The CD2-subset of the Ig superfamily of cell surface molecules: receptor-ligand pairs expressed by NK cells and other immune cells

The CD2-subset of the immunoglobulin superfamily of cell surface receptors is an emerging family of proteins involved in cellular activation. Members of this family are CD2, CD48, CD58, CD84, signaling lymphocytic activation molecule (SLAM), 2B4 and Ly-9. These proteins are expressed on different leukocyte populations and the receptors of this family, specifically CD2, 2B4 and SLAM, contribute to the activation of T cells and natural killer cells. 2B4 and SLAM associate with a protein termed SLAM-associated protein that is the genetic defect in the immunodeficiency X-linked lymphoproliferative syndrome. Impaired signaling via these receptors may contribute to this often-fatal immunodeficiency.