CD19
OVERVIEW
CD19 is a transmembrane protein found on the cell surface that is involved in establishing intrinsic B cell signaling thresholds through the modulation of both B cell receptor (BCR)-dependent and -independent signaling.1
CD19 is thought to play dual roles in B cell activation:
- As an adaptor protein to recruit cytoplasmic signaling proteins to the membrane
- As a signal subunit for the CD19/CD21 complex when bound with the BCR, where antigen-bearing complement enhances B-cell activation via BCR-CD19/CD21 binding
CD19 also has other roles such aiding in the regulation of bone marrow development; it also plays a role in B cell development from early differentiation events in the bone marrow to late maturation steps in the spleen. CD19 signaling may play a role in controlling the progression of early pre-B to small, resting pre-B cells in the bone marrow by associating with components of the pre-BCR.
IMPLICATIONS IN CANCER
Though it is not known if CD19 direcyly contributes to B cell carcinogenesis, its expression is highly conserved on most B cell tumors. It is expressed at normal to high rates in many malignancies:1
- 80% of acute lymphoblastic leukemias
- 88% of B-cell lymphomas
- 100% of B cell leukemias
CD19 is an essential marker for B-cell proliferation and has high expression across B-cell malignancies including diffuse large B-cell lymphoma (DLBCL), follicular lymphoma (FL), and chronic lymphocytic leukemia (CLL).2
Related Research
- Wang K, Wei G, Liu D. CD19: a biomarker for B cell development, lymphoma diagnosis and therapy. Exp Hematol Oncol. 2012;1(1):1-7.
- Levy M, et al. A first-in-human phase 1 study of ABBV-319, an antibody-drug conjugate composed of a CD19 antibody linked to a potent propriety glucocorticosteroid, in patients with relapsed or refractory B-cell malignancies. Poster 1625 presented at: 64th ASH. December 10-13, 2022. New Orleans, LA.
