The mouse Cd155 gene was replaced by human CD155 coding sequence in B-hCD155 MC38 cells. Human CD155 is highly expressed on the surface of B-hCD155 MC38 cells.

Gene targeting strategy for B-hCD155 MC38 cells. The exogenous promoter and human CD155 coding sequence were inserted to replace part of murine exon 2-3. The insertion disrupts the endogenous murine Cd155 gene, resulting in a non-functional transcript.

CD155 expression analysis in B-hCD155 MC38 cells by flow cytometry. Single cell suspensions from wild-type MC38 and B-hCD155 MC38 cultures were stained with species-specific anti-CD155 antibody. Human CD155 was detected on the surface of B-hCD155 MC38 cells but not wild-type MC38 cells. The 3-B8 clone of B-hCD155 MC38 cells was used for in vivo experiments.

Subcutaneous homograft tumor growth of B-hCD155 MC38 cells. B-hCD155 MC38 cells (1x10⁷) and wild-type MC38 cells (5x10⁵) were subcutaneously implanted into B-hTIGIT mice (female, 7-week-old, n=5). 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 × long diameter × short diameter². As shown in panel A, B-hCD155 MC38 cells were able to establish tumors in vivo and can be used for efficacy studies.

B-hCD155 MC38 cells were subcutaneously transplanted into B-hTIGIT mice (n=5). At the end of the experiment, tumor cells were harvested and assessed for human CD155 expression by flow cytometry. As shown, human CD155 was highly expressed on the surface of tumor cells. Therefore, B-hCD155 MC38 cells can be used for in vivo efficacy studies of novel CD155 therapeutics.