Discipline: Biological Sciences
Subcategory: Cancer Research
Jasmine Perry - North Carolina Central University
Co-Author(s): Brandon Kale, Lineberger and Barbara Savoldo, Department of Pediatrics, Lineberger Comprehensive Cancer Center, University of North Carolina, Chapel Hill, NC
Chimeric antigen receptor (CAR) T cell therapy is an immunotherapy approach that exploits the immune system to attack and eliminate tumors for patients with hematologic malignancies. CAR T cells combine the targeting capacity of the antibodies of B cells with the attack advantages of T cells. To express the desired CAR, T-lymphocytes are activated using CD3-CD28 specific monoclonal antibodies (MAbs) available in different formats: soluble, plate-bounded (immobilized, I), coated beads (Dynabeads, D), or conjugated on a polymeric nanomatrix (Transact, T). Although adoptive transfer of T-cells with a CD19-specific-CAR (CAR-Ts) have shown remarkable clinical efficacy in patients with B-cell-malignancies, the optimal method of activation of T lymphocytes for expansion, persistence, and antitumor effectiveness of CAR-Ts is unknown. We have therefore undertaken a comparison of these approaches in three heathy buffy-coats donors, hypothesizing that CD3/CD28-coated-beads will prove superior as they have more available binding-sites and are continuously present during CAR-Ts expansion as beads are removed at the time of the product infusion. We used flow cytometry to assess CAR expression. We found comparable expression between methods: I-CD19.CAR-Ts, 84.5%±2.6%; D-CD19.CAR-Ts, 86.2%±5.0%; and T-CD19.CAR-Ts 84.7%±3.2%. All CAR-Ts expanded well, although a trend for higher fold-increase was observed for CAR-Ts generated with I-CD3/CD28. Interestingly, higher mean fluorescence intensity (MFI) was observed in D-CAR-Ts and T-CAR-Ts (10468±5561, 7669±2182 vs 3997±1046 in I-CAR-Ts). Immune profile of CAR-Ts showed similar composition between activation methods in term of CD4+/CD8+, memory and effector cells. Killing activity based on co-culture assays confirmed that all CAR-Ts eliminated CD19+ tumors regardless of activation method. We observed no differences in cytokine production or proliferative potential. Our preliminary data suggests that all strategies generate efficient CD19.CAR-Ts; therefore, each method proved to be effective, and the initial hypothesis was disproven. We will next explore potential differences in their vivo efficacy in a CD19+ leukemia xenograft model.
Funder Acknowledgement(s): Jasmine Perry was funded by NCCU-LCCC Partnership grant U54 CA156735 from NCI/NIH.
Faculty Advisor: Tonya Gerald-Goins, firstname.lastname@example.org
Role: During the research process, I cultured the T lymphocytes and introduced each test group to the corresponding activation method. After each group was activated, I continued to culture the cells, and I conducted assays to determine the characteristics of the cells.