Preliminary Note on the Preparation of Non-toxic Shiga Dysentery Vaccines by Irradiation with Soft X-rays

Select Whole-Cell Biofilm-Based Immunogens Protect against a Virulent Staphylococcus Isolate in a Stringent Implant Model of Infection

Many microbes of concern to human health remain without vaccines. We have developed a whole-microbe inactivation technology that enables us to rapidly inactivate large quantities of a pathogen while retaining epitopes that were destroyed by previous inactivation methods. The method that we call UVC-MDP inactivation can be used to make whole-cell vaccines with increased potency. We and others are exploring the possibility of using improved irradiation-inactivation technologies to develop whole-cell vaccines for numerous antibiotic-resistant microbes. Here, we apply UVC-MDP to produce candidate MRSA vaccines which we test in a stringent tibia implant model of infection challenged with a virulent MSRA strain. We report high levels of clearance in the model and observe a pattern of protection that correlates with the immunogen protein profile used for vaccination.

Advances in Irradiated Livestock Vaccine Research and Production Addressing the Unmet Needs for Farmers and Veterinary Services in FAO/IAEA Member States

The Animal Production and Health section (APH) of the Joint FAO/IAEA Centre of Nuclear Techniques in Food and Agriculture at the International Atomic Energy Agency has over the last 58 years provided technical and scientific support to more than 100 countries through co-ordinated research activities and technical co-operation projects in peaceful uses of nuclear technologies. A key component of this support has been the development of irradiated vaccines targeting diseases that are endemic to participating countries. APH laboratories has over the last decade developed new techniques and has put in place a framework that allows researchers from participating member states to develop relevant vaccines targeting local diseases while using irradiation as a tool for improving livestock resources.

Ionizing Radiation Technologies for Vaccine Development - A Mini Review

Given the current pandemic the world is struggling with, there is an urgent need to continually improve vaccine technologies. Ionizing radiation technology has a long history in the development of vaccines, dating back to the mid-20^th century. Ionizing radiation technology is a highly versatile technology that has a variety of commercial applications around the world. This brief review summarizes the core technology, the overall effects of ionizing radiation on bacterial cells and reviews vaccine development efforts using ionizing technologies, namely gamma radiation, electron beam, and X-rays.

Radiation-Inactivated Acinetobacter baumannii Vaccine Candidates

Acinetobacter baumannii is a bacterial pathogen that is often multidrug-resistant (MDR) and causes a range of life-threatening illnesses, including pneumonia, septicemia, and wound infections. Some antibiotic treatments can reduce mortality if dosed early enough before an infection progresses, but there are few other treatment options when it comes to MDR-infection. Although several prophylactic strategies have been assessed, no vaccine candidates have advanced to clinical trials or have been approved. Herein, we rapidly produced protective whole-cell immunogens from planktonic and biofilm-like cultures of A. baumannii, strain AB5075 grown using a variety of methods. After selecting a panel of five cultures based on distinct protein profiles, replicative activity was extinguished by exposure to 10 kGy gamma radiation in the presence of a Deinococcus antioxidant complex composed of manganous (Mn²⁺) ions, a decapeptide, and orthophosphate. Mn²⁺ antioxidants prevent hydroxylation and carbonylation of irradiated proteins, but do not protect nucleic acids, yielding replication-deficient immunogenic A. baumannii vaccine candidates. Mice were immunized and boosted twice with 1.0 × 10⁷ irradiated bacterial cells and then challenged intranasally with AB5075 using two mouse models. Planktonic cultures grown for 16 h in rich media and biofilm cultures grown in static cultures underneath minimal (M9) media stimulated immunity that led to 80–100% protection.

X-ray inactivation of RNA viruses without loss of biological characteristics

In the event of an unpredictable viral outbreak requiring high/maximum biosafety containment facilities (i.e. BSL3 and BSL4), X-ray irradiation has the potential to relieve pressures on conventional diagnostic bottlenecks and expediate work at lower containment. Guided by Monte Carlo modelling and in vitro 1-log₁₀ decimal-reduction value (D-value) predictions, the X-ray photon energies required for the effective inactivation of zoonotic viruses belonging to the medically important families of Flaviviridae, Nairoviridae, Phenuiviridae and Togaviridae are demonstrated. Specifically, it is shown that an optimized irradiation approach is attractive for use in a multitude of downstream detection and functional assays, as it preserves key biochemical and immunological properties. This study provides evidence that X-ray irradiation can support emergency preparedness, outbreak response and front-line diagnostics in a safe, reproducible and scalable manner pertinent to operations that are otherwise restricted to higher containment BSL3 or BSL4 laboratories.

Electron-Beam-Inactivated Vaccine Against Salmonella Enteritidis Colonization in Molting Hens

Electron-beam (eBeam) irradiation technology has a variety of applications in modern society. The underlying hypothesis was that eBeam-inactivated Salmonella enterica serovar Enteritidis (SE) cells can serve as a vaccine to control SE colonization and shedding in poultry birds. An eBeam dose of 2.5 kGy (kilograys) was used to inactivate a high-titer (10(8) colony-forming units [CFU]) preparation of SE cells. Microscopic studies revealed that the irradiation did not damage the bacterial cell membranes. The vaccine efficacy was evaluated by administering the eBeam-killed SE cells intramuscularly (1 x 10(6) CFU/bird) into 50-wk-old single comb white leghorn hens. On day 14 postvaccination, the hens were challenged orally with live SE cells (1 x 10(9) CFU) and SE colonization of liver, spleen, ceca, and ovaries determined on day 23. Blood samples were collected on days 0, 14, and 23 postvaccination and the sera were analyzed to quantify SE-specific IgG titers. The vaccinated chickens exhibited significantly (P < 0.0001) higher SE-specific IgG antibody responses and reduced SE ceca colonization (1.46 ± 0.39 logi10 CFU/g) compared to nonvaccinated birds (5.32 ± 0.32 log10 CFU/g). They also exhibited significantly lower SE colonization of the ovaries (1/30), spleen (3/30), liver (4/30), and ceca (7/30) compared to nonvaccinated birds. These results provide empirical evidence that eBeam-based SE vaccines are immunogenic and are capable of protecting chickens against SE colonization. The advantages of eBeam-based vaccine technology are that it is nonthermal, avoids the use of formalin, and can be used to generate inactivated vaccines rapidly to address strain-specific infections in farms or flocks.

Preserving immunogenicity of lethally irradiated viral and bacterial vaccine epitopes using a radio- protective Mn2+-Peptide complex from Deinococcus

Although pathogen inactivation by γ-radiation is an attractive approach for whole-organism vaccine development, radiation doses required to ensure sterility also destroy immunogenic protein epitopes needed to mount protective immune responses. We demonstrate the use of a reconstituted manganous peptide complex from the radiation-resistant bacterium Deinococcus radiodurans to protect protein epitopes from radiation-induced damage and uncouple it from genome damage and organism killing. The Mn(2+) complex preserved antigenic structures in aqueous preparations of bacteriophage lambda, Venezuelan equine encephalitis virus, and Staphylococcus aureus during supralethal irradiation (25-40 kGy). An irradiated vaccine elicited both antibody and Th17 responses, and induced B and T cell-dependent protection against methicillin-resistant S. aureus (MRSA) in mice. Structural integrity of viruses and bacteria are shown to be preserved at radiation doses far above those which abolish infectivity. This approach could expedite vaccine production for emerging and established pathogens for which no protective vaccines exist.