[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.

[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.

ObjectiveXenotransplantation is an effective way to address the shortage of human organ donors, but it faces serious immune rejection reactions, including hyperacute rejection caused by blood type differences. Establishing a stable, convenient, and reliable method for pig blood type identification can quickly screen suitable donor pigs for xenograft research.MethodsBanna miniature inbred pigs, Diannan small eared pigs, and Bama Xiang pigs were selected as the research objects. DNA was extracted from the blood, oral buccal mucosa, and fetal fibroblasts of the three strains of pigs using DNA extraction kits. The target fragment of the ABO homologous gene EAA intron 7 in pigs was amplified using PCR method. Blood agglutination reaction was used to detect hemolysis in pig anterior vena cava whole blood after adding anti A and B antibodies. Immunohistochemical method was used to detect the expression level of A antigen in pig heart, liver, spleen, lung, and kidney tissues. Immunofluorescence method was used to detect the expression level of A antigen in pig oral mucosa. By comparing the results of different methods for determining pig blood types, the stability and reliability of the PCR method were verified, and a convenient PCR based pigblood type identification method was established.Results Firstly, the blood PCR results of 69 inbred strains of Banna miniature pigs, 7 Diannan small eared pigs, and 34 Bama Xiang pigs showed 20 AO blood types, 66 AA blood types, and 24 O blood types. The PCR results of fetal fibroblasts from 47 Diannan small eared pigs showed that all 47 fetuses were O blood type. Among them, the oral mucosal PCR results of 8 gene edited cloned pigs were consistent with those of donor fetal fibroblasts, all of which were O blood type. The oral mucosal PCR results of 8 wild-type pigs (2 inbred lines of Banna miniature pigs, 4 Diannan small eared pigs, and 2 Bama Xiang pigs) were consistent with the blood PCR identification results. Then, 11 inbred lines of Banna miniature pigs, 4 Diannan small eared pigs, and 2 Bama Xiang pigs were randomly selected for blood agglutination reaction validation, and the results were consistent with the PCR identification results of both blood samples and oral mucosa samples. Moreover, immuno-histochemical analysis was performed on the heart, liver, lung, kidney, and spleen tissues of one Banna miniature pig inbred line and two Bama Xiang pigs, and the results were consistent with blood PCR identification and blood agglutination reaction results. Finally, oral mucosal samples were collected from 2 inbred strains of Banna miniature pigs and 1 Bama Xiang pig for immunofluorescence detection, and the results were consistent with the blood PCR identification results.ConclusionBy collecting fetal cells and oral mucosal samples from live pigs for PCR detection, the blood type of pigs can be accurately and efficiently identified, providing a convenient method for blood type screening of xenograft donor pigs.

Objective To construct a Type 1 diabetes model in miniature pigs and explore postoperative care strategies for effectively prolonging the survival time of the model pigs. Methods Seven Banna miniature pigs were selected for pancreatectomy. Glucose, vitamins, and antibiotics were administered for 3-5 days after surgery to aid recovery. Blood glucose and urine glucose levels were measured twice a day in the morning and evening to adjust insulin supplementation accordingly. The model pigs were observed daily and records were kept, including orexis, psychosis, weakness, skin ulcer, and feces and urine. Body weight was measured weekly until the death of the model animals. Based on the model pigs' condition, glucose injection and Ringer's lactate solution were administered to supplement nutrition and correct electrolyte imbalances. Results All seven Banna miniature pigs showed typical symptoms of diabetes: random blood glucose levels higher than 11.1 mmol/L after pancreatectomy, far exceeding the average blood glucose level of 6.0 mmol/L in normal pigs; positive urine glucose; and progressive weight loss. These features indicated the successful construction of Type 1 diabetes model. Additionally, Type 1 diabetic pigs that survived more than 8 weeks showed progressive hair loss and skin ulceration. Euthanasia was performed on model pigs when they were unable to stand or even eat independently, and pathological examination and HE staining were conducted on tissues collected from affected organs such as the liver, kidneys, and skin. Pathological sections revealed liver congestion, massive glycogen accumulation, ballooning degeneration of hepatocytes, and progressive liver fibrosis, along with glomerular congestion, vacuolar degeneration in renal tubular epithelial cells, proteinuria, dermal congestion, thinning of vascular walls, and varying degrees of parakeratosis and dyskeratosis in the liver, kidneys, and skin tissues due to prolonged hyperglycemia. The average survival time of the constructed Banna miniature pig diabetes model was 44 d, with a maximum survival time of 121 d. Conclusion Type 1 diabetes model can be constructed successfully in Banna miniature pigs through pancreatectomy. With meticulous postoperative care, a long-term Type 1 diabetes model with significant complications can be achieved, providing a stable large-animal model for Type 1 diabetes treatment strategies.