Non-HLDA8 animal homologue section anti-leukocyte mAbs tested for reactivity with equine leukocytes

In addition to the 379 monoclonal antibodies (mAbs) tested in the animal homologues section of HLDA8, another 155 mAbs were screened at the Institute for Zoo and Wildlife Research, Berlin for cross-reactivity with equine leukocytes. For this purpose, one colour flow-cytometric analysis was performed as screening test. This additional screening indicated further 16 mAbs as positive with staining homologous to human pattern, 1 mAb with weak (positive) reactivity, 11 mAbs with positive, but likely not valuable staining, 12 mAbs with alternate expression pattern from that expected from human immunology, 2 mAbs with questionable variable staining, 13 mAbs with weak-positive expression and alternate pattern, and 78 negative mAbs. In 23 cases, more appropriate target cells, such as thymocytes or stem cells, were not available for screening. The results support and add to the value of the "cross-reactivity" approach for equine immunology.