CCL22/MDC: ProductsMacrophage-derived chemokine (MDC), also named stimulated T cell chemotactic protein (STCP-1) and ABCD-1, and now designated as CCL22, is a CC chemokine initially isolated from clones of monocyte-derived macrophages. At the amino acid sequence level, MDC shows less than 35% identity to other CC chemokine family members. Human MDC is expressed in dendritic cells, macrophages and activated monocytes. In addition, MDC expression is detected in thymus, lymph node and appendix tissues. At the amino acid sequence level, mouse and human MDC share 64% identity and 83% similarity.