Molecular Recognition and Advances in Antibody Design and Antigenic Peptide Targeting

Epitope Mapping of Monoclonal Antibodies to Calreticulin Reveals That Charged Amino Acids Are Essential for Antibody Binding

Calreticulin is a chaperone protein, which is associated with myeloproliferative diseases. In this study, we used resin-bound peptides to characterize two monoclonal antibodies (mAbs) directed to calreticulin, mAb FMC 75 and mAb 16, which both have significantly contributed to understanding the biological function of calreticulin. The antigenicity of the resin-bound peptides was determined by modified enzyme-linked immunosorbent assay. Specific binding was determined to an 8-mer epitope located in the N-terminal (amino acids 34–41) and to a 12-mer peptide located in the C-terminal (amino acids 362–373). Using truncated peptides, the epitopes were identified as TSRWIESK and DEEQRLKEEED for mAb FMC 75 and mAb 16, respectively, where, especially the charged amino acids, were found to have a central role for a stable binding. Further studies indicated that the epitope of mAb FMC 75 is assessable in the oligomeric structure of calreticulin, making this epitope a potential therapeutic target.

Novel GLP-1/anti-apolipoprotein B bifunctional fusion protein alleviates diabetes and diabetic complications in combination with low-intensity ultrasound

AIMS

To engineer and screen a novel GLP-1/anti-apolipoprotein B (apoB) bifunctional fusion protein with therapeutic potential on alleviating diabetes and diabetic complication in combination with low-intensity ultrasound.

MAIN METHODS

Anti-apoB antibodies were screened by phage display technology and further fused to mutated GLP-1 (7-37) via light or heavy fusion to generate bifunctional fusion protein (termed aBG). The optimal design of aBG fusion protein was further confirmed by in vitro epitope competition assay and cAMP accumulation assay. Subsequently, chronic study in DIO mice were subjected to assess the long-term efficacy of screened fusion protein.

KEY FINDINGS

The selected GLP-1/anti-apoB fusion protein, aBG-8, exerted either the highest binding affinities for GLP-1R and apoB, or the greatest LDL-C uptake capacity and GLP-1R activation activity. After 60-day treatment in DIO mice, aBG-8 was proved to exert the promising improvement on hyperglycemia, hyperlipidemia, and obesity in DIO mice. Furthermore, combined therapy of aBG-8 and low-intensity ultrasound could accelerate skin wound closure in diabetic mice.

SIGNIFICANCE

A novel long-lasting bifunctional fusion molecule, aBG-8, was designed with the enormous potential on alleviating diabetes and diabetic complications in combination with low-intensity ultrasound.