Using Synthetic Peptide for Epitope Mapping

DATE: June 7, 2020

Epitope mapping distinguishes antigen areas that fill in as binding regions for antibodies. The overlapping linear peptides derived from the antigen’s primary sequence are often utilized for the epitope screening. And, individual peptides are further divided into small fragments that generally overlap. The subsequent overlapping peptide libraries are then used for several processes – including leaner epitope mapping.

For instance, to map an antibody’s epitope, the overlapping fragments crossing the target sites are assembled in an expression vector. These are then quickly transfected in cells, and the whole-cell lysates accumulate after 48 hours are exposed to Western blot with the antibody. A series of overlapping peptides are also synthesized to further map the site of the fragment. These peptides and lysates from the cells revealing full-length genes are achieved by the dot blot. 

Mapping epitopes precisely and quickly is challenging. That’s because the epitopes, in general, are nonlinear on antigens. Combining and binding two distinct epitopes specifically into single molecules considerably boost the immunotherapeutic properties of monoclonal antibodies. 

The antigen-antibody interaction can be studied using several tools, mentioned below. 

Use Multiple Antigenic Peptides (MAPs) as immunogens – MAPS are peptides that are branched synthetically. Lys residues are mainly used as scaffolding core that helps the formation of eight branches with the same or varying peptide sequences. For instance, the goal is to combine different epitopes from varied virus proteins in a particular, single unit. The epitopes that show the right prediction of antigenicity and are conserved in most serotypes are preferred to assemble as the MAP.

Optimizing enzyme substrates and creating high-affinity protein ligands using screening combinatorial peptide libraries – A vital biological application of custom peptide libraries is a depiction of binding events occurring in between specific protein and its peptide ligands. To map and validate epitopes, a series of overlapping peptides, Alanine peptide scanning, Truncation peptide, Positional Peptide, or Scrambled peptide are mainly used. These can also be used for the characterization of therapeutic antibodies and neutralizing antibody actions in vitro. 

Connect with RS Synthesis to get peptide library services for epitope mapping studies and vaccine research.