Ms4a1 Conditional Knockout mouse models

Ms4a1, ortholog of human MS4A1, encodes CD20, a four-pass transmembrane member of the MS4A family with no identified natural ligand that associates with the B cell receptor complex and modulates store-operated calcium entry, appearing from the late pre-B stage through memory B cells and disappearing upon plasma cell differentiation. The decisive design consideration is that the null is largely uninformative, since knockout mice retain near-normal B cell development with only subtle calcium signaling changes, while the clinically meaningful biology lives entirely in the large extracellular loop that rituximab, ofatumumab and obinutuzumab recognize and that differs between mouse and human. Epitope-matched humanized CD20 knockins are therefore mandatory for studying depletion kinetics, complement-dependent cytotoxicity, antibody-dependent phagocytosis and Fc receptor engagement. Related MS4A family members are co-expressed and may buffer signaling contributions. Read out B cell depletion depth and duration across tissues, complement consumption, and recovery from bone marrow progenitors.

Conditional deletion of Ms4a1 limits the genetic change to the lineage you choose. That helps in oncology, immunology, and metabolic work where systemic loss would muddy the read. After you confirm Cre specificity, crossing to Ms4a1 floxed stock yields usable cohorts.