Group O plasma as a media supplement for CAR-T cells and other adoptive T-cell therapies

BACKGROUND: Most chimeric antigen receptor T (CAR-T) cells and other adoptive T-cell therapies (ACTs) are currently manufactured by ex vivo expansion of patient lymphocytes in culture media supplemented with human plasma from group AB donors. As lymphocytes do not express A or B antigens, the isoagglutinins of non-AB plasmas are unlikely to cause deleterious effects on lymphocytes in culture. STUDY DESIGN AND METHODS: Seeding cultures with peripheral blood mononuclear cell (PBMNC) concentrates from group A₁ donors and using a CAR-T culture protocol, parallel cultures were performed, each with unique donor plasmas as media supplements (including group O plasmas with high-titer anti-A and group AB plasmas as control). An additional variable, a 3% group A₁ red blood cell (RBC) spike, was added to simulate a RBC-contaminated PBMNC collection. Cultures were monitored by cell count, viability, flow cytometric phenotype, gene expression analysis, and supernatant chemokine analysis. RESULTS: There was no difference in lymphocyte expansion or phenotype when cultured with AB plasma or O plasma with high-titer anti-A. Compared to controls, the presence of contaminating RBCs in lymphocyte culture led to poor lymphocyte expansion and a less desirable phenotype—irrespective of the isoagglutinin titer of the plasma supplement used. CONCLUSIONS: This study suggests that ABO incompatible plasma may be used as a media supplement when culturing cell types that do not express ABO antigens—such as lymphocytes for CAR-T or other ACT. The presence of contaminating RBCs in culture was disadvantageous independent of isoagglutinin titer.