Cross‐Reactivity of Rabbit Anti‐Bovine Thrombin IgGs with a Human Plasma Derived Thrombin Preparation (Evithrom ™ )

Studies have shown that rabbit anti‐bovine thrombin IgGs cross‐react with human alpha‐thrombin and a recombinant version of human thrombin (Recothrom ™ ). This study characterized the cross‐reactivity of anti‐bovine thrombin antibodies with a human plasma‐derived topical thrombin preparation (Evithrom ™ ). Gel electrophoresis revealed that in addition to a human α‐thrombin protein band, Evithrom ™ also contained a large amount of human albumin and a few faint high‐molecular weight bands which were absent in bovine thrombin, human α‐thrombin, human γ‐thrombin and Recothrom ™ . Western blotting results demonstrated no cross‐reactivity with Evithrom ™ when anti‐bovine crude thrombin IgGs and thrombin 4B IgGs were used. However, Evithrom ™ was recognized by rabbit anti‐bovine thrombin 4A IgG. Furthermore, the results revealed the cross‐reactivity of anti‐bovine thrombin 4A IgG with Evithrom ™ was time‐dependent. These results indicate that besides human α‐thrombin and Recothrom ™ , rabbit anti‐bovine thrombin IgGs can also cross‐react with Evithrom ™ suggesting that human antibodies against bovine thrombin may also cross‐react with human thrombin as well as human recombinant thrombin. Thus, the use of Evithrom ™ and RecothromTM may not be recommended in patients who have been previously treated with/exposed to bovine thrombin preparations.