Ly6G is a GPI-anchored protein, that is also known as the myeloid differentiation antigen Gr1. The antigen is transiently expressed on monocytes in the bone marrow. The level of antigen expression in the bone marrow directly correlates with granulocyte differentiation and maturation. Ly6G is expressed predominantly on neutrophils, also in a subset of eosinophils, differentiating pre-monocytes, and plasmacytoid dendritic cells.