Description: The M1/69 monoclonal antibody reacts with the mouse CD24 molecule, also known as Heat Stable Antigen （HSA）. This 35-50 kDa molecule is anchored in the plasma membrane via phosphatidylinositol and is expressed by erythrocytes, thymocytes, peripheral lymphocytes and myeloid lineage. CD24 is a variably glycosylated molecule resulting in heterogeneity of molecular mass of this antigen on cells of different lineages and antibodies to CD24 exhibit subtle differences in staining level on lymphocyte populations. The expression of CD24 has been used to resolve stages of B lymphopoiesis in mouse bone marrow. It has been reported that P-selectin （CD62P） binds to CD24.