• B-hCTLA4/hCCR8 mice are double gene-humanized C57BL/6 mice generated for CTLA4 and CCR8 immuno-oncology studies.
• CTLA4, also known as CD152, is an immune checkpoint receptor associated with T-cell activation and regulatory T-cell function.
• CCR8 is a chemokine receptor enriched in tumor-infiltrating Treg cells and is an important target for tumor immune microenvironment research.
• B-hCTLA4/hCCR8 mice enable in vivo evaluation of anti-human CTLA4 antibodies, anti-human CCR8 antibodies, and combination strategies in syngeneic tumor models.

Key Advantages

• Dual humanized CTLA4 and CCR8 mouse model on a C57BL/6 background
• Human CTLA4 expression validated in spleen and lymph node after anti-mouse CD3ε stimulation
• Human CTLA4 and human CCR8 expression validated in MC38 tumor-infiltrating immune cells
• Supports efficacy evaluation of anti-human CTLA4 antibody, anti-human CCR8 antibody, and combination therapy
• Useful for tumor-infiltrating Treg biology, checkpoint blockade, and CCR8-targeted immuno-oncology research

Validation

• CTLA4 Protein Validation: Human CTLA4 was detected in spleen and lymph node from homozygous B-hCTLA4/hCCR8 mice by flow cytometry after anti-mouse CD3ε stimulation.
• Tumor-Infiltrating CTLA4 Validation: Human CTLA4 was detected in T cells from MC38 tumors implanted in homozygous B-hCTLA4/hCCR8 mice.
• Tumor-Infiltrating CCR8 Validation: Human CCR8 was detected in CD4+ T cells and Treg cells from MC38 tumors in homozygous B-hCTLA4/hCCR8 mice.
• Efficacy Validation: Anti-human CTLA4 antibody, anti-human CCR8 antibody, and combination treatment inhibited MC38 tumor growth in B-hCTLA4/hCCR8 mice.

Application

• Anti-human CTLA4 antibody efficacy evaluation
• Anti-human CCR8 antibody efficacy evaluation
• CTLA4 and CCR8 combination therapy studies
• MC38 syngeneic tumor pharmacology studies
• Tumor-infiltrating Treg and immune checkpoint biology research
• Preclinical immuno-oncology drug development

In B-hCTLA4/hCCR8 mice, exon 2 of the mouse Ctla4 gene encoding the extracellular domain was replaced by human CTLA4 exon 2. In the same B-hCTLA4/hCCR8 mice model, exon 2 of the mouse Ccr8 gene encoding the full coding sequence was replaced by exon 2 of the human CCR8 gene. This targeting strategy supports human CTLA4 and human CCR8 expression in an immunocompetent C57BL/6 background for antibody efficacy and tumor immune microenvironment studies.

CTLA4 (CD152) protein expression analysis in B-hCTLA4/hCCR8 mice by FACS. Spleen was collected from wild-type mice and homozygous B-hCTLA4/hCCR8 mice stimulated with anti-mouse CD3ε antibody (7.5 μg, i.p.) in vivo for 24 hrs. Protein expression was analyzed with anti-mouse CTLA4 antibody (BioLegend, 106310) and anti-human CTLA4 antibody (BioLegend, 349906) by flow cytometry. Human CTLA4 was detectable in homozygous B-hCTLA4/hCCR8 mice but not in wild-type mice.

Human CTLA4 (CD152) protein expression analysis in B-hCTLA4/hCCR8 mice by FACS. Spleen was collected from wild-type mice and homozygous B-hCTLA4/hCCR8 mice stimulated with anti-mouse CD3ε antibody (7.5 μg, i.p.) in vivo for 24 hrs. Protein expression was analyzed with anti-mouse CTLA4 antibody (BioLegend, 106310) and anti-human CTLA4 antibody (BioLegend, 349906) by flow cytometry. Human CTLA4 was detectable in homozygous B-hCTLA4/hCCR8 mice.

Human CTLA4 (CD152) protein expression analysis in B-hCTLA4/hCCR8 mice by FACS. Lymph node was collected from wild-type mice and homozygous B-hCTLA4/hCCR8 mice stimulated with anti-mouse CD3ε antibody (7.5 μg, i.p.) in vivo for 24 hrs. Protein expression was analyzed with anti-mouse CTLA4 antibody (BioLegend, 106310) and anti-human CTLA4 antibody (BioLegend, 349906) by flow cytometry. Human CTLA4 was detectable in homozygous B-hCTLA4/hCCR8 mice but not in wild-type mice.

Human CTLA4 (CD152) protein expression analysis in B-hCTLA4/hCCR8 mice by FACS. Lymph node was collected from wild-type mice and homozygous B-hCTLA4/hCCR8 mice stimulated with anti-mouse CD3ε antibody (7.5 μg, i.p.) in vivo for 24 hrs. Protein expression was analyzed with anti-mouse CTLA4 antibody (BioLegend, 106310) and anti-human CTLA4 antibody (BioLegend, 349906) by flow cytometry. Human CTLA4 was detectable in homozygous B-hCTLA4/hCCR8 mice.

Human CTLA4 (CD152) protein expression analysis in B-hCTLA4/hCCR8 mice by FACS. Murine colon cancer MC38 cells were subcutaneously implanted into homozygous B-hCTLA4/hCCR8 mice. Tumors were harvested at approximately 400-700 mm^3 and analyzed with anti-mouse CTLA4 antibody (BioLegend, 106312) and anti-human CTLA4 antibody (BioLegend, 349906) by flow cytometry. Human CTLA4 was detectable in T cells in tumors of homozygous B-hCTLA4/hCCR8 mice.

Human CCR8 (CD198) protein expression analysis in B-hCTLA4/hCCR8 mice by FACS. Murine colon cancer MC38 cells were subcutaneously implanted into homozygous B-hCTLA4/hCCR8 mice. Tumors were harvested at approximately 400-700 mm^3 and analyzed by flow cytometry. Human CCR8 was detectable in CD4+ T cells and Treg cells in tumors of homozygous B-hCTLA4/hCCR8 mice.

Antitumor activity of anti-human CCR8 antibody or anti-human CTLA4 antibody in B-hCTLA4/hCCR8 mice. 
Anti-human CCR8 antibody, anti-human CTLA4 antibody, or the combination inhibited MC38 tumor growth in B-hCTLA4/hCCR8 mice. MC38 cells were subcutaneously implanted into homozygous B-hCTLA4/hCCR8 mice. Mice were grouped when tumor volume reached approximately 80 mm^3 and treated as indicated. Body weight changes were monitored. All data was provided by the client.

Q1: What are B-hCTLA4/hCCR8 mice?

B-hCTLA4/hCCR8 mice are gene-humanized mice developed by Biocytogen for human target expression, pharmacology studies, and preclinical efficacy evaluation.

Q2: Why are B-hCTLA4/hCCR8 mice useful?

B-hCTLA4/hCCR8 mice combine humanized CTLA4 and CCR8 targets, supporting studies of checkpoint blockade, CCR8-positive Treg cells, and combination immuno-oncology therapies.

Q3: How was human CTLA4 expression validated?

Human CTLA4 expression was validated in spleen, lymph node, and tumor-infiltrating T cells, while human CCR8 expression was validated in tumor-infiltrating CD4+ T cells and Treg cells.