The invention discloses a recombinant protein (P-selectin glycoprotein ligand-1 and Neural Retina-specific Leucine Zipper) PSGL-1- NRL chimeric protein comprising a Selectin Binding domain and a non-covalent dimerization domain which is a leucine zipper and is more preferably the leucine zipper domain of the human or mouse Neural Retina-specific Leucine Zipper. The chimeric protein further comprises a covalent dimerization domain with at least one cysteine suitable to form a disulfide bridge with another chimeric protein to form a homodimer. In the chimeric protein the PSGL-1 domain corresponds to the extracellular region of Human PSGL-1 and is more preferably the selectin binding region of the mature protein. The chimeric protein is correctly post-translationally modified and is efficiently expressed in a mammalian system. It is sulfated O-linked glycosylated and sialylated and binds P E and L selectin allowing in vivo and in vitro targeting for diagnostic or therapeutic purposes.
