[Construction and Optimization of CD19 Chimeric Antigen Receptor T Cells Derived from C57BL/6J Mice]

To explore the stimulation conditions, optimal culture time and infection time of C57BL/6J mice CD3⁺ T cells in vitro, so as to improve the infection efficiency of CD19 chimeric antigen receptor T cells (mCD19 CAR-T).

Purified C57BL/6J mice CD3⁺ T cells were cultured in anti-CD3/CD28 coated, anti-CD3 coated+soluble anti-CD28 and anti-CD3 coated, respectively. The cells were stimulated in above three conditions for 12 h and 24 h, following with 24 h, 48 h and 72 h incubation and then the number of cell clones was recorded. C57BL/6J mice CD3⁺ T cells were stimulated for 12 h, 24 h, and 36 h under the above three conditions, then interleukin (IL)-2 (100 U/ml) was added. The number of cell clones was recorded under microscope at 24 h, 48 h, and 72 h of culture. After 24 h of stimulation, CD3⁺ T cells derived from C57BL/6J mice were infected with retrovirus for 48 h to establish mCD19 CAR-T cells, and the percentage of GFP⁺ CAR-T cells was detected by flow cytometry.

The infection efficiency of mCD19 CAR-T cells derived from C57BL/6J mice was only 5.23% under the optimized conditions of mCD19 CAR-T cells derived from BALB/c mice. The number of clones of C57BL/6J mice CD3⁺ T cells was the highest in anti-CD3 coated+soluble anti-CD28 group after stimulated for 24 h and followed cultured for 48 h. After 24 hours of stimulation under the above conditions and 48 hours of culture with IL-2, the number of T cell proliferating clones in the anti-CD3 coated+soluble anti-CD28 group was significantly increased compared with the same group without IL-2, and the infection efficiency of CAR-T cells in this group reached 17.63%±4.17%.

The optimal conditions for constructing CAR-T cells from C57BL/6J mice CD3⁺ T cells are different from those of BABL/c mice. T cells stimulated by anti-CD3 coated+soluble anti-CD28+IL-2 can obtain mCD19 CAR-T cells with the highest efficiency after retrovirus infection.