Description: The eBioCW-1.2 monoclonal antibody reacts with mouse CCR9 (CD199), which is the receptor for thymus-expressed chemokine (TECK). CCR9 is a member of the G protein coupled receptor (GPCR) supergene family, and is involved in trafficking of T cell progenitors within the thymus. CCR9 expression during thymocyte development commences at the double-negative (DN) 3 stage (CD4-CD8-CD25+CD44-), peaks in the double-positive (DP) stage (CD4+CD8+CD25-CD44-), and is down-regulated in commited CD4+ or CD8+ single-positive (SP) thymoyctes. CCR9-deficient mice show a mild impairment in thymoycte development. In the periphery, CCR9 is thought to be expressed on naïve CD8+ T cells, but not on naïve CD4+ T cells.