Basic Information
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Gene Targeting Strategy
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Gene targeting strategy for B-hTSLP/hTSLPR mice. The exons 1-5 of mouse Tslp gene that encode the full-length protein were replaced by human TSLP exons 1-4 in B-hTSLP/hTSLPR mice. The extracellular and transmembrane region of human TSLPR gene and the cytoplasmic region of mouse Tslpr gene were constructed into a chimeric CDS vector and inserted into the mouse exon 2. The targeted mice will express the chimeric TSLPR protein, while mouse TSLPR will no longer express.
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mRNA expression analysis
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Strain specific analysis of TSLP and TSLPR gene expression in wild type C57BL/6 mice and homozygous B-hTSLP/hTSLPR mice by RT-PCR. Mouse mRNA was prepared from ear grinding supernatant of wild type C57BL/6 mice (+/+;+/+) and homozygous B-hTSLP/hTSLPR mice (H/H;H/H) stimulated with calcipotriol (MC903). Mouse Tslp mRNA was only detectable in wild type C57BL/6 mice (+/+;+/+). Human TSLP mRNA was only detectable in homozygous B-hTSLP/hTSLPR mice but not in wild type mice. Mouse mRNA was prepared from splenocytes of wild type C57BL/6 mice and homozygous B-hTSLP/hTSLPR mice. Mouse Tslpr mRNA was only detectable in wild type C57BL/6 mice. Human TSLPR mRNA was only detectable in homozygous B-hTSLP/hTSLPR mice but not in wild type mice.
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Protein expression analysis-TSLP
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Strain specific TSLP expression analysis in homozygous B-hTSLP/hTSLPR mice by ELISA. Calcipotriol (MC903) was dissolved in ethanol and topically applied on ears of either wild type C57BL/6 mice (+/+;+/+) or homozygous B-hTSLP/hTSLPR mice (H/H;H/H) for 7 days. n=3. Ear grinding supernatant from the two mice was analyzed by ELISA. Mouse TSLP was detectable in wild type C57BL/6 mice. Human TSLP was exclusively detectable in homozygous B-hTSLP/hTSLPR mice but not in wild type mice. ND: not detectable.
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Protein expression analysis-TSLPR in macrophages
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Strain specific TSLPR expression analysis in heterozygous B-hTSLP/hTSLPR mice by flow cytometry. Macrophages were collected from wild type C57BL/6 mice (+/+;+/+) and heterozygous B-hTSLP/hTSLPR mice (H/+;H/+), and analyzed by flow cytometry with species-specific anti-TSLPR antibody. Mouse TSLPR was detectable in wild type C57BL/6 mice and heterozygous B-hTSLP/hTSLPR mice. Human TSLPR was detectable in heterozygous B-hTSLP/hTSLPR mice but not in wild type mice.
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Protein expression analysis-TSLPR in DCs
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Strain specific TSLPR expression analysis in heterozygous B-hTSLP/hTSLPR mice by flow cytometry. Dendritic cells were induced from bone marrow of wild type C57BL/6 mice (+/+;+/+) and heterozygous B-hTSLP/hTSLPR mice (H/+;H/+), and stimulated with LPS. Protein expression was analyzed by flow cytometry with species-specific anti-TSLPR antibodies. Mouse TSLPR was detectable in wild type C57BL/6 mice and heterozygous B-hTSLP/hTSLPR mice. Human TSLPR was exclusively detectable in heterozygous B-hTSLP/hTSLPR mice but not in wild type mice.
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Protein expression analysis-TSLPR
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Human TSLPR expression analysis in homozygous B-hTSLP/hTSLPR mice by flow cytometry. Splenocytes were collected from wild type C57BL/6 mice and homozygous B-hTSLP/hTSLPR mice, and analyzed by flow cytometry with species-specific anti-TSLPR antibody. Human TSLPR was detectable on total spenocytes, CD11b+ cells (monocytes and neutrophils) and CD11c+ cells (DCs) of homozygous B-hTSLP/hTSLPR mice but not on those cells of wild type C57BL/6 mice.
Human TSLPR expression analysis in homozygous B-hTSLP/hTSLPR mice by flow cytometry. Splenocytes were collected from wild type C57BL/6 mice and homozygous B-hTSLP/hTSLPR mice, and analyzed by flow cytometry with species-specific anti-TSLPR antibody. Human TSLPR was detectable on cDC2, mo-DC, cDC1 and pre-DC of homozygous B-hTSLP/hTSLPR mice but not on those cells of wild type C57BL/6 mice.
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TSLPR protein expression analysis in T cells and ILC2 of blood
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Human TSLPR expression analysis on T cells and ILC2 of homozygous B-hTSLP/hTSLPR mice by flow cytometry. Blood cells were collected from wild-type C57BL/6 mice (+/+;+/+) and homozygous B-hTSLP/hTSLPR mice (H/H;H/H), and analyzed by flow cytometry with species-specific anti-TSLPR antibody. Mouse TSLPR was detectable on T cells and ILC2 of wild-type C57BL/6 mice but not in homozygous B-hTSLP/hTSLPR mice. Human TSLPR was exclusively detectable on the two cells of homozygous B-hTSLP/hTSLPR mice.
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Functional analysis
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Mouse TARC was induced with human TSLP and mouse TSLP in homozygous B-hTSLP/hTSLPR mice analyzed by ELISA. Dendritic cells were respectively induced with FLT3L from bone marrow of homozygous B-hTSLP/hTSLPR mice (H/H;H/H) and wild-type C57BL/6 mice (+/+;+/+), and stimulated with human TSLP or mouse TSLP in vitro. Concentration of mouse TARC secreted from DCs was assayed by ELISA. Mouse TARC was successfully induced with human TSLP, but not mouse TSLP in homozygous B-hTSLP/hTSLPR mice. Meanwhile mouse TARC was successfully induced with mouse TSLP, but not human TSLP in wild-type C57BL/6 mice. Results indicated that TSLP and TSLPR are not cross-reactive between mouse and human. Introduction of human TSLP and TSLPR genes in place of its mouse counterpart does not change the stimulation effect of TSLP on dendritic cells.
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Analysis of leukocytes cell subpopulation in spleen
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Analysis of spleen leukocyte subpopulations by FACS. Splenocytes were isolated from female C57BL/6 and B-hTSLP/hTSLPR mice (n=3, 8-week-old). Flow cytometry analysis of the splenocytes was performed to assess leukocyte subpopulations. A. Representative FACS plots. Single live cells were gated for the CD45+ population and used for further analysis as indicated here. B. Results of FACS analysis. Percent of T cells, B cells, NK cells, dendritic cells, granulocytes, monocytes and macrophages in homozygous B-hTSLP/hTSLPR mice were similar to those in the C57BL/6 mice, demonstrating that hTSLP/hTSLPR humanized does not change the overall development, differentiation or distribution of these cell types in spleen. Values are expressed as mean ± SEM.
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Analysis of T cell subpopulation in spleen
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Analysis of spleen T cell subpopulations by FACS. Splenocytes were isolated from female C57BL/6 and B-hTSLP/hTSLPR mice (n=3, 8-week-old). Flow cytometry analysis of the splenocytes was performed to assess leukocyte subpopulations. A. Representative FACS plots. Single live CD45+ cells were gated for TCRβ+ T cell population and used for further analysis as indicated here. B. Results of FACS analysis. The percent of CD4+ T cells, CD8+ T cells and Tregs in homozygous B-hTSLP/hTSLPR mice were similar to those in the C57BL/6 mice, demonstrating that introduction of hTSLP/hTSLPR in place of its mouse counterpart does not change the overall development, differentiation or distribution of these T cell subtypes in spleen. Values are expressed as mean ± SEM.
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Analysis of leukocytes cell subpopulation in bone marrow
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Analysis of leukocyte subpopulations in bone marrow by FACS. Bone marrow was isolated from female C57BL/6 and B-hTSLP/hTSLPR mice (n=3, 8-week-old). Flow cytometry analysis of the cells was performed to assess leukocyte subpopulations. A. Representative FACS plots. Single live cells were gated for the CD45+ population and used for further analysis as indicated here. B. Results of FACS analysis. Percent of T cells, B cells, NK cells, dendritic cells, granulocytes, monocytes and macrophages in homozygous B-hTSLP/hTSLPR mice were similar to those in the C57BL/6 mice, demonstrating that hTSLP/hTSLPR humanized does not change the overall development, differentiation or distribution of these cell types in bone marrow. Values are expressed as mean ± SEM.
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Analysis of leukocytes cell subpopulation in thymus
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Analysis of leukocyte subpopulations in thymus by FACS. Thymus was isolated from female C57BL/6 and B-hTSLP/hTSLPR mice (n=3, 8-week-old). Flow cytometry analysis of the cells was performed to assess leukocyte subpopulations. A. Representative FACS plots. Single live cells were gated for the CD45+ population and used for further analysis as indicated here. B. Results of FACS analysis. Percent of T cells, B cells, NK cells, dendritic cells, granulocytes, monocytes and macrophages in homozygous B-hTSLP/hTSLPR mice were similar to those in the C57BL/6 mice, demonstrating that hTSLP/hTSLPR humanized does not change the overall development, differentiation or distribution of these cell types in thymus. Values are expressed as mean ± SEM.
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Analysis of T cell subpopulation in thymus
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Analysis of T cell subpopulations in thymus by FACS. Leukocytes were isolated from female C57BL/6 and B-hTSLP/hTSLPR mice (n=3, 8-week-old). Flow cytometry analysis of the leukocytes was performed to assess leukocyte subpopulations. A. Representative FACS plots. Single live CD45+ cells were gated for TCRβ+ T cell population and used for further analysis as indicated here. B. Results of FACS analysis. The percent of CD4+ T cells, CD8+ T cells, and Tregs in homozygous B-hTSLP/hTSLPR mice were similar to those in the C57BL/6 mice, demonstrating that introduction of hTSLP/hTSLPR in place of its mouse counterpart does not change the overall development, differentiation or distribution of these T cell subtypes in thymus. Values are expressed as mean ± SEM.
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Analysis of leukocytes cell subpopulation in blood
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Analysis of blood leukocyte subpopulations by FACS. Blood cells were isolated from female C57BL/6 and B-hTSLP/hTSLPR mice (n=3, 8-week-old). Flow cytometry analysis of the blood cells was performed to assess leukocyte subpopulations. A. Representative FACS plots. Single live cells were gated for the CD45+ population and used for further analysis as indicated here. B. Results of FACS analysis. Percent of T cells, B cells, NK cells, dendritic cells, granulocytes, monocytes and macrophages in homozygous B-hTSLP/hTSLPR mice were similar to those in the C57BL/6 mice, demonstrating that hTSLP/hTSLPR humanized does not change the overall development, differentiation or distribution of these cell types in blood. Values are expressed as mean ± SEM.
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Analysis of T cell subpopulation in blood
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Analysis of blood T cell subpopulations by FACS. Blood cells were isolated from female C57BL/6 and B-hTSLP/hTSLPR mice (n=3, 8-week-old). Flow cytometry analysis of the blood cells was performed to assess leukocyte subpopulations. A. Representative FACS plots. Single live CD45+ cells were gated for TCRβ+ T cell population and used for further analysis as indicated here. B. Results of FACS analysis. The percent of CD4+ T cells, CD8+ T cells, and Tregs in homozygous B-hTSLP/hTSLPR mice were similar to those in the C57BL/6 mice, demonstrating that introduction of hTSLP/hTSLPR in place of its mouse counterpart does not change the overall development, differentiation or distribution of these T cell subtypes in blood. Values are expressed as mean ± SEM.
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Blood routine test
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Complete blood count (CBC). Blood from female C57BL/6 and B-hTSLP/hTSLPR mice (n=8, 10-11-week-old) was collected and analyzed for CBC. The measurements of B-hTSLP/hTSLPR mice were similar to that in C57BL/6 mice, indicating that introduction of hTSLP/hTSLPR in place of its mouse counterpart does not change blood cell composition and morphology. Values are expressed as mean ± SEM.
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Blood chemistry
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Blood chemistry tests of B-hTSLP/hTSLPR mice. Serum from the C57BL/6 and B-hTSLP/hTSLPR mice (n=8, 10-11-week-old) was collected and analyzed for levels of indicators. The measurements of B-hTSLP/hTSLPR mice were similar to that in C57BL/6 mice, indicating that introduction of hTSLP/hTSLPR in place of its mouse counterpart does not change the health of related organs. Values are expressed as mean ± SEM.
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Growth curve
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Body weight growth curve of B-hTSLP/hTSLPR mice after birth. Newborn pups (30 males and 30 females, respectively) were obtained at weaning (Week 3; birth date +/- 3 days). Body weight was measured once every week (on the same day each week) for 9 weeks.
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Experimental schedule for Induction of AD-like skin lesions and in vivo efficacy of anti-human TSLP antibody
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Experimental schedule for Induction of atopic dermatitis (AD)-like skin lesions and in vivo efficacy of anti-human TSLP antibody. OXA was applied to ear skin of mice on day 0, and then challenge to the same site of skin nine times from days 7 to 25. Anti-human TSLP antibody tezepelumab (in house) was administered by intraperitoneal injection (n = 8). OXA: oxazolone.
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In vivo efficacy of anti-human TSLP antibody in OXA induced AD-like mouse model
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Efficacy of anti-human TSLP antibody in B-hTSLP/hTSLPR mice. Mice in each group were treated with anti-hTSLP antibody tezepelumab (in house). (A) Statistical analysis of ear thickness in each group. Epidermis of ear began to desquamate from day 18. So the ear thicknesses were decreased from day 18 as shown in figure. (B) Body weight changes during the treatment. (C) Total IgE levels in serum. Serum was collected on day 26 and total IgE levels were measured by ELISA. (n = 8).
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H&E staining of ear skin in AD-like mouse model of B-hTSLP/hTSLPR mice
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Effects of anti-human TSLP antibody on ear skin of the AD mouse model. (A) Hematoxylin and eosin (H&E) staining. (B) Thickness of ear epidermal skin. (C) Score of eosinophils infiltrated in ear epidermal skin. (D) Total score of ear epidermal skin. Ear thickness and infiltration scores of eosinophils in ear skin of the groups treated with dexamethasone or tezepelumab were decreased significantly compared to that in the isotype control, demonstrating that the B-hTSLP/hTSLPR mice provide a powerful preclinical model for in vivo evaluation of anti-human TSLP antibodies. Infiltration score of eosinophils: 1=slight; 2=mild; 3=moderate; 4=severe. The content of the pathology total score evaluation includes the following aspects: epidermal hyperplasia in skin, erosion/crusting, hyperkeratosis and parakeratosis; inflammatory cell infiltration in dermis and subcutaneous. AD: Atopic dermatitis.
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In vivo efficacy of anti-human TSLP antibody in mouse asthma model
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Analysis of inflammatory cells in BALF by FACS.
Mouse asthma model was induced in B-hTSLP/hTSLPR mice and treated with anti-human TSLP antibody (tezepelumab, synthesized in house). BALF was collected at the end of the experiment to detect infiltrated inflammatory cells in lung tissue. The results showed that CD45+ cells, eosinophils and neutrophils in the modeling group treated with isotype antibody (G2) was significantly higher than that in the non-modeling group (G1), while these cells in the groups (G3, G4) treated with anti-human TSLP antibody decreased significantly when compared with the G2 group. Values are expressed as mean ± SEM.
OVA specific IgE in serum and TARC in BALF were significantly reduced in the mouse asthma model treated with anti-TSLP antibody.
Serum was collected at the study endpoint. IgE and TARC levels were analyzed by ELISA. The results showed that the levels of OVA specific IgE and TARC in mice treated with tezepelumab (in house) was lower than that in untreated mice. Values are expressed as mean ± SEM. TARC: thymic and activating regulatory chemokine, also known as CCL17 (C-C motif chemokine ligand 17).
H&E staining of asthma-like model in B-hTSLP/hTSLPR mice.
Lung tissues were collected at the study endpoint and analyzed with H&E staining. The results showed that when compared to the non-modeling group (G1), there was a significant increase in inflammatory cell infiltration and mucus secretion in the lung tissue of the modeling mice that were treated with isotype antibody (G2). But when compared with the isotype antibody treated group (G2), there is a significant reduction in inflammatory cell infiltration and mucus secretion in the lung tissue of the groups treated with tezepelumab (in house) (G3,G4). The results indicate that B-hTSLP/hTSLPR mice can successfully establish a mouse asthma-like model and provide a powerful preclinical model for in vivo evaluation of anti-human TSLP antibodies. Bold arrow: mucus; Narrow arrow: inflammatory cells; Triangle: eosinophils. Values are expressed as mean ± SEM.
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Summary
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- mRNA expression analysis:
Mouse Tslp and Tslpr mRNA were only detectable in wild type C57BL/6 mice. Human TSLP and TSLPR mRNA were only detectable in homozygous B-hTSLP/hTSLPR mice but not in wild type mice.
- Protein expression analysis:
Mouse TSLP and TSLPR were detectable in wild type C57BL/6 mice. Human TSLP and TSLPR were exclusively detectable in homozygous B-hTSLP/hTSLPR mice.
- Leukocytes cell subpopulation analysis：
TSLP and TSLPR humanized does not change the overall development, differentiation or distribution of immune cell types in spleen, bone marrow, thymus and blood.
- Blood routine test：
Introduction of hTSLP/hTSLPR in place of its mouse counterpart does not change blood cell composition and morphology.
- Blood chemistry：
Introduction of hTSLP/hTSLPR in place of its mouse counterpart does not change the health of related organs.
- In vivo efficacy：
Anti-human TSLP antibody was efficacious in controlling atopic dermatitis and asthma like symptoms in B-hTSLP/hTSLPR mice.
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Poster
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Functional Analysis of Anti-TSLP Antibodies Using Humanized B-hTSLP/hTSLPR Mice
