Immunotherapy: TIMING OF DONOR SELECTION ON CD45RA-MEMORY T CELLS AS ADOPTIVE CELL THERAPY FOR COVID-19

ABSTRACT

Background & Aim: The COVID-19 pandemic has resulted in significant morbidity and mortality worldwide. The vaccines had dramatically decreased infection rates, number of deaths, and hospitalizations, but they are not 100% effective and immunity is lost gradually over time. We have previously shown how we are able to detect, isolate and produce at clinical scale SARS-CoV-2-specific T cells within CD45RA-memory T cells from COVID-19 convalescent donors. In a phase I clinical trial we have proved that treatment with these cells of hospitalized patients with moderate/severe COVID-19 is safe and feasible. Understanding the durability and the level of cellular immunity within the CD45RA- memory T cells and how changes with immunization are critical for the development of a biobank of living drugs to treat future COVID-19 patients. We performed a longitudinal exploratory analysis of the SARS-CoV-2 specific humoral and cellular immunity within the memory CD45RA- T cells in naive and previously infected individuals at different time points after two doses of BNT162b2 BioNTech/Pfizer vaccine Methods, Results & Conclusion: We studied the cellular and humoral response of SARS-CoV-2 specific memory T cells from recovered patients and controls at different time points 2 weeks after recovering from COVID-19, 9 months after the infection/just before mRNA immunization, 10 and 65 days after full immunization. Detection of SARSCoV- 2- Specific Memory T Cells was performed by IFNg assay after exposure of cells to the M, N, and S SARS-CoV-2 peptides. Our data shows that memory T cell responses within the CD45RA- memory T cell subpopulation and most of the subsets tend to be higher in recovered individuals at all time points. The cellular response produced by control individuals to the S peptide is like the one from recovered patients at the same time point. Humoral responses were higher in recovered individuals after full immunization. Antibodies titer was not boosted after the late vaccine time point. An exploratory analysis of non-parametric Spearman’s rho correlation of humoral and cellular responses shows a positive correlation after infection with the 3 peptides and 65 days after immunization. In conclusion: We have analyzed the SARS-COV-2 specific T cells within the CD45RA- memory T cell subpopulation and the different subsets at different time points after (Figure Presented) (Figure Presented) infection and fully vaccinated. We claim that the best donors would be immunized individuals recovered from COVID-19 ideally in a time frame not higher than 6 months.