Abstract: Bis-maleimido cross-linking reagents join labelled antibodies having at least one sulphide interchain bridge. The conjugates have an enhanced binding capacity and have good blood clearance in vivo. The conjugates are of use in the diagnosis and therapy of tumors and may be prepared by reaction of the cross-linking reagent with the antibody.

Abstract: Cross-linked labelled antibody conjugates are described which have at least one non-disulphide interchain bridge. The bridge may be the residue of a homo- or heterofunctional cross-linking reagent, and is located away from the antigen binding domains of the antibody. The antibody conjugates have an enhanced binding capacity and in vivo have good blood clearance and, in the presence of a tumour high tumour: blood and tumour: bone ratios. The conjugates are of use in the diagnosis and therapy of e.g. tumours and may be prepared by reaction of a cross-linking reagent with an antibody.

Abstract: A process for the production of a fusion protein comprising an active portion of a chloramphenicol acetyltransferase (CAT) protein and a polypeptide. The fusion protein may be purified using CAT substrate affinity chromatography. The eucaryotic polypeptide may be calcitonin or a dervative thereof such as calcitonin-glycine. Other polypeptides described include enzymes such as chymosin, prochymosin and preprochymosin, hormones such as ACTH, insulins, and growth hormones and antigenic polypetides such as foot and mouth disease virus antigenic polypetide. The fusion protein may be cleaved at a site susceptible to selective enzymic or chemical cleavage to produce free polypeptide. The fusion protein may be used as an immunogen.