Basic Information
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Targeting strategy
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Gene targeting strategy for B-hSIGLEC8 mice. The BAC containing the whole sequence of human SIGLEC8 gene was inserted into Rosa26 locus in B-hSIGLEC8 mice.
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Protein expression analysis
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SIGLEC8 protein expression analysis in humanized B-hSIGLEC8 mice by flow cytometry. Blood and peritoneal lavage fluid were collected from wild-type C57BL/6 (+/+) and homozygous B-hSIGLEC8 (H/H) mice, and analyzed by flow cytometry using an anti-hSIGLEC8 antibody. Human SIGLEC8 protein was detected in eosinophils (88%, mSiglec-F+,mCD11c-) and mast cells (99.8%, mFcεRIα+,mCD117(c-kit)+,CD11b-) in B-hSIGLEC8 mice.
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Eosinophils and mast cells in B-hSIGLEC8 mice bind to anti-human SIGLEC8 antibody
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SIGLEC8 protein expression analysis in eosinophils and mast cells from humanized B-hSIGLEC8 mice. Eosinophils and peritoneal lavage-mast cells isolated from wild-type C57BL/6 (+/+) and B-hSIGLEC8 (H/H) mice were analyzed by flow cytometry to assess human SIGLEC8 protein expression using the Benchmark antibody Lirentelimab (in house). Eosinophils were gated from mSiglec-F+,mCD11c- population, while mast cells were gated from CD45+mFcεRIα+,mCD117(c-kit)+CD11b- population. Lirentelimab exclusively bound to human SIGLEC8 in B-hSIGLEC8 mice compared to wild-type mice.
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The number of BALF immune cells in mouse asthma model
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The number of BALF Immune cells in mouse asthma model. BALF Immune cells were isolated from B-hSIGLEC8 mice (n=6). The number of eosinophils was analyzed by flow cytometry under the treatment of PBS or lirentelimab (in house). After treatment of lirentelimab, the expression level of inflammatory cells was lower than the positive control in homozygous B-hSIGLEC8 mice.
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In vivo efficacy of anti-human SIGLEC8 antibody
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H&E staining in asthma-like model in B-hSIGLEC8 mice. (A) Lung tissues were collected from at the study end point. H&E staining results showed that the lung tissues from B-hSIGLEC8 mice exposed to PBS aerosols did not show any inflammation. OVA exposure resulted in a significant increase in peribronchial and perivascular inflammation in B-hSIGLEC8 mice. (B) A significantly reduction in eosinophils infiltration was observed in mice treated with lirentelimab (in house).
Note: The lirentelimab in the treatment model group were administered via intratracheal aerosolization.
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Summary
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Protein expression analysis:
Human SIGLEC8 was detectable in Eosinophils(88%) and mast cells (99.8%) in homozygous B-hSIGLEC8 mice.
In vivo efficacy：
Anti-human SIGLEC8 antibody was efficacious in reducing eosinophils induced by OVA in B-hSIGLEC8 mice .
