Robust Methods for Anti-Oligonucleotide Antibody Generation

Oligonucleotide therapies have gained momentum in the pharmaceutical industry since the approval of Fomivirsen, an anti-sense oligonucleotide therapeutic, in 1998. Oligonucleotides are nucleic acid fragments designed to influence gene products and therefore the biochemical processes within patients. Oligonucleotides often contain one or more structural modifications that increase their stability, uptake, and effectiveness. The variety of therapeutic modes of action increases the value of oligonucleotides, exemplified by success in cell and gene therapies for liver and eye malignancies and in the treatment of cancers. Strategies include gene-specific antisense oligonucleotides to disrupt the transcription of the defective gene; or using siRNA to induce cleavage of the mRNA transcript, disrupting expression of the bad gene. Additionally, different oligonucleotide modifications may be incorporated (e.g. nucleoside fluorination, or to the sugar-phosphate backbone components) with phosphorothioate backbone replacement being the most common.

Oligonucleotide therapeutics is a relatively immature field. Biotech and Pharma companies currently rely on conventional immunoassays as part of the bioanalytical strategy supporting clinical development and this requires the creation of de novo immunogenicity and anti-drug antibody assays to support required safety and quality standards. Critical to the development of these bioanalytical assays are antibody reagents specific to the modified oligonucleotide. Making modified-oligonucleotide-specific antibodies is not trivial, and known problems include poor antigen-immunogenicity and the antibody's ability to differentiate the modified-therapeutic from endogenous molecules. Here we summarize our expertise in developing oligo-specific antibody reagents to a number of different target chemistries. Our methods, including oligonucleotide-antigen preparations and qualification, immunization strategies as well as characterization of highly specific antibodies, provide the bioanalytical tools to support the development of oligo-based therapeutics.