Tailoring of pharmacokinetic profile

A number of different approaches may be used in order to alter a protein s pharmacokinetic profile. This can be desirable in order to achieve a predefined therapeutic goal, such as generating a faster-or slower-acting product, lengthening a product s serum half-life or altering a product s tissue 

Based on the above principles, it might be assumed that a therapeutic protein obtained by direct extraction from human sources (e.g. some antibody preparations) or produced via recombinant expression of a human gene/cDNA sequence (e.g. recombinant human hormones or cytokines) would be non-immunogenic in humans whereas foreign therapeutic proteins (e.g. non-engineered monoclonal antibodies) would stimulate a human immune response. This general principle holds in many cases, but not all. So why do therapeutic proteins of human amino acid sequences have the potential to trigger an immune response Potential reasons can include  

A number of approaches may be adopted in an attempt to reduce or eliminate protein im-munogenicity. Protein engineering (Chapter 3), for example, has been employed to humanize monoclonal antibodies (Chapter 13). An alternative approach entails the covalent attachment of polyethylene glycol (PEG) to the protein backbone. This can potentially shield immunogenic epitopes upon the protein from the immune system. 

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