Monoclonal antibodies specific for poly(dG) X poly(dC) and poly(dG) X poly(dm5C)

Area of Science:

• Immunology
• Molecular Biology
• Biochemistry

Background:

• Most B-form duplex DNA is non-immunogenic.
• Poly(dG) X poly(dC) is an exception, eliciting a strong immune response despite its conventional structure.

Purpose of the Study:

• To investigate the specific features of DNA recognized by the immune system.
• To characterize monoclonal antibodies binding to immunogenic DNA polymers.

Main Methods:

• Generation of monoclonal antibodies (Jel 72 and Jel 68) against poly(dG) X poly(dC).
• Testing antibody binding against various synthetic DNA duplexes and natural DNA (phage XP-12).
• Inhibition assays using ethidium and DNA denaturation to confirm antibody specificity.

Main Results:

• Jel 72 (IgG) binds specifically to poly(dG) X poly(dC).
• Jel 68 (IgM) shows a stronger affinity for poly(dG) X poly(dm5C) than poly(dG) X poly(dC).
• Neither antibody recognized other synthetic DNA duplexes or B/Z-form DNA variants.

Conclusions:

• The antibodies recognize specific structural features of DNA, not single- or multi-stranded forms.
• The results suggest that (dG)n X (dm5C)n sequences in DNA possess unique, recognizable conformations.