Celltech Therapeutics Limited

Celltech Limited

Andrew Mountain

Raymond John Owens

John Robert Adair

Mark William Bodmer

Geoffrey Thomas Yarranton

David John King

Andrew Neil Weir

Andrew Neil Charles Weir

A method for expressing recombinant molecules in bacterial hosts in a defined medium in the absence of antibiotic selection is disclosed. The method uses an expression vector comprising a regulatable promoter by which the production of foreign proteins may be controlled during the growth phase of the culture, and origin of replication maintaining medium vector copy number and a transcriptional promoter.

Protein expression system

Method for expressing recombinant genes in bacteria in absence of

The present invention provides humanized antibody molecules (HAMs) having specificity for carcinoembryonic antigen (CEA) and having an antigen binding site wherein at least one of the complementarity determining regions (CDRs) of the variable domains is derived from the mouse monoclonal antibody A5B7 (A5B7 MAB) and the remaining immunoglobulin-derived parts of the HAM are derived from a human immunoglobulin. The HAMs may be chimeric humanized antibodies or CDR-grafted humanized antibodies and are preferably produced by recombinant DNA techniques. The HAMs are useful for in vivo diagnosis and therapy.

CDR grafted anti-CEA antibodies and their production

A multivalent antigen-binding protein comprises a first Fv fragment bound to at least one further Fv fragment by a connecting structure which links the Fv fragments to each other but which maintains them spaced apart such that the proteins are capable of binding to adjacent antigenic determinants. Typically the connecting structure comprises a spacing polypeptide sequence, which may be about 3 to 16 amino acids in length, connected to a linkage unit which may be a synthetic chemical linker, e.g., a maleimide linker, or is a polypeptide sequence leading from the spacing sequence. In a particularly preferred embodiment, the multivalent antigen binding protein comprises a VH domain having attached to its C-terminal end a V-C joining sequence and an antibody hinge sequence. Preferably one or more of the Fv fragments is a single chain Fv (scFv). The proteins are preferably prepared by recombinant DNA techniques and are useful for in vivo therapeutic and especially diagnostic applications.

Multivalent antigen-binding proteins

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Wokingham, United Kingdom

Andrew Mountain