Monoclonal Antibody Designated T2G1 Reacts With Human Fibrin β-Chain but Not With the Corresponding Chain From Mouse Fibrin

To the Editor: This communication concerns data presented by Tabrizi and coworkers,1 wherein the authors used antibody T2G1 to recognize mouse fibrin β-chain. There is some confusion as to the antibody, since the authors link T2G1 to a different antibody (designated 59D8) used in a separate study.2 Antibody T2G1 was prepared by our group,3 and to the best of our knowledge, no one has ever shown it to be reactive with mouse fibrin. At about the time we identified T2G1, Hui and coworkers4 described several antibodies, including 59D8, that reacted with human fibrin. To evaluate such monoclonals as clot imaging agents, we compared T2G1 and 59D8 and found that both were specific for the new NH2-terminus of fibrin β-chain.5 Matsueda and Margolies6 found that 59D8 also bound dog but not bovine, ovine, or porcine fibrins and speculated that Leu5 in the fibrin β-chain was the structural determinant underlying species specificity. A more recent study showed that antibody 59D8 also reacts with mouse fibrin β-chain.2 In contrast, we had observed that plastic-coated human3 as well as dog and rhesus monkey fibrinogen—after in situ activation with thrombin—bound T2G1, whereas mouse fibrinogen, treated in the same fashion, did not (B.J.K. et al, unpublished data, 1993). The results of Weiler-Guettler and coworkers2 prompted us to reexamine the reactivity of antibody T2G1 with mouse fibrin. The Figure⇓ shows that T2G1 reacts not only with fibrin β-chain made from pure human fibrinogen or clotted plasma but also with several …