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Christelle Souriau

Publications and source records attributed to Christelle Souriau.

5 recordsLinked to original sources
PubMed2005

New binding specificities derived from Min-23, a small cystine-stabilized peptidic scaffold.

The randomization of both internal and surface residues in small protein domains followed by selection from a display library is emerging as a powerful strategy to obtain novel binding specificities. Small and stable scaffold motifs observed in disulfide-rich proteins are attractive because they are small, stable, and accessible to chemical synthesis. The elementary structural motif found in the squash trypsin inhibitor EETI-II (Ecballium elaterium trypsin inhibitor) is the cystine stabilized beta-sheet (CSB) motif, found in nearly 50% of all known small disulfide-rich protein families. We have used Min-23, a short 23-residue peptide containing the CSB motif and shown to be a stable autonomous folding unit and one of the smallest scaffolds described to date, as a scaffold for selection of new binding ligands. We demonstrate that the core CSB motif in Min-23 is permissive to loop insertion, using peptide epitopes from hemagglutinin (HA) and Gla-protein (E). A phage library of more than 10(8) different clones has been constructed by insertion of a randomized sequence on a beta-turn of the Min-23 peptide. The selection of this library on a variety of 7 different targets allowed the isolation of 21 new specific binders, confirming the potential of Min-23 as a scaffold for the development of new ligands. The derived library is able to provide a wide range of novel compounds with possible applications in various biological and pharmaceutical areas.

Amino Acid Motifs↗
PubMed2004

Human antibody fragments specific for the epidermal growth factor receptor selected from large non-immunised phage display libraries.

Antibodies to EGFR have been shown to display anti-tumour effects mediated in part by inhibition of cellular proliferation and angiogenesis, and by enhancement of apoptosis. Humanised antibodies are preferred for clinical use to reduce complications with HAMA and HAHA responses frequently seen with murine and chimaeric antibodies. We have used depletion and subtractive selection strategies on cells expressing the EGFR to sample two large antibody fragment phage display libraries for the presence of human antibodies which are specific for the EGFR. Four Fab fragments and six scFv fragments were identified, with affinities of up to 2.2nM as determined by BIAcore analysis using global fitting of the binding curves to obtain the individual rate constants (ka and kd). This overall approach offers a generic screening method for the identification of growth factor specific antibodies and antibody fragments from large expression libraries and has potential for the rapid development of new therapeutic and diagnostic reagents.

Apoptosis↗
PubMed2003

Recombinant antibodies for cancer diagnosis and therapy.

Recombinant antibodies currently represent over 30% of biopharmaceuticals in clinical trials, highlighted by the recent Food and Drug Administration (FDA) approvals of Zevalin(TM) (ibritumomab-tiuxetan; IDEC Pharmaceuticals, San Dieago, CA, USA) for cancer radioimmunotherapy and Humira(TM) (adalimumab; Abbott Laboratories, IL, USA) for rheumatoid arthritis. Together, these FDA approvals have excited the biotechnology industry, particularly since sales of recombinant antibodies are increasing rapidly to a predicted US dollar 4 billion per annum worldwide in 2003. To date, 10 engineered therapeutic antibodies have gained FDA approval and many others are in Phase III trials. Many recent FDA-approved antibodies are simple molecular designs that have taken 10 years to be developed into effective therapeutic reagents. Emerging new technologies have created a vast range of recombinant, antibody-based reagents, which specifically target clinical biomarkers of disease. Radiolabelling of antibodies has increased their potential for cancer imaging and targeting. Recombinant antibodies have also been reduced in size and rebuilt into multivalent molecules for higher affinity. In addition, antibodies have been fused with many molecules, including toxins, enzymes, drugs and viruses, for prodrug therapy, cancer treatment and gene delivery. Recombinant antibody technology has enabled clever manipulations in the construction of complex in vitro libraries for the selection of high-affinity reagents against refractory targets. Furthermore, innovative affinity maturation methods have been developed which enable rapid selection of extremely high-affinity reagents. This review focuses on developments in the last 12 months and describes the latest developments in the design, production and clinical use of recombinant antibodies for cancer diagnosis and therapy.

Animals↗
PubMed2002

Role of the N-terminus of epidermal growth factor in ErbB-2/ErbB-3 binding studied by phage display.

Epidermal growth factor (EGF) binds with high affinity to the EGF receptor, also known as ErbB-1, but upon replacement of the N-terminal linear region by neuregulin (NRG) 1 or transforming growth factor (TGF) alpha sequences it gains in addition high affinity for ErbB-2/ErbB-3 heterodimers. However, these chimeras weakly bind to ErbB-3 alone. To further dissect the ligand binding selectivity of the ErbB network, we have applied the phage display technique to examine the role of the linear N-terminal region in EGF for interaction with ErbB-2/ErbB-3 heterodimers. A library of EGF variants was constructed in which residues 2, 3, and 4 were randomly mutated, followed by selection for binding to intact MDA-MB-453 cells that overexpress ErbB-2 and ErbB-3 but lack ErbB-1. Analysis of the selected phage EGF variants revealed clones with high binding affinity to ErbB-2/ErbB-3 while maintaining high affinity to ErbB-1. In these variants, Trp (or alternatively His) was almost exclusively present at position 2, while specific combinations of hydrophobic, basic, and small residues were found at positions 3 and 4. The mitogenic activity of the phage EGF variants corresponded with their relative binding affinity. Two of the selected EGF variants, EGF/WVS and EGF/WRS, were further characterized as recombinant proteins. In contrast to previously characterized chimeras of EGF with NRG-1 or TGF-alpha, these variants did not only show high binding affinity for ErbB-2/ErbB-3 heterodimers but also for ErbB-3 alone. These data show that the linear N-terminal region of EGF-like growth factors is directly involved in binding to ErbB-3.

Amino Acid Sequence↗