The mouse Cd19 gene was replaced by human CD19 coding sequence in B-hCD19 EL4 cells. Human CD19 is highly expressed on the surface of B-hCD19 EL4 cells.

Gene targeting strategy for B-hCD19 EL4 cells.
The exogenous promoter and human CD19 coding sequence were inserted to replace part of murine exons 2-12. The insertion disrupts the endogenous murine CD19 gene, resulting in a non-functional transcript.

Subcutaneous homograft tumor growth of B-hCD19 EL4 cells.
B-hCD19 EL4 cells (2x10⁵) and wild-type EL4 cells (2x10⁵) were subcutaneously implanted into C57BL/6 mice (female, 5-8-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-hCD19 EL4 cells were able to establish tumors in vivo and can be used for efficacy studies.