Figure 1. Gene knock-in strategy to engineer a mouse model expressing a chimeric human-murine 4-1BB (also called CD137, TNFRSF9) gene. The endogenous mouse Tnfrsf9 gene was replaced with a human TNFRSF9 extracellular and mouse Tnfrsf9 transmembrane-intracellular (cytoplasmic) region downstream of the ATG start codon.
4-1BB (CD137) Expression in Humanized Mouse Model
Figure 2. Flow cytometric analysis of pan T cells isolated from male heterozygous humanized 4-1BB mice (hCD137+/-). Male spleen pan T cells were isolated and stimulated with 1µg/mL of anti-CD3 and 1µg/mL of anti-CD28 for 48 hours. The cells were stained with anti-hCD137-APC, mCD137-PE, mCD3-V450 and mCD8-FITC for flow cytometry analysis. Results showed that human 4-1BB (hCD137) was expressed in both activated CD4+ and CD8+ lymphocytes.