The mouse Ceacam1 gene was replaced by human CEACAM1 coding sequence in B-hCEACAM1 MC38 cells. Human CEACAM1 is highly expressed on the surface of B-hCEACAM1 MC38 cells.

Gene targeting strategy for B-hCEACAM1 MC38 cells. The exogenous promoter and human CEACAM1 coding sequence was inserted to replace part of murine exon 2. The insertion disrupts the endogenous murine Ceacam1 gene, resulting in a non-functional transcript.

CEACAM1 expression analysis in B-hCEACAM1 MC38 cells by flow cytometry. Single cell suspensions from wild-type MC38 and B-hCEACAM1 MC38 cultures were stained with species-specific anti-CEACAM1 antibody. Mouse CEACAM1 was detectable in wild-type MC38 cells. Human CEACAM1 was detected on the surface of B-hCEACAM1 MC38 cells but not wild-type MC38 cells. The D1 clone of B-hCEACAM1 MC38 cells was used for in vivo experiments.

Subcutaneous homograft tumor growth of B-hCEACAM1 MC38 cells. B-hCEACAM1 MC38 cells (5x10⁵) were subcutaneously implanted into C57BL/6 mice (female, 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-hCEACAM1 MC38 cells were able to establish tumors in vivo and can be used for efficacy studies.

B-hCEACAM1 MC38 tumor growth of individual mice. B-hCEACAM1 MC38 cells (5x10⁵) were subcutaneously implanted into C57BL/6 mice (female, n=5). As shown in panel, B-hCEACAM1 MC38 cells were able to establish tumors in vivo and can be used for efficacy studies.