Amy S. Yu (United States of America)
Stanford University School of Medicine Radiation OncologyAuthor Of 1 Presentation
RAPID CONVALESCENT PLASMA STERILIZATION USING HIGH DOSE RATE ELECTRON RADIATION
Abstract
Background and Aims
Passive antibody administration through convalescent plasma has shown benefit in treating COVID-19 in the early stages of the disease in patients >65 years old, and in other viral outbreaks. A practical, rapid method to sterilize convalescent plasma while also maintaining antibody function would be valuable for safe treatment in future viral pandemics. Plasma sterilization by irradiation requires kGy of dose to deactivate bacteria and viruses of concern. Conventional lab-based irradiators would require days to reach such doses, while ultra-high dose rate irradiation (FLASH) would require minutes. We present a proof-of-concept on sterilizing plasma with 25 kGy in approximately 3 minutes without damaging the antibodies in the plasma.
Methods
A Varian Trilogy LINAC was configured for 16 MeV FLASH electron irradiation. Frozen aliquots of convalescent plasma from patients with COVID-19 were placed in a 3D printed holder submerged in liquid aiming to preserve sample temperature (RT, 4C or -20C). The number of pulses was estimated with EBT-XD film. Samples were irradiated with a dose of 25 kGy in ~33,330 pulses over 185 seconds. Antibody binding against the receptor-binding domain (RBD) of the S1 region of SARS-CoV-2 was measured by ELISA pre- and post-irradiation.
Results
Frozen plasma aliquots from 10 COVID-19 convalescent plasma donors were irradiated in frozen state to 25 kGy dose. IgG antibody binding against SARS-CoV-2 RBD after irradiation remained at 90.8% of non-irradiated samples (Figure; OD 1.25 vs. 1.36, p< 0.0003).
Conclusions
FLASH irradiation allows for rapid sterilization of blood plasma from potential pathogens while largely preserving antibody binding function and specificity.