Selection of antibody-binding covalent aptamers

Area of Science:

• Biotechnology
• Molecular Biology
• Chemical Biology

Background:

• Aptamers are DNA or RNA molecules with antibody-like binding capabilities.
• Current methods for antibody modification can lack specificity.
• Developing site-specific antibody conjugation methods is crucial for advanced applications.

Purpose of the Study:

• To develop and characterize DNA aptamers capable of covalent conjugation to monoclonal antibodies.
• To create antibody-oligonucleotide conjugates (AOCs) for detection and imaging applications.

Main Methods:

• Modification of a DNA aptamer library with N-hydroxysuccinimide esters.
• Selection of aptamers binding to mouse monoclonal antibodies.
• Characterization of aptamer binding specificity and conjugation conditions.
• Application of aptamers in AOC formation for protein detection and super-resolution imaging.

Main Results:

• Isolation of two distinct DNA aptamer motifs that covalently bind to the Fc region of mouse monoclonal IgG1.
• Demonstrated cross-reactivity with mouse IgG2a and other IgG subtypes.
• Identified a dependence on Cu2+ ions for covalent conjugation, attributed to residual catalyst.
• Successful use of aptamers to form AOCs for HIV p24 detection and actin super-resolution imaging.

Conclusions:

• Introduced a novel method for site-specific modification of native monoclonal antibodies using covalent aptamers.
• The developed aptamers and AOCs show potential for various diagnostic and imaging applications.
• This approach offers a versatile tool for creating custom antibody conjugates.