Generation of a Rabbit Anti‐Canine CD19 Monoclonal Antibody From Peripheral Blood and Its Validation in Immunoassays and CAR ‐T Feasibility

Lymphoma constitutes 24% of canine neoplastic diseases and 85% of haematopoietic tumours, with B-cell subtypes accounting for 60%-80% of cases. As the most prevalent spontaneous tumour in canines, this disease model holds significant translational value for human non-Hodgkin lymphoma research. To address diagnostic limitations in canine B-cell lymphoma, we developed a canine-specific CD19 monoclonal antibody (HAC19.1) with high affinity and established a dual-platform detection system compatible with flow cytometry and immunohistochemistry. Additionally, a novel CD19-targeting chimeric antigen receptor (CAR) gene sequence (HUA-1) was engineered and successfully transduced into Jurkat cells via lentiviral vectors, confirming stable CAR membrane expression. This breakthrough provides critical technical groundwork for advancing autologous CAR-T cell therapy in canines.