Used in research and development of targeted cancer therapies, particularly in B-cell malignancies such as non-Hodgkin’s lymphoma and acute lymphoblastic leukemia. Serves as a reference standard in analytical studies to evaluate binding affinity, specificity, and functional activity of experimental anti-CD19 antibodies. Employed in flow cytometry, immunohistochemistry, and cell-based assays to detect CD19 expression on B cells. Supports the calibration of therapeutic antibody production and biosimilar development. Also utilized in pharmacokinetic and pharmacodynamic studies to compare clinical performance across anti-CD19 drug candidates.