Neutralizing epitopes of surface glycoproteins are poorly immunogenic and carbohydrates-based immunogens are generally less effective in generation of long-lasting antibody responses. Therefore, proteins mimicking glycan/peptide epitopes recognized by virus neutralizing antibodies represent a valuable alternative for the development of non-cognate protein ligands as potential preventative vaccine components. Highly complex combinatorial libraries derived from scaffolds of small and robust protein domains represent a powerful tool for the identification of protein binders mimicking surface glycopeptide epitopes of viruses or bacteria that are recognized by broadly neutralizing antibodies. We use our own concept of a highly complex combinatorial library derived from scaffold of 46 amino acid albumin-binding domain (ABD) and, in combination with ribosome display, we target broadly neutralizing antibody (bNAb) IgG to identify unique binding candidates recognizing paratopes of the selected bNabs. In our proof-of-concept study we identified binders called VRA proteins that mimic gp120 epitope of VRC01 bNAb. The generation of other noncognate proteins ligands will be also presented as well as their potential for HIV-1 vaccine development.
Petr Maly is head of Laboratory of Ligand Engineering at the Institute of Biotechnology, Czech Academy of Sciences in Vestec, Czech Republic. He studied at Department of Biochemistry, Faculty of Science, Charles University in Prague, Czech Republic (1980-1985) and completed doctorate at the Institute of Molecular Genetics ASCR (IMG) in Prague. He spent postdoctoral fellowship (1992-1995) at Department of Pathology and Howard Hughes Medical Institute, The University of Michigan Medical School, Ann Arbor, USA, in the laboratory of Prof. John B. Lowe where he published several substantial papers related to in vivo role of mammalian glycosyltransferases. Since 1998 to 2005 he was a research group leader at the IMG in Prague. As a visiting scientist he also worked at Department of Biochemistry and Molecular Biology, College of Medicine, University of Oklahoma, USA. He also was participating investigator of Consortium for Functional Glycomics (USA, 2001–2008) and Member of Editorial Board (2001-2005) and Editor (since 2003) of the Czech journal “Biologicke listy” (Biological Letters). Since 2008, he has been working on the development of combinatorial protein libraries derived from small protein scaffolds, and high-affinity protein binders with therapeutic and diagnostic potential.