Among monoclonal antibodies reacting to platelets, some GPIIb/IIIa antibodies have been reported to react to the platelets of different animals.
In this study, we searched for common antigens for platelets of dogs and humans, using 11 monoclonal anti-human-platelet antibodies. By flow cytometry, we examined the reactivity of various monoclonal antibodies to dog platelets. Anti-GPIIb/IIIa antibody NNKY2-11 reacted with about 80%, NNKY2-18 about 50%, CD9 antibody NNKY1-19 about 60%, and MALL13 about 95% of dog platelets, indicating that these monoclonal antibodies recongnize a common antigen in the platelet membranes of dog and human. These anti-GPIIb/IIIa antibodies also inhibited the ADP and collagen aggregation of dog platelets but significantly. When dog platelets were treated with EDTA, the reactivity of the anti-GPIIb/IIIa antibodies decreased significantly. It suggested that the structure of the epitope recognized is dipendent upon Ca++, similar to the human platelet GPIIb/IIIa. However, dog platelets did not show an increase in antibody reactivity upon activation. Autoradiography showed that the antigen recognized by NNKY2-11 on the dog platelet membrane is not exactly the same as GPIIb/IIIa of human platelets. The CD9 antibody MALL13 aggregated dog platelets.
We suggest that these monoclonal antibodies may be useful studying platelet function in dogs.
