CD185, also known as CXCR5 or Burkitt lymphoma receptor 1 (BLR1), is a 42 kD G-protein coupled receptor with seven transmembrane regions. It belongs to the CXC chemokine receptor family and is a specific receptor for the CXC chemokine CXCL13. CD185 is expressed on mature B cells, follicular helper T cells (Tfh), and certain memory T cells. It plays a critical role in lymphocyte trafficking, particularly in the migration of T cells into B cell follicles of germinal centers, making it an established marker of follicular helper T cells. Additionally, CD185 is involved in B cell migration and maturation in lymph nodes and spleen. Its expression has been reported in various tissues, including human blood, salivary glands, and lymphatic organs.