COVID 19 PlasmaIn a newly published study, researchers at Colorado State University and biotech company Terumo cited using COVID-19 convalescent plasma sourced from Cellero for their study on pathogen reduction technology. [1]

Convalescent blood plasma is often used as a stop-gap treatment for viral diseases while other treatments are being developed. The plasma can help patients fight off disease, since it contains antibodies generated against the virus by the donor patient.

While using convalescent plasma treatment can be lifesaving, it also carries a risk. Plasma, like any blood product, can carry blood-borne pathogens with which the donor is infected. To minimize the risk of disease transmission through donated blood products, plasma is treated using pathogen reduction technologies (PRT) aimed at reducing viral loads and preventing the ability of any virus to reproduce and infect cells. PRT is widely used in hospitals and clinics where blood transfusions are done and has been proven to be highly effective.

The use of PRT to treat COVID-19 convalescent donor plasma, however, presented a conundrum to COVID-19 researchers. It is uncertain whether the same treatment used to incapacitate viral pathogens might also degrade the SARS-CoV-2 antibodies present in the plasma, thereby destroying its therapeutic and scientific value. The Colorado-based researchers consequently set out to evaluate the effects of a commonly used PRT technique, co-treatment with riboflavin and UV-light, on the functional properties of COVID-19 convalescent plasma.  

The study used COVID-19 convalescent plasma units from 6 different donors and  were acquired from Key Biologic/Cellero and stored at -20°C prior to further analysis. Cellero plasma units are collected via apheresis.  Donors are certified as having tested positive for the presence of SARS-CoV-2 virus and diagnosed with COVID-19, then subsequently having recovered and tested negative for the virus. Cellero convalescent plasma inventory includes individuals who experienced minimal symptoms, along with others who had significant illness. The history of the donor’s illness is included on the certificate of analysis along with HLA typing and antibody titers.

For this study, convalescent plasma units were treated using a riboflavin + UV-light PRT system. After treatment, the plasma units were analyzed for selected coagulation factors and immunoglobulins, and for antibody binding to the SARS-CoV-2 spike protein. The group also tested for antibody neutralizing activity by using a synthetic viral reporter particle acting as a stand in for SARS-CoV-2.

Study results showed a successful outcome for COVID-19 convalescent plasma quality retention after riboflavin + UV-light PRT treatment. Coagulation factors were reduced upon treatment, but still retained at 70% or greater. Immunoglobulin factors were not affected by treatment and were retained at 100%. All 6 donor units demonstrated antibody binding to SARS-CoV-2 spike protein as assessed by ELISA. SARS-CoV-2 neutralizing activity was well preserved and detected in all convalescent plasma samples after PRT treatment.

Convalescent plasma donated by recovering COVID-19 patients has been an extremely valuable resource from early in the pandemic not only for its value in treating patients, but as a means of isolating and studying antibody production against the virus. [2] It is still the most readily available source of anti-SARS-CoV-2 antibodies, particularly in locations with limited resources where vaccine deployment is lacking.

In addition to convalescent plasma, Cellero carries a variety of immune cell products necessary to COVID-19 research, including COVID-19 patient PBMC, COVID-19 serum, T cell line specific for a peptide from the spike protein of SARS-CoV2 and PBMC, serum, and plasma from vaccinated donors. For a complete list of COVID-19 related immune cell products, please visit our website to discover which products are the best fit for your research.



  1. Yonemura S., et al. Preservation of neutralizing antibody function in COVID-19 convalescent plasma treated using a riboflavin and ultraviolet light-based pathogen reduction technology. Vox Sanguinis. April 2021.
  2. Libster R., et al. Early High-Titer Plasma Therapy to Prevent Severe Covid-19 in Older Adults. NEJM. Jan 2021.

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