Pegylated Trastuzumab Fragments Acquire an Increased in Vivo Stability but Show a Largely Reduced Affinity for the Target Antigen(466 views)(PDF public264 views) Selis F, Focà G, Sandomenico A, Marra C, Di Mauro C, Jotti GS, Scaramuzza S, Politano A, Sanna R, Ruvo M, Tonon G
Bioker srl-Multimedica Group, c/o Institute of Genetics and
Biophysics, National Research Council (CNR-IGB) via P. Castellino 111,
Institute of Biostructure and Bioimaging, National Research Council (IBB-CNR), via Mezzocannone 16, 80134 Napoli, Italy
Centro Interuniversitario di Ricerca sui Peptidi Bioattivi
(CIRPeB), University of Naples Federico II, via Mezzocannone 16, 80134
Department of Clinical Medicine and Surgery, University of Naples Federico II, 80134 Napoli, Italy
Department of Biomedical, Biotechnological and Translational
Science (S.Bi.Bi.T.), Università di Parma, 43126 Parma, Italy
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Pegylated Trastuzumab Fragments Acquire an Increased in Vivo Stability but Show a Largely Reduced Affinity for the Target Antigen
PEGylation of biomolecules is a major approach to increase blood stream half-life, stability
and solubility of biotherapeutics and to reduce their immunogenicity, aggregation potential and
unspecific interactions with other proteins and tissues. Antibodies have generally long half-lives
due to high molecular mass and stability toward proteases, however their size lowers to some extent
their potential because of a reduced ability to penetrate tissues, especially those of tumor origin.
Fab or otherwise engineered smaller fragments are an alternative but are less stable and are much
less well retained in circulation. We have here investigated the effects of various PEGylations on
the binding properties and
in vivo
half-life of Fab fragments derived from the enzymatic splitting of
Trastuzumab. We find that PEGylation increases the half-life of the molecules but also strongly affects
the ability to recognize the target antigen in a way that is dependent on the extent and position of the
chemical modification. Data thus support the concept that polyethylene glycol (PEG) conjugation on
Trastuzumab Fabs increases half-life but reduces their affinity and this is a fine balance, which must
be carefully considered for the design of strategies based on the use of antibody fragments.
Pegylated Trastuzumab Fragments Acquire an Increased in Vivo Stability but Show a Largely Reduced Affinity for the Target Antigen