ObjectiveTo humanize the variable region of the IL9-2G1 rabbit monoclonal antibody （IL9 2G1 mAb） and to evaluate its biological activity. MethodsThe humanized sequences of IL9-2G1 mAb were designed. The heavy chain variable region （VH） and light chain variable region （VL） of the antibody were humanized and cloned into vector backbones containing the constant region frameworks of human IgG1 and Ig Kappa subtypes. Protein purification was carried out using the Chinese hamster ovary cell （CHO） expression system. Enzyme-linked immunosorbent assay （ELISA） was used to qualitatively analyze the antigen-binding activity of the antibodies. After screening the optimal humanized antibody candidate， surface plasmon resonance （SPR） was performed to detect molecular affinity. Western blot was used to examine the effects of the rIL-9 group and the rIL-9 + hIL-9 mAb group on the phosphorylation of Janus kinase 1/signal transducer and activator of transcription 3 （JAK1/STAT3）， while ELISA was employed to assess the impact of the Th9 group and the Th9 + hIL-9 mAb group on interleukin-9 （IL-9） secretion. ResultsPurification and ELISA results showed that the heavy chain OH and light chain FL exhibited good compatibility and expression performance. SPR results indicated that the equilibrium dissociation constant （KD） of M501042-OHFL against the analyte M30903 was 1.33×10^-7 M， which was superior to the parental 2G1 antibody. The Western blot results showed that the levels of phosphorylated JAK1 （p-JAK1） and phosphorylated STAT3 （p-STAT3） were significantly decreased in the rIL-9 + hIL-9 mAb group compared with the rIL-9 group （P<0.01）. The ELISA results indicated that the secretion of IL-9 was significantly reduced in the Th9 + hIL-9 mAb group compared with the Th9 group （P<0.01）. ConclusionHumanization modification is performed on the variable region of IL9-2G1 rabbit monoclonal antibody， and the humanized antibody hIL-9 mAb OHFL with high affinity and strong binding stability is successfully constructed， which provides an experimental basis for subsequent research.

ObjectiveTo construct an interleukin-9 （Il9） gene knockout mouse model on a C57BL/6N background， establish a reliable genotyping method， and provide a standardized animal model for investigating Il9-related immune mechanisms and diseases. MethodsIl9 knockout mouse strain （C57BL/6N-Il9^em1Cya） was generated using conventional gene knockout technology. The method for DNA extraction from mouse tails was optimized to ensure template quality. Two sets of specific primers （F1/R1 and F1/R2） were designed to amplify target fragments by PCR， and mouse genotypes were determined by agarose gel electrophoresis. Specifically， primer pair F1/R1 targeted the knockout sequence with an expected product of 465 bp， while F1/R2 targeted the wild-type sequence with an expected product of 703 bp. Subsequently， Western blot was performed to verify the knockout efficiency of Il9 in primary immune cells and key organs of the offspring mice， and flow cytometry was used to assess the effects of Il9 deficiency on the function of the immune system in major immune cell populations. ResultsIl9 knockout mice were successfully bred and genotyped. PCR identification showed that homozygous mice （-/-） exhibited only a 465 bp band， wild-type mice （+/+） displayed only a 703 bp band， and heterozygous mice （+/-） showed both bands simultaneously. Meanwhile， Western blot analysis revealed significantly decreased IL-9 expression in various organs of the offspring mice （P<0.001）. Flow cytometric results demonstrated that Il9 deficiency exerted no obvious effects on the proportions of peripheral blood lymphocytes， splenic lymphocytes， and peritoneal macrophages. ConclusionAn Il9 gene knockout mouse model on a C57BL/6N background is successfully constructed. The established PCR genotyping system is highly efficient and accurate， which can effectively distinguish mice of different genotypes. This model provides a stable and reliable experimental basis for subsequent functional studies of Il9 and exploration of the mechanisms underlying Il9-related diseases.

ObjectiveTo construct a chimeric antigen receptor macrophage （CAR-M） targeting interleukin-13 receptor α （IL-13Rα） and intracellular domain integration， which can double activate the signal adaptor protein OX40L of macrophages and T cells. MethodsThe CAR molecule targeting IL-13Rα （IL-13Rα-OX40L-CAR） with OX40L as the intracellular signal domain was designed and synthesized， and it was cloned into the adenovirus expression vector. After THP-1 cells were induced to differentiate into macrophages （THP-1-M） by phorbol ester， the cells were infected with recombinant adenovirus to construct THP-1 macrophages stably expressing green fluorescent protein （GFP） labeled anti-IL-13RαCAR. The expression efficiency of CAR molecules was monitored by flow cytometry. The empty vector group was used as the negative control， the CD3ζ group was used as the positive control， and the CD3ζ-OX40L group was used as the experimental group. The phagocytic function of macrophages in each group on IL-13Rα high expression glioma cells （U251） and low expression glioma cells （T98G） was detected by in vitro co-culture experiments. ResultsCAR adenovirus was efficiently transfected into THP-1-M to obtain anti-IL-13RαCAR-M. After co-cultured with glioma cells with different expression levels of IL-13Rα， the results of flow cytometry showed that there was no significant difference among the three groups for T98G cells with low expression of IL-13Rα. After co-culture with U251 cells with high expression of IL-13Rα， the CD3ζ group showed enhanced phagocytosis compared with the empty vector group （P<0.05）. Compared with the CD3ζ group， the phagocytosis ability of the CD3ζ-OX40L group was further enhanced （P<0.05）. ConclusionAnti-IL13Rα- OX40L-CAR-M is successfully constructed by constructing IL-13Rα-OX40L-CAR adenovirus and transfecting PMA-induced differentiated THP-1-M. It can engulf glioma cells with high expression of IL-13Rα by specific targeting， and shows activation of intracellular domain superior to traditional CD3ζ.

ObjectiveTo construct B cell conditional knockout Spi1 gene mice and analysis their genotypes to provide an animal model basis for disease pathogenesis and drug target research. MethodsMb1-cre transgenic mice were crossed with Spi1^flox/flox mice. PCR combined with agarose gel electrophoresis was performed for genotyping， and Mb1-cre×Spi1^flox/flox homozygous knockout mice were screened out. Flow cytometry was used to detect the expression of PU.1 protein in various immune cell subsets to verify the specificity of gene knockout. ResultsPCR identification results showed that when using flox primers for detection， only a 220 bp band was amplified， indicating a genotype of Spi1^flox/flox in the mice. When using Mb1-Cre primers for detection， a 383 bp band was amplified， indicating a genotype of Mb1-cre×Spi1^flox/flox in the mice； Flow cytometry results showed that compared to Spi1^flox/flox mice， Mb1-cre×Spi1^flox/flox mice exhibited significantly reduced PU.1 expression levels in bone marrow-derived mononuclear cells， peripheral blood mononuclear cells， and spleen-derived B cells. Moreover， PU.1 exhibited normal expression in other immune cells， such as CD4⁺ T cells and macrophages. ConclusionBy utilizing the Cre/LoxP system and CRISPR/Cas9 technology， this study successfully generates mice with B cell-specific conditional knockout of the Spi1 gene， providing a reliable animal model for in-depth exploration of the specific role of PU.1 in B cell-related diseases.

ObjectiveTo obtain a construct chimeric antigen receptor macrophages （CAR-M） targeting disialoganglioside GD2 （GD2） and harboring the intracellular domain of macrophage-specific activating signaling adaptor protein DNAX-activating protein 12 （DAP12）. MethodsA CAR molecule targeting GD2 with the DAP12 intracellular domain as the signaling module ［Anti-GD2 CAR （DAP12）］ was designed， synthesized， and cloned into an adenoviral vector. This virus was used to infect PMA-differentiated THP-1 macrophages to construct green fluorescent protein （GFP）-labeled Anti-GD2 CAR THP-1 cells. CAR expression was confirmed using live-cell imaging. In vitro co-culture assays were performed to evaluate the phagocytic function of empty， Anti-GD2 CAR-M （CD3ζ）， and Anti-GD2 CAR-M （DAP12） groups against glioma cells with high （T98G） and low （U251） GD2 expression. ResultsThe CAR adenovirus efficiently transduced THP-1 macrophages， resulting in successful generation of Anti-GD2 CAR-M. Flow cytometry analysis following co-culture with glioma cells showed that compared to the empty group， the Anti-GD2 CAR-M （CD3ζ） group exhibited significantly enhanced phagocytosis （P<0.05）. Furthermore， compared to the Anti-GD2 CAR-M （CD3ζ） group， the Anti-GD2 CAR-M （DAP12） group demonstrated a further increase in phagocytic capacity specifically against GD2-high T98G cells （P<0.05）. ConclusionAnti-GD2 CAR-M （DAP12） cells are successfully established by transducing PMA-differentiated THP-1-M with recombinant Anti-GD2 CAR （DAP12） adenovirus. The engineered CAR-M can specifically target phagocytose glioma cells with high GD2 expression.

ObjectiveTo obtain stably transfected chimeric antigen receptor macrophages （CAR-M） targeting disialosylganglioside （GD2） based on the constitutive expression of myeloid differentiation factor 88 （MYD88）. MethodsAn Anti-GD2 CAR adenoviral vector incorporating the CD3ζ （cluster of differentiation 3 zeta chain）-MYD88 fusion construct was designed and constructed. THP-1-derived macrophages （THP-1M）， induced by phorbol 12-myristate 13-acetate （PMA） differentiation， were infected with this adenovirus to generate Anti-GD2 CAR THP-1 cells bearing a green fluorescent protein （GFP） tag. CAR expression was monitored using a live-cell imaging system. The phagocytic function of Empty CAR-M， Anti-GD2 CAR-M（CD3ζ）， and Anti-GD2 CAR-M（CD3ζ-MYD88） groups against glioma cells was evaluated in vitro through co-culture experiments， and their polarization status was also analyzed. ResultsCAR adenovirus successfully transfected THP-1 to obtain Anti-GD2 CAR-M. After co-culture with glioma cells， flow cytometry results showed that compared with the Empty CAR-M group and the Anti-GD2 CAR-M（CD3ζ） group， the Anti-GD2 CAR-M（CD3ζ-MYD88） group exhibited enhanced phagocytosis against T98G cells with high GD2 expression （P<0.05） and also showed upregulation of CD86 （P<0.05）. Compared with the Empty CAR-M group and the Anti-GD2 CAR-M（CD3ζ） group， the Anti-GD2 CAR-M（CD3ζ-MYD88）CAR-M group exhibited enhanced phagocytosis against T98G cells with high GD2 expression （P<0.05） and also showed upregulation of CD86 （P<0.05）， and the expression of inflammatory cytokines interleukin （IL）-6 and IL-12 was increased in this group （P<0.05）. ConclusionThis study successfully constructed Anti-GD2 CAR-M cells and verified their phagocytic activity， demonstrating that constitutive expression of MYD88 can promote inflammatory polarization of CAR-M. This provides a potential structural modification approach for the development of pro-inflammatory CAR-M.

Objective: To constructCSF1R+/-mice and to analyze their genotypes, so as to provide animal model basis for disease pathological mechanism and drug target. Methods : A linearized targeting vector was designed according to Cre/Loxp system. A Loxp site was inserted upstream of the 5th exon of theCSF1Rgene, and a neomycin resistance box with Loxp sites on both sides was inserted downstream of the 5th exon. The linearized targeting vector was electroporated into embryonic stem cells. The correctly targeted embryonic stem cells were injected into the blastocysts of C57BL/6J mice to obtain chimeric mice, which were bred with Zp3-Cre mice. The newborn mice were numbered 9-14 days after birth and their tails were cut. The DNA of the mice was extracted, and the genotype of the mice was identified by polymerase chain reaction and agarose gel electrophoresis. The expression of CSF1R in mouse macrophages was detected by flow cytometry. The expression of CSF1R in mouse tissues was detected by Western blot. Results: The results of agarose gel electrophoresis showed that 453 bp bands were amplified in wild type mice, and 453 bp and 650 bp bands were amplified in heterozygous mice. The results of flow cytometry showed that the expression of CSF1R in peritoneal macrophages and bone marrow-derived macrophages of CSF1R heterozygous mice was lower than that of WT group(P<0.05). The results of Western blot showed that the expression of CSF1R in spleen, kidney and brain tissue of CSF1R heterozygous group was lower than that of WT group(P<0.05). Conclusion CSF1R+/-mice are successfully constructed, reproduced and identified, which provides an animal model basis for further revealing the potential mechanism of CSF1R in immune regulation.

Objective : To construct triggering receptor expressed on myeloid cells 2(TREM2) gene knockout(TREM2-/-) mice using CRISPR/Cas9 technology, to breed TREM2-/- mice and to analyze the genotype of TREM2-/- mice. Methods : CRISPR/Cas9 technology was used to selectively knock out exon 2-3 regions of TREM2 gene to construct a TREM2-/- mouse model, and the genetic background of all mice was C57BL/6J. Polymerase chain reaction(PCR) was used to identify the genotype of mice. Quantitative real-time PCR(qPCR) and Western blot were used to detect the expression level of TREM2 in major tissues of mice, and the authenticity and scientific nature of PCR identification results were verified from mRNA level and protein level. According to the sgRNA sequence, the possible off-target sites were predicted on the CCTop website, and the tail DNA of mice was extracted and amplified by PCR and then Sanger sequencing was performed to detect whether there was off-target effect in TREM2-/- mice. Results : TREM2-/- mice were successfully constructed by CRISPR/Cas9 technology, and the mice were genotyped. The results of agarose gel electrophoresis showed that the mouse genotype with only 415 bp band amplified was wild type(WT), the mouse genotype of the 449 bp band amplified only was TREM2-/-, and the mouse genotypes amplified with 415 bp and 449 bp double bands were heterozygous. qPCR results showed that compared with WT mice, the mRNA expression of TREM2 in heart and brain tissues of TREM2-/- mice was down-regulated(P-/- mice was reduced(P-/- mice. Conclusion TREM2-/- mice are successfully constructed and bred, a reliable genotype identification method is established, the genetic stability of the mouse model is verified, which will provide an important genetic animal model for the study of TREM2 gene function.

Objective : To construct a humanized mouse model of the interleukin-9 receptor(IL-9R) coding DNA sequence(CDS) gene and to verify the genotype and IL-9R expression in mice. Methods : The CRISPR/Cas9 genome editing technology was used to replace the exon 2-7 fragment of the il-9r gene in mouse embryonic stem cells with the corresponding human IL-9R sequence. After verifying the completion of the gene fragment replacement, tetraploid embryos were constructed and microinjected back into the oviducts of surrogate mice. Through surrogacy by female mice, homozygous humanized mice were obtained. DNA was extracted from the homozygous humanized mice IL-9R CDS gene, and their genotypes were identified by agarose gel electrophoresis after PCR amplification. Western blot was used to detect the expression of IL-9R in the spleen and thymus of homozygous humanized mice with either wild-type(WT) or IL-9R gene humanization. Results : Gel electrophoresis after PCR amplification showed that mice with only a 1 805 bp band amplified using WT primers were wild-type, while mice with 2 553 bp and 2 340 bp bands amplified using 5KI and 3KI primers, respectively, were homozygous humanized mice with IL-9R CDS gene. Western blot results indicated that the tissues of homozygous humanized mice model with IL-9R CDS gene expressed IL-9R significantly. Conclusion The humanized mouse model with IL-9R CDS gene has been successfully constructed and characterized.

Objective: To construct microRNA(miR)-22 gene knockout(miR-22-/-) mice using CRISPR/Cas 9 technology, to breed miR-22-/- mice and to identify their genotypes. Methods : In this experiment, CRISPR/Cas 9 technology was used to construct miR-22-/- genetically engineered mice. After gene identification, the F0 generation miR-22-/- mice were mated with wild-type mice in the same litter to obtain F1 generation miR-22-/- mice. The miR-22 knockout efficiency was analyzed at the RNA level by real-time fluorescence quantitative polymerase chain reaction(qPCR). Western blot was used to detect the interaction between miR-22 and target genes. Results : miR-22-/- mice were successfully constructed using CRISPR/Cas 9 technology, gene identification was performed on the bred mice, and three stable genotypes of miR-22+/+,miR-22+/-, and miR-22-/- were identified. The real-time fluorescence quantitative PCR detection results confirmed that miR-22-/- mice showed almost no expression of miR-22 in the heart, liver, lung, kidney, spleen, and thymus tissues compared to wild-type mice in the same litter. Western blot analysis showed that the relative expression level of NLRP3 protein in miR-22-/- mouse tissues was lower than that in wild-type mice. Conclusion A miR-22-/- mouse model is successfully constructed, and stable genetic homozygous miR-22-/- mice is obtained. This indicates that miR-22 has an inhibitory effect on the downstream target gene NLRP3.