Specificity of a monoclonal antibody for the NH2-terminal region of fibrin.

A monoclonal antibody (MAb/T2G1s) was prepared by fusion using spleen cells from mice immunized with the NH2-terminal CNBr fragment of human fibrin II, the so-called (T)N-DSK [(A alpha 17-51, B beta 15-118, gamma 1-78)2]. In competition experiments, this antibody reacted with (T)N-DSK as well as peptide B beta 15-42 which can be obtained from (T)N-DSK by digestion with plasmin. Little or no reaction was observed with intact fibrinogen, the NH2-terminal CNBr fragments from fibrinogen (N-DSK) or fibrin I [(B)N-DSK], respectively, as well as peptide B beta 1-42. These results suggest that MAb/T2G1s is directed to an epitope on the B beta chain in fibrin II but not in fibrinogen or fibrin I. As such, MAb/T2G1s differs completely from another antibody (MAb/1-8C6)--also specific for the NH2-terminal region of the B beta chain--which was recently described [Kudryk et al. (1983) Molec. Immun. 20, 1191-1200].