Conformational changes in a Vernier zone region: Implications for antibody dual specificity

Area of Science:

• Biochemistry
• Immunology
• Structural Biology

Background:

• Monospecific antibodies dominate therapeutics, but multispecific antibodies show potential for increased efficacy.
• Dual-specific antibodies, binding two antigens with one binding site, represent a promising nonstandard therapeutic approach.
• Understanding the molecular basis of dual specificity is crucial for advancing antibody engineering.

Purpose of the Study:

• To investigate the physicochemical and structural determinants of dual antibody specificity.
• To identify key regions within antibodies responsible for dual-antigen binding.
• To explore the potential of Vernier zone residues in engineering dual-specific antibodies.

Main Methods:

• Physicochemical and structural analysis of six antibodies (two monospecific, four dual-specific).
• Comparison of structural features between monospecific templates and derived dual-specific antibodies.
• Analysis of Vernier zone residue interactions, specifically LV4 and LCDR1 loops.

Main Results:

• Identified clustered Vernier zone residues as critical for acquiring dual specificity.
• Observed significant structural changes and close contact formation between LV4-LCDR1 loops in dual-specific antibodies.
• Demonstrated dual-specific antibodies targeting human epidermal growth factor receptor 2 and vascular endothelial growth factor.

Conclusions:

• Vernier zone residues play an underestimated yet crucial role in conferring dual antibody specificity.
• Structural insights into Vernier zone modifications can guide the engineering of novel dual-specific antibodies.
• Resurrecting the importance of Vernier zone residues offers new avenues for antibody-based therapeutic development.