Base-specific binding of adenosine antibodies to double-stranded DNA

Area of Science:

• Immunology
• Molecular Biology
• Biochemistry

Background:

• Antibodies against adenosine were previously thought to bind only to single-stranded DNA (ssDNA).
• This limited understanding potentially overlooked interactions with double-stranded DNA (dsDNA).

Purpose of the Study:

• To investigate the binding capabilities of anti-adenosine antibodies with both ssDNA and dsDNA.
• To determine if anti-adenosine antibodies exhibit cross-reactivity between ssDNA and dsDNA.

Main Methods:

• Avidin-biotin microELISA for sensitive antibody-DNA binding detection.
• Homologous hapten inhibition assay to confirm binding specificity.
• Gel retardation assay to assess antibody interaction with plasmid DNA topoisomers.
• Analysis of differential binding to DNA restriction fragments.

Main Results:

• Anti-adenosine antibodies demonstrated specific binding to dsDNA, contrary to prior reports.
• Binding to dsDNA was confirmed as specific through homologous hapten inhibition.
• Distinct antibody populations were identified for ssDNA and dsDNA binding, showing no cross-reactivity.
• Antibodies interacted with plasmid DNA topoisomers and showed differential binding to dsDNA fragments, indicating accessible adenosine residues.

Conclusions:

• Anti-adenosine antibodies can bind to dsDNA, expanding their known reactivity profile.
• The study identified separate antibody populations for ssDNA and dsDNA, refuting cross-reactivity.
• Accessible adenosine residues within dsDNA structures are recognized by these antibodies.