B-hIL2RB/hIL2RG mice

Basic Information

Targeting strategy

Gene targeting strategy for B-hIL2RB/hIL2RG mice. The exons 2~8 of mouse Il2rb gene that encodes the extracellular domain were replaced by human IL2RB exons 2~8 in B-hIL2RB/IL2RG mice. The exons 1~8 of mouse Il2rg gene that encodes the full-coding region sequences were replaced by human IL2RG exons 1~8 in B-hIL2RB/IL2RG mice.

Protein expression analysis of T cells

Strain specific IL2RB and IL2RG expression analysis in heterozygous and homozygous B-hIL2RB/hIL2RG mice by flow cytometry. Splenocytes were collected from wild-type mice and B-hIL2RB/hIL2RG mice, and analyzed by flow cytometry with species-specific antibody. Human IL2RB was detectable in heterozygous (H/+;H/+) and homozygous B-hIL2RB/hIL2RG mice (H/H;H/H). Human IL2RG was too low to detectable in heterozygous, but detectable in homozygous B-hIL2RB/hIL2RG mice.

Protein expression analysis of NK cells

Strain specific IL2RB and IL2RG expression analysis in heterozygous and homozygous B-hIL2RB/hIL2RG mice by flow cytometry. Splenocytes were collected from wild-type mice and B-hIL2RB/hIL2RG mice, and analyzed by flow cytometry with species-specific antibody. Human IL2RB was detectable in heterozygous (H/+;H/+) and homozygous (H/H;H/H) B-hIL2RB/hIL2RG mice. Human IL2RG was too low to detectable in heterozygous mice, and it was unable to judge the IL2RG expression in NK cells, because NK cells were diminished in homozygous B-hIL2RB/hIL2RG mice.

Analysis of spleen leukocytes subpopulation in B-hIL2RB/hIL2RG mice

Analysis of spleen leukocyte subpopulations by FACS. Splenocytes were isolated from female C57BL/6 and B-hIL2RB/hIL2RG mice (n=3, 6-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. T cells, B cells and NK cells were significantly different between homozygous B-hIL2RB/hIL2RG mice and C57BL/6 mice.

Analysis of spleen T cell subpopulation in B-hIL2RB/hIL2RG mice

Analysis of spleen T cell subpopulations by FACS. Splenocytes were isolated from female C57BL/6 and B-hIL2RB/hIL2RG mice (n=3, 6-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 T cell population and used for further analysis as indicated here. B. Results of FACS analysis. The percent of CD8+ T cells, CD4+ T cells, and Tregs in homozygous B-hIL2RB/hIL2RG mice mice were similar to those in the C57BL/6 mice. Values are expressed as mean ± SEM.

Analysis of lymph node leukocytes subpopulation in B-hIL2RB/hIL2RG mice

Analysis of lymph node leukocyte subpopulations by FACS. Leukocytes were isolated from female C57BL/6 and B-hIL2RB/hIL2RG mice (n=3, 6-week-old). Flow cytometry analysis of the leukocytes was performed to assess leukocyte subpopulations. A. Representative FACS plots. Single live cells were gated for CD45+ population and used for further analysis as indicated here. B. Results of FACS analysis. The percent of T cells, B cells, NK cells, in homozygous B-hIL2RB/hIL2RG mice were similar to those in the C57BL/6 mice. Values are expressed as mean ± SEM.

Analysis of lymph node T cell subpopulation in B-hIL2RB/hIL2RG mice

Analysis of lymph node T cell subpopulations by FACS. Leukocytes were isolated from female C57BL/6 and B-hIL2RB/hIL2RG mice (n=3, 6- 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 CD8+ T cells, CD4+ T cells in homozygous B-hIL2RB/hIL2RG mice were similar to those in the C57BL/6 mice. Values are expressed as mean ± SEM.

Analysis of blood leukocytes subpopulation in B-hIL2RB/hIL2RG mice

Analysis of blood leukocyte subpopulations by FACS. Leukocytes were isolated from female C57BL/6 and B-hIL2RB/hIL2RG mice (n=3, 6-week-old). Flow cytometry analysis of the leukocytes was performed to assess leukocyte subpopulations. A. Representative FACS plots. Single live cells were gated for CD45+ population and used for further analysis as indicated here. B. Results of FACS analysis. The percent of T cells, B cells and NK cells were significantly different between homozygous B-hIL2RB/hIL2RG mice and C57BL/6 mice.

Analysis of blood T cell subpopulation in B-hIL2RB/hIL2RG mice

Analysis of blood T subpopulations by FACS. Leukocytes were isolated from female C57BL/6 and B-hIL2RB/hIL2RG mice (n=3, 6-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+, CD8+, Tregs in homozygous B-hIL2RB/hIL2RG mice mice were similar to those in the C57BL/6 mice. Values are expressed as mean ± SEM.

Phosphorylation of STAT5 induced by human IL2 and complex of IL15/IL15RA

 

Phosphorylation of STAT5 induced by human IL2 and complex of IL15/IL15RA

Intracellular pSTAT5 analysis in spleen T cells of B-hIL2RB/hIL2RG mice by flow cytometry. Splenocytes were collected from wild-type C57BL/6 mice, homozygous and heterozygous B-hIL2RB/hIL2RG mice, and stimulated with IL2 or complex of IL15/IL15RA in vitro for 30 min. Then analyzed by flow cytometry with anti-pSTAT5 antibodies. Human IL2 induced a low phosphorylation level of STAT5 in C57BL/6 mice compared with humanized mice. As for the IL15/IL15RA complex, both mouse and human complex can induce the pSTAT5, but the mouse complex results low in homozygous mice. Above all, the IL2RB and IL2RG humanization did not change the signaling pathway.

In vivo efficacy of IL2 analogs

Antitumor activity of IL2 analogs (provided by the client) in B-hIL2RB/hIL2RG mice. (A) MC38 tumor growth. (B) Body weight changes during treatment. ​The tumor growth curve of individual mice in PBS group (C) and IL2 analogs treatment group (D). Murine colon cancer MC38 cells were subcutaneously implanted into homozygous B-hIL2RB/hIL2RG mice (female, 8 week-old, n=5). Mice were grouped when tumor volume reached approximately 100 mm³, at which time they were treated with IL2 analogs (red arrows). As shown in panel, IL2 analogs were efficacious in controlling tumor growth but causing some toxic, resulting decrease of body weight and some mice dying. B-hIL2RB/hIL2RG mice provide a powerful preclinical model for in vivo evaluation of IL2 therapy molecules. Values are expressed as mean ± SEM.

Tumor growth curve of B-hMSLN MC38 cells

Subcutaneous homograft tumor growth of B-hMSLN MC38 cells. B-hMSLN MC38 cells were subcutaneously implanted into homozygous B-hIL2RB/hIL2RG mice (female, 7-week-old, n=6). Tumor volume and body weight were measured twice a week. (A) Average tumor volume ± SEM. (B)  Body weight (Mean± SEM). Volume was expressed in mm³ using the formula: V=0.5 X long diameter X short diameter². As shown in panel A, B-hMSLN MC38 cells were able to establish tumors in vivo and can be used for efficacy studies.

Tumor growth curve of B-hHER2 MC38 cells

Subcutaneous homograft tumor growth of B-hHER2 MC38 cells. B-hHER2 MC38 cells were subcutaneously implanted into homozygous B-hIL2RB/hIL2RG mice (female, 7-week-old, n=6). Tumor volume and body weight were measured twice a week. (A) Average tumor volume ± SEM. (B)  Body weight (Mean± SEM). Volume was expressed in mm³ using the formula: V=0.5 X long diameter X short diameter². As shown in panel A, B-hHER2 MC38 cells were able to establish tumors in vivo and can be used for efficacy studies.

Protein expression analysis of tumor cells

Tumor cells were harvested and assessed for human MSLN or HER2 expression by flow cytometry. As shown, human MSLN was highly expressed on the surface of B-hMSLN MC38 tumor cells, and human HER2 was highly expressed on the surface of B-hHER2 MC38 tumor cells.