RESUMO
@#[Abstract] Objective: To investigate the effects of CRISPR/Cas9 gene editing mediated PD-1 knockdown on the proliferation, phenotype, IFN-γ and IL-2 secretion of T cells in Cynomolgus monkeys. Methods: gRNA targeting PD-1 gene of Cynomolgus monkey was designed, and the corresponding plasmid was constructed and extracted. peripheral blood mononuclear cells (PBMCs) of Cynomolgus monkeys were isolated, and plasmid DNAs were added for transfection by using Lonza 4D electrorotometer. FACS analysis and fluorescence microscopy were used to detect transfection efficiency at 48 h after transfection. Genomic DNA of T cells was extracted for PCR amplification and T7E1 digestion identification. The proliferation of T cells was induced under the stimulation of human CD3 antibody and IL-2, and the cell growth curve was drawn. PI staining flow cytometry was used to detect cell cycle and the expression levels of CD4 and CD8, and ELISA was used to detect the secretion of IFN- γ and IL-2. Results: At 48 h after transfection, the cells with green fluorescent protein expression in experimental group were observed under fluorescence microscopy with a transfection efficiency of (21.6±3.2)%. T7E1 enzyme digestion results showed that the PCR product of genomic DNA of cells in experimental group showed 3 bands after digestion, including the target cleavage bands(243，197 bp). Compared with non-transfected cells, the cells in experimental group exhibited slow proliferation, delayed colony formation, with small volume and weak refraction; the number of T cells at G0/G1 phase of the experimental group was significantly increased (P<0.05), while the number of cells at G2/M phase was significantly reduced (P<0.05); and the secretion levels of IFN-γ and IL-2 in the cells of the experimental group increased significantly (both P<0.05). However, the difference in the expression levels of CD4 and CD8 was not statistically significant between the two groups (both P>0.05). Conclusion: PD-1 gene knockout can arrest T cells in Cynomolgus monkey at G0/G1 phase, thereby inhibiting its proliferation and increasing the secretion of IFN-γ and IL-2 in the meanwhile.
RESUMO
@#[Abstract] Objective: To establish a method for in vitro isolation and culture of T lymphocytes from peripheral blood of cynomolgus monkeys that induced by human CD3 antibody based on the foundation of protein homology of CD3 from human, cynomolgus monkey and porcine. Methods: The amino acid sequences of human, cynomolgus monkeys and porcine CD3 proteins were obtained from NCBI, and the sequence, homology and phylogenetic tree were analyzed by DNAMAN software. Western blotting was used to detect the expression of CD3 protein on T cell membranes from the three species. PBMCs of healthy cynomolgus were isolated and divided into three groups: group A was stimulated with anti-human CD3Ab alone, group B was stimulated with IL-2 alone, and group C was costimulated with human CD3Ab and IL-2. Cell morphology and growth status were observed under inverted microscope and the cell growth curve was plotted. Cell viability was detected by trypan blue staining and the expressions of CD3, CD4 and CD8 on T cell surface were detected by flow cytometry. Results: The homology of the amino acid sequence of human CD3 protein to cynomolgus monkey and porcine were 86.9% and 65.6% respectively. The expression levels of CD3 protein on cynomolgus and porcine T cell membrane were 79% and 17% contrast to human, respectively. Cells of group A did not proliferate. Proliferation, viability and CD3 expression [(93.8±3.6)% vs (70.3±4.7)%, P<0.01] in T cells of group C were significantly higher than those in group B. Growth curve of T cells in group C showed an S-shape, which is consistent with Logistic growth curve. T cells in group C exhibited high purity and expressed high level CD3; moreover, the CD8+T cell took a high proportion. Conclusion: The membrane of T lymphocytes from peripheral blood of cynomolgus can express CD3 protein that highly homological to human. Co-stimulation of human CD3Ab, IL-2 and 1% PHAcan induce the proliferation and differentiation of T lymphocytes of cynomolgus, and obtain T lymphocytes with good growth status, high proliferation ability and high purity.