Biotech companies such as AnorMed Inc. and Millennium Pharmaceuticals Inc. are developing chemokine receptor inhibitors to treat a variety of diseases, including HIV and inflammatory disorders. But direct inhibition of chemokine receptors may not be "the only way to skin the cat." Last week, researchers from Washington University and colleagues reported in Nature that a protein called Slit inhibited chemokine signaling, thus opening up the possibility of new chemokine-related pathways and broadening the search for inhibitors.

Slit, a secreted protein already known to be