PE anti-mouse CD93 (AA4.1, early B lineage)

CD93 is a 130-140kD C-type lectin like type I transmembrane protein, also known as complement component 1, q subcomponent (C1qR1), C1qRp collectin receptor (C1qRp), or AA4 antigen. It is a receptor expressed on immature B lymphocytes, hematopoietic progenitors and stem cells in adult bone marrow, fetal liver, embryonic yolk sac. CD93 expression level on splenic immature/transitional B cells is much lower than in bone marrow. It is reinduced during plasma cell differentiation and plays an important role in maintaining plasma cells in bone marrow niches. Immature dendritic cells express CD93 and down-regulate this molecule upon maturation, suggesting a role in uptake of particles by DC. It is also expressed on monocytes, macrophages, and endothelial cells. Macrophages from CD93 (-/-) mice had a significant phagocytic defect in the clearance of apoptotic cells in vivo, indicating CD93 may contribute to the in vivo clearance of dying cells. Binding of CD93 to C1q remains controversial.