The MS4A1 gene encodes CD20. a cell surface protein predominantly expressed on B lymphocytes from the pre-B cell stage to mature B cells, but absent on plasma cells. CD20 functions as a calcium channel component, regulating B cell activation and differentiation. As a therapeutic target, CD20 is pivotal in treating B cell malignancies (e.g., non-Hodgkin's lymphoma, chronic lymphocytic leukemia) and autoimmune disorders (e.g., rheumatoid arthritis, multiple sclerosis).
MS4A1-targeting antibodies, such as rituximab, obinutuzumab, and ofatumumab, are monoclonal antibodies that bind CD20. inducing B cell depletion via mechanisms like complement-dependent cytotoxicity (CDC), antibody-dependent cellular cytotoxicity (ADCC), and direct apoptosis. Newer anti-CD20 agents (e.g., ocrelizumab) are engineered for enhanced efficacy or reduced immunogenicity.
CD20's absence on hematopoietic stem cells and plasma cells allows targeted therapy while preserving immune reconstitution capacity. However, resistance can arise from CD20 downregulation or mutations. Clinically, MS4A1 antibodies revolutionized B cell-driven disease management, balancing efficacy with manageable toxicity profiles. Additionally, CD20 serves as a diagnostic biomarker for B cell lineage classification in hematologic malignancies. Research continues to optimize dosing, combination therapies, and next-generation anti-CD20 biologics.