Catalytic antibodies and a method of producing same

A growth factor precursor comprising a recombinant polypeptide chain or a molecule having modular peptide components or a synthetic equivalent thereof wherein said polypeptide chain or modular peptide molecule comprises at least one B cell surface molecule binding portion, at least one T cell surface molecule binding portion capable of providing T cell dependent help to a B cell, an antigen cleavable by a catalytic antibody and a peptide portion comprising domains from both a variable heavy chain and a variable light chain of an immunoglobulin and wherein said variable heavy chain and variable light chain domains in the growth factor precursor associate together by intra- and/or inter-domain bonding and substantially prevent the at least one B cell surface molecule binding portion from interacting with a B cell surface molecule such that upon cleavage of said antigen by a catalytic antibody, the peptide comprising said variable heavy chain and variable light chain domain permits the at least one B cell surface molecule binding portion to interact with a B cell surface molecule wherein if said growth factor precursor comprises a single B cell surface molecule binding portion, then the growth factor precursor further comprises a multimerising inducing element.

A method for producing catalytic antibodies to a specific antigen, said method comprising administering to an animal an effective amount of a growth factor precursor comprising an antigen capable of interacting with a B cell bound catalytic antibody said antigen fused to a B cell surface molecule binding portion for a time and under conditions for said antigen to be cleaved and for the remainder of the molecule to induce B cell mitogenesis.

A composition comprising the recombinant or synthetic growth factor precursor thereof according to any one of claims I or 2 and one or more pharmaceutical carriers and/or diluents.