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

The research investigated the cross-reactivity of 155 monoclonal antibodies (mAbs) with equine leukocytes, as part of a larger screening process to improve understanding of equine immunology. This study resulted in the identification of 16 mAbs showing similar staining patterns to human leukocytes, establishing the potential for a “cross-reactivity” approach.

Screening of Monoclonal Antibodies with Equine Leukocytes

• The study tested for the reactivity of 155 monoclonal antibodies (mAbs) with equine leukocytes. The mAbs were previously not tested in the HLDA8 animal homologues section. The aim of the research was to find antibodies that could function similarly in horses as they do in humans.
• Flow cytometric analysis was used as the screening method. Flow cytometry is a technology that simultaneously measures and analyses multiple physical characteristics of single particles — in this case, leukocytes, which are a type of white blood cell.

Results of the Screening

• The additional screening identified various mAbs with different reactivity patterns. Sixteen mAbs showed positive staining with a pattern homologous to that seen in human leukocytes.
• Further findings indicated one mAb with weak reactivity, eleven mAbs with positive reactivity but likely not valuable staining, twelve mAbs with an alternate staining pattern, two mAbs with questionable variable staining, thirteen mAbs with weak-positive expression and alternate pattern, and seventy-eight were negative mAbs.
• In 23 cases, more appropriate target cells such as thymocytes or stem cells were not available for the screening.

Significance and Implication of Findings

• The results support the “cross-reactivity” approach for equine immunology. This approach looks at the common immune responses between species and could greatly benefit equine health research.
• These findings can be used to advance the understanding of equine immunology which can be applied in creating better diagnostic tools and treatments for diseases that affect equines.