Neural Cell Adhesion Molecule 1 (NCAM-1), a multifunctional member of the immunoglobulin superfamily, is expressed on the surfaces of neurons, glial cells, skeletal muscle, and natural killer cells. NCAM-1 plays a role in cell-cell adhesion and is crucial for the development of the nervous system. It is also involved in the expansion of T cells and dendritic cells, which are key players in immune surveillance.