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Published on: September 18, 2014
Development of Nonaggregating Poly-A Tailed Immunostimulatory A/D Type CpG Oligodeoxynucleotides Applicable for
Taiki Aoshi1, Yasunari Haseda2, Kouji Kobiyama3
1Laboratory of Adjuvant Innovation, National Institute of Biomedical Innovation, Health and Nutrition, Ibaraki, Osaka 567-0085, Japan ; Laboratory of Vaccine Science, Immunology Frontier Research Center (iFReC), Osaka University, Suita, Osaka 565-0871, Japan ; Vaccine Dynamics Project, BIKEN Innovative Vaccine Research Alliance Laboratories, Research Institute for Microbial Diseases (RIMD), Osaka University, Suita, Osaka 565-0871, Japan.
Abstract:
Immunostimulatory CpG ODNs have been developed and utilized as TLR9-dependent innate immune activators and vaccine adjuvants. Four different types of immunostimulatory CpG ODNs (A/D, B/K, C, and P type) have been reported. A/D type ODNs are characterized by high IFN-α production but intrinsically form aggregates, hindering its good manufacturing practice grade preparation. In this study, we developed several D35-derived ODNs (a commonly used A/D type ODN), which were modified with the addition of a phosphorothioate polynucleotide tail (such as dAs40), and examined their physical properties, solubility in saline, immunostimulatory activity on human PBMCs, and vaccine adjuvant potential in monkeys. We found that two modified ODNs including D35-dAs40 and D35core-dAs40 were immunostimulatory, similar to original D35 in human PBMCs, resulting in high IFN-α secretion in a dose-dependent manner. Physical property analysis by dynamic light scattering revealed that both D35-dAs40 and D35core-dAs40 did not form aggregates in saline, which is currently impossible for the original D35. Furthermore, D35-dAs40 and D35core-dAs40 worked as better vaccine adjuvant in monkeys. These results suggested that D35-dAs40 and D35core-dAs40 are two promising prototypes of nonaggregating A/D type ODN with advantages of ease of drug preparation for clinical applications as vaccine adjuvants or IFN-α inducing immunomodifiers.
Insights
Modified CpG oligonucleotides (ODNs) overcome aggregation issues, maintaining potent immune activation and vaccine adjuvant capabilities. These non-aggregating A/D type ODNs offer improved manufacturing for clinical applications.
Area of Science:
- Immunology
- Vaccinology
- Oligonucleotide Therapeutics
Background:
- Immunostimulatory CpG oligonucleotides (ODNs) are Toll-like receptor 9 (TLR9)-dependent innate immune activators and vaccine adjuvants.
- A/D type CpG ODNs induce high interferon-alpha (IFN-α) but form aggregates, complicating manufacturing.
- Existing A/D type ODNs face challenges in good manufacturing practice (GMP) preparation due to aggregation.
Purpose of the Study:
- To develop non-aggregating A/D type CpG ODNs with retained immunostimulatory and adjuvant properties.
- To evaluate modified D35-derived ODNs for physical properties, solubility, immune activity, and vaccine adjuvant potential.
Main Methods:
- Modification of D35-derived ODNs with phosphorothioate polynucleotide tails (e.g., dAs40).
- Assessment of physical properties using dynamic light scattering.
- Evaluation of immunostimulatory activity in human peripheral blood mononuclear cells (PBMCs) and vaccine adjuvant potential in non-human primates.
Main Results:
- Two modified ODNs, D35-dAs40 and D35core-dAs40, demonstrated potent IFN-α secretion in human PBMCs, similar to the original D35.
- Dynamic light scattering confirmed that D35-dAs40 and D35core-dAs40 do not form aggregates in saline.
- Both modified ODNs exhibited enhanced vaccine adjuvant efficacy in non-human primates compared to controls.
Conclusions:
- D35-dAs40 and D35core-dAs40 are promising non-aggregating A/D type CpG ODN prototypes.
- These modified ODNs facilitate easier drug preparation for clinical applications.
- They hold potential as vaccine adjuvants or IFN-α-inducing immunomodifiers.
