A monoclonal antibody which recognises an epitopic region unique to the intact fibrin polymeric structure

Abstract

A hybridoma cell line (MH-1) which produces monoclonal antibody, specific to the fibrin polymeric structure, has been established. The MH-1 antibody is an IgG, (κ light chain) which has a relatively high affinity for crosslinked fibrin (K D=6.7 × 10 −10 M) and a 10-fold lower avidity for non-crosslinked fibrin. The antibody is highly specific for fibrin, and no detectable immunoreactivity with fibrinogen was observed in a direct binding ELISA or in a competition assay using a 500-fold molar excess of fibrinogen. In an in vitro assay, plasma clot uptake of 125I-labelled MH-1 was greater than 70% in both the absence and presence of a plasma milieu. The epitope on fibrin, which the antibody recognises, is destroyed by plasmin digestion and therefore the antibody does not crossreact with any fibrin or fibrinogen degradation products. In addition, the antibody does not react with desAA fibrin or fibrin monomer. Disruption of the tertiary molecular structure of the fibrin polymer by reduction or cyanogen bromide cleavage yielded no immunoreactive fragments. Similarly, no immunoreactivity with the individual α β or γ chains of fibrinogen was detected.