Analysis of the V genes coding for a monospecific human antibody to myosinand functional expression of single chain Fv fragments

A monospecific human IgM monoclonal antibody (mAb), reactive,vith myosin fr om human heart, has been obtained by EBV transformation. This mAb mag have a diagnostic potential in the imaging of myocardial necrosis, However, owin g to the fact that the molecular mass of an IgM is 900 kDa, a poor diffusio n and a slow penetration inside necrotic myocytes could reduce its capacity for scintigraphic detection. In order to alleviate these problems, we cons tructed the scFv by cloning the VH and VL domains into the pHOG21 vector. A nalysis of the V genes proved an unmutated configuration shelving that the immortalized B cell issued from the primary IgM repertoire. The expression product in Escherichia coli was a 35 kDa scFv fragment with the antigen-bin ding specificity of the parental mAb. (C) 1999 Federation of European Bioch emical Societies.