C-X-C chemokine receptor type 5 (CXC-R5) also known as CD185 (cluster of differentiation 185) or Burkitt lymphoma receptor 1 (BLR1) is a G protein-coupled seven transmembrane receptor for chemokine CXCL13 (also known as BLC) and belongs to the CXC chemokine receptor family. It enables T cells to migrate to lymph node B cell zones. In humans, the CXC-R5 protein is encoded by the CXCR5gene.
The BLR1 / CXCR5gene is specifically expressed in Burkitt's lymphoma and lymphatic tissues, such as follicles in lymph nodes as well as in spleen. The gene plays an essential role in B cell migration. Recently, it was shown that CXCR5 overexpression in breast cancer patients highly correlates with lymph node metastases, and elevated CXCR5 expression may contribute to abnormal cell survival and migration in breast tumors that lack functional p53 protein. Minor allele of SNP rs630923, located in the area of CXCR5 gene promoter and associated with the risk of multiple sclerosis, is responsible for appearance of MEF2C-binding site resulted in reduced CXCR5 gene promoter activity in B-cells during activation, that could lead to decreased autoimmune response 
^Dobner T, Wolf I, Emrich T, Lipp M (November 1992). "Differentiation-specific expression of a novel G protein-coupled receptor from Burkitt's lymphoma". European Journal of Immunology. 22 (11): 2795–9. doi:10.1002/eji.1830221107. PMID1425907.
^Förster R, Mattis AE, Kremmer E, Wolf E, Brem G, Lipp M (December 1996). "A putative chemokine receptor, BLR1, directs B cell migration to defined lymphoid organs and specific anatomic compartments of the spleen". Cell. 87 (6): 1037–47. doi:10.1016/S0092-8674(00)81798-5. PMID8978608.
^Biswas S, Sengupta S, Roy Chowdhury S, Jana S, Mandal G, Mandal PK, Saha N, Malhotra V, Gupta A, Kuprash DV, Bhattacharyya A (January 2014). "CXCL13-CXCR5 co-expression regulates epithelial to mesenchymal transition of breast cancer cells during lymph node metastasis". Breast Cancer Res Treat. 143 (2): 265–76. doi:10.1007/s10549-013-2811-8. PMID24337540.
^Mitkin NA, Hook CD, Schwartz AM, Biswas S, Kochetkov DV, Muratova AM, Afanasyeva MA, Kravchenko JE, Bhattacharyya A, Kuprash DV (March 2015). "p53-dependent expression of CXCR5 chemokine receptor in MCF-7 breast cancer cells". Sci Rep. 19 (5). doi:10.1038/srep09330. PMID25786345.
^Mitkin NA, Muratova AM, Schwartz AM, Kuprash DV (Nov 2016). "The A Allele of the Single-Nucleotide Polymorphism rs630923 Creates a Binding Site for MEF2C Resulting in Reduced CXCR5 Promoter Activity in B-Cell Lymphoblastic Cell Lines". Front. Immunol. 7 (515). doi:10.3389/fimmu.2016.00515. PMID27909439.
Gunn MD, Ngo VN, Ansel KM, Ekland EH, Cyster JG, Williams LT (February 1998). "A B-cell-homing chemokine made in lymphoid follicles activates Burkitt's lymphoma receptor-1". Nature. 391 (6669): 799–803. doi:10.1038/35876. PMID9486651.
Müller G, Lipp M (September 2001). "Signal transduction by the chemokine receptor CXCR5: structural requirements for G protein activation analyzed by chimeric CXCR1/CXCR5 molecules". Biological Chemistry. 382 (9): 1387–97. doi:10.1515/BC.2001.171. PMID11688722.
Schaerli P, Loetscher P, Moser B (December 2001). "Cutting edge: induction of follicular homing precedes effector Th cell development". Journal of Immunology. 167 (11): 6082–6. doi:10.4049/jimmunol.167.11.6082. PMID11714765.
Kim CH, Johnston B, Butcher EC (July 2002). "Trafficking machinery of NKT cells: shared and differential chemokine receptor expression among V alpha 24(+)V beta 11(+) NKT cell subsets with distinct cytokine-producing capacity". Blood. 100 (1): 11–6. doi:10.1182/blood-2001-12-0196. PMID12070001.
Battle TE, Yen A (October 2002). "Ectopic expression of CXCR5/BLR1 accelerates retinoic acid- and vitamin D(3)-induced monocytic differentiation of U937 cells". Experimental Biology and Medicine. 227 (9): 753–62. PMID12324654.
Lisignoli G, Toneguzzi S, Piacentini A, Cattini L, Lenti A, Tschon M, Cristino S, Grassi F, Facchini A (January 2003). "Human osteoblasts express functional CXC chemokine receptors 3 and 5: activation by their ligands, CXCL10 and CXCL13, significantly induces alkaline phosphatase and beta-N-acetylhexosaminidase release". Journal of Cellular Physiology. 194 (1): 71–9. doi:10.1002/jcp.10188. PMID12447991.
Chan CC, Shen D, Hackett JJ, Buggage RR, Tuaillon N (February 2003). "Expression of chemokine receptors, CXCR4 and CXCR5, and chemokines, BLC and SDF-1, in the eyes of patients with primary intraocular lymphoma". Ophthalmology. 110 (2): 421–6. doi:10.1016/S0161-6420(02)01737-2. PMID12578791.
Flynn G, Maru S, Loughlin J, Romero IA, Male D (March 2003). "Regulation of chemokine receptor expression in human microglia and astrocytes". Journal of Neuroimmunology. 136 (1-2): 84–93. doi:10.1016/S0165-5728(03)00009-2. PMID12620646.
Lisignoli G, Piacentini A, Toneguzzi S, Grassi F, Tschon M, Cristino S, Facchini A, Mariani E (2004). "Age-associated changes in functional response to CXCR3 and CXCR5 chemokine receptors in human osteoblasts". Biogerontology. 4 (5): 309–17. doi:10.1023/A:1026203502385. PMID14618028.
Aust G, Sittig D, Becherer L, Anderegg U, Schütz A, Lamesch P, Schmücking E (February 2004). "The role of CXCR5 and its ligand CXCL13 in the compartmentalization of lymphocytes in thyroids affected by autoimmune thyroid diseases". European Journal of Endocrinology / European Federation of Endocrine Societies. 150 (2): 225–34. doi:10.1530/eje.0.1500225. PMID14763921.
Steinmetz OM, Panzer U, Kneissler U, Harendza S, Lipp M, Helmchen U, Stahl RA (April 2005). "BCA-1/CXCL13 expression is associated with CXCR5-positive B-cell cluster formation in acute renal transplant rejection". Kidney International. 67 (4): 1616–21. doi:10.1111/j.1523-1755.2005.00244.x. PMID15780119.
Hu C, Xiong J, Zhang L, Huang B, Zhang Q, Li Q, Yang M, Wu Y, Wu Q, Shen Q, Gao Q, Zhang K, Sun Z, Liu J, Jin Y, Tan J (August 2004). "PEG10 activation by co-stimulation of CXCR5 and CCR7 essentially contributes to resistance to apoptosis in CD19+CD34+ B cells from patients with B cell lineage acute and chronic lymphocytic leukemia". Cellular & Molecular Immunology. 1 (4): 280–94. PMID16225771.