, which is key for understanding horse immunity and could potentially lead to advancements in equine healthcare.