Gene targeting strategy for B-hIL34 MC38 cells. The exogenous promoter and human IL34 coding sequence was inserted to replace part of murine exon 3 and all of exon 4 and exon 5. The insertion disrupts the endogenous murine Il34 gene, resulting in a non-functional transcript.

IL34 expression analysis in B-hIL34 MC38 cells by ELISA. Single cell suspensions from wild-type MC38 and B-hIL34 MC38 cultures were stained with species-specific anti-IL34 antibody. Human IL34 was detectable in the suspensions of B-hIL34 MC38 cells but not in wild-type MC38 cells. The 1-D08 clone of B-hIL34 MC38 cells was used for in vivo experiments.

Subcutaneous homograft tumor growth of B-hIL34 MC38 cells. B-hIL34 MC38 cells (5x10⁵) and wild-type MC38 cells (5x10⁵) were subcutaneously implanted into C57BL/6N mice (female, 9-week-old). 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-hIL34 MC38 cells were able to establish tumors in vivo and can be used for efficacy studies.