At a Glance
Researchers at Colorado State University have developed a novel method for the inactivation of a whole virion particles to produce animal health related vaccines. The use of this methodology may afford a means to rapidly produce vaccine candidates in response to both emergent and existing disease threats. Due to the specificity of the chemistry, the ability to achieve inactivation using this photochemical method may have several significant advantages over the approaches used today which utilize chemical agents such as formalin, Beta propiolactone and ethyleneimine derivatives. This may make possible the production of vaccine candidates with much better immunogen profiles than existing and includes the potential to extend such an approach to agents that may recalcitrant with regard to current technology.
These methods have been utilized in human vaccine candidates, resulting in successful challenge studies in clinically relevant animal models.
This method employs the use of a photochemical (riboflavin or vitamin B2) in combination with UV light in the UVA and UVB wavelength regions to carry out specific nucleic acid alterations through electron transfer chemistry-based processes. The method was originally developed for the treatment of blood products to prevent transfusion transmitted diseases and has been in routine clinical use for prevention of transfusion transmitted viral, bacterial, and parasitic diseases since 2008. The process utilizes a well-established and demonstrated capability of riboflavin and UV light to modify nucleic acid structure primarily through modification of guanine bases in a non-oxygen dependent process utilizing the natural electron donor-acceptor chemistry associated with guanine and riboflavin, respectively.
The process allows for retention of plasma and cell-bound protein structure post treatment to an extent that such products may still be efficacious in functional utilization for transfusion support of patients. Furthermore, this approach has a well-established safety toxicology profile, is non-mutagenic and non-carcinogenic and poses little to no toxicity or disposal risk to facility personnel or the environment. This safety profile has been documented extensively in pre-clinical and clinical programs in human subjects.
Figure 1. Depiction of the general concept of an endogenous photosensitizer such as Riboflavin and UV light to carry out specific changes in nucleic acid
Figure 2. Apparatus used to produce photoinactivated vaccine candidates
The approach was based on the hypothesis that the ability to inactivate virus replication without inducing damage to protein epitopes, could result in the generation of a potent vaccine candidate with intact protein antigen targets comparable to native, live-type virus. Furthermore, such a candidate would be able to induce a potent immune response with relatively low doses of immunogen and thus provide protective immunity against live virus challenge.
Studies have demonstrated the ability of such products made via this method to induce a potent immune response to vaccination. The vaccine response triggered both Th1 and Th2 type immune pathways, leading to generation of neutralizing antibodies and cellular responses capable of protecting vaccinated animals against intranasal challenge. Furthermore, the use of adjuvants was found to boost the levels of neutralizing antibody titers. Non-adjuvanted formulation still provided sufficient protection to prevent viral production and shedding in challenged animals.
- Ability to produce vaccines with high immunogenicity at low immunogen doses
- Vaccine candidates produced using this method are fully attenuated with regard to replication capabilities while maintaining viral protein structural integrity as close to the native virus as possible
- Well-established safety toxicology profile for chemicals and components used in the vaccine manufacturing process, i.e., non-mutagenic and non-carcinogenic materials that pose little to no toxicity or disposal risk to facility personnel or the environment in contrast to conventional methods for producing inactivated vaccine candidates.
- Safety profile of materials and methods has been documented extensively in pre-clinical and clinical programs in human subjects through clinical use of products in blood safety applications dating from 2007 to present.
- Rapid and affordable production of the inactivated vaccine is both practical and cost-effective. Raw material costs and production time is minimal for even bulk production of vaccine candidates.
- Utilizes existing equipment, reagents and disposables that are in routine use for treatment of blood products. Equipment is commercially available and in widespread, global distribution and use.
- Development of vaccines for veterinary uses (e.g., large and small animal, livestock, exotic, etc.)
Last updated: August 2021