Background:
T-cell engagers (TCEs) are bispecific antibodies that redirect T cells to kill tumor cells by simultaneously binding to the CD3ε subunit of the T cell receptor (TCR) complex and tumor-associated antigens (TAAs). CD20, a surface protein expressed on most malignant B lymphocytes, is a clinically validated target in B-cell lymphomas and autoimmune diseases. Glofitamab, a CD3/CD20 bispecific antibody, has demonstrated potent efficacy against relapsed/refractory large B-cell lymphoma. However, CD3-mediated T-cell activation can induce cytokine release syndrome (CRS), highlighting the need for robust preclinical models to evaluate both efficacy and safety. Reliable animal models are essential to support drug discovery across cancer and autoimmune indications.
Methods:
Biocytogens generated a double humanized mouse model expressing humanized CD3E, CD3D, and CD3G (CD3EDG) and human CD20 on a C57BL/6 background (B-hCD20 mice). Flow cytometry confirmed humanized CD3E expression on T calls and human CD20 expression on B cells in the spleen. T_cell killing function was demonstrated using in vitro TDCC assays. In vivo toxicity was assessed via cytokine profiling following antibody treatment. For efficacy evaluation, syngeneic tumor models were established by inoculating B-hCD3EDG/hCD20 mice with B-hCD20 MC38 cells, a CD20-humanized MC38 colon cancer cell line. A Glofitamab analog was administered to evaluate therapeutic activity in both tumor-bearing and autoimmune disease settings. Autoimmune relevance was further assessed through B-cell depletion studies and an experimental autoimmune encephalomyelitis (EAE) model induced by MOG immunization.
Results:
B-hCD3EDG/hCD20 mice exhibited expression of humanized CD3 and CD20 on T and B cells, respectively. T cells effectively killed B-hCD20 MC38 tumor cells. Toxicity studies revealed notable cytokine release in response to treatment. In the syngeneic tumor model, Gloafitabmab analog treatment significantly suppressed tumor growth. For autoimmune indications, the bispecific antibody efficiently depleted B cells in vivo. Moreover, in the EAE model, Glofitamab analog treatment alleviated neurological symptoms, supporting its therapeutic potential in autoimmune diseases.
Conclusion:
Biocytogen’s B-hCD3EDG/hCD20 mice provide a versatile and physiologically relevant models for evaluating CD30/CD20-targeted therapeutics across oncology and autoimmune indications. These models enable comprehensive pharmacological and safety assessments of bispecific antibodies, monoclonal antibodies, CAR-T cell therapies, and other CD20-directed agents, thereby supporting their translational development.
