CD52 is present on the surface of mature lymphocytes, but not on the stem cells from which these lymphocytes were derived. It also is found on monocytes and dendritic cells. Further, it is found within the male genital tract and is present on the surface of mature sperm cells. CD52 is a peptide of 12 amino acids, anchored to glycosylphosphatidylinositol (GPI). Since it is highly negatively charged and present on sperm cells and lymphocytes, it has been conjectured that its function is anti-adhesion, allowing cells to freely move around. CD52 binds the ITIM (immunoreceptor tyrosine-based inhibitory motif)-bearing sialic acid-binding lectin SIGLEC10.