Equine neonatal isoerthrolysis (ENI) caused by incompatibilty of blood group alloantigens between a mare and foal has been detected by the indirect antiglobulin test (coombs test) with polyclonal anti-horse γ-globulinan tibody (pAb). However, since this pAb recognizes not only the incompatible antibodies causing ENI (ENI-causing antibody), but other antibodies specific for blood group as specific antigens, the positivity for antibodies in mare serum becomes higher in routine testing.
Although newborn foals of positive mares have been prevented from developing serious icterus diseases by withholding the colostrum for a certain period of time, failure of passive antibody transfer (FPT) is a problem. Accordingly, monoclonalanti-horser-globulinantibodies(MonoclonalAbs) with higher specificity for the ENI-causing antibodies were developed by a cell fusion technique.
Forty cell lines which produce Monoclonal Abs specific to horse r-globulin were cloned. The Monoclonal Abs from 19 of these cell lines could specifically hemagglutinate the erthrocytes sensitized with the ENI-causing antibodies. The following panel names were given to the 19 Monoclonal Abs : TS-1-TS-5, TS-8-TS-12, A-1-A-3 and G-1-G-6, respectively. The panel of Monoclonal Abs which showed the strongest affinity for the ENI-causing antibodies were TS-4, TS-10, A-1, A-2 and G -1. As a result of clinical testing to prevent ENI in the past three years, the positive rate for mares in the coombs test with Monoclonal Abs (Monoclonal Ab reagents mixed with TS-4 and TS-10 panels) has been significantly decreased in comparison with the results by pAb. These Monoclonal Abs are available for prohylactic for ENI