In accordance with the present invention, there are provided novel Down Syndrome-Cell Adhesion Molecule (DS-CAM) proteins. Nucleic acid sequences encoding such proteins and assays employing same are also disclosed. The invention DS-CAM proteins can be employed in a variety of ways, for example, for the production of anti-DS-CAM antibodies thereto, in therapeutic compositions and methods employing such proteins and/or antibodies. DS-CAM proteins are also useful in bioassays to identify agonists and antagonists thereto.
 This invention was made with Government support under Grant Numbers HL50025 and HD17449 awarded by the National Institutes of Health and DE-FG03-92ER61402 awarded by the Department of Energy. The Government has certain rights in this invention.