The molecular size is 130 kDa. The receptor belongs to the scavenger receptor cysteine rich family type B and consists of a 1048 amino acid residues extracellular domain, a single transmembrane segment and a cytoplasmic tail with several splice variants.
Clinical significance
A soluble form of the receptor exists in plasma, and cerebrospinal fluid.,[12] commonly denoted sCD163. It is generated by ectodomain shedding of the membrane bound receptor, which may represent a form of modulation of CD163 function.[13] sCD163 shedding occurs as a result of enzymatic cleavage by ADAM17.[14] sCD163 is upregulated in a large range of inflammatory diseases including liver cirrhosis,[15] type 2 diabetes, macrophage activation syndrome, Gaucher's disease, sepsis, HIV infection, rheumatoid arthritis and Hodgkin Lymphoma.[16][17] sCD163 is also upregulated in cerebrospinal fluid after subarachnoid haemorrhage.[12] CD163 has recently been identified as expressed on neurons in the CNS following hemorrhage, although the significance of this is unclear.[18][19][20] The excretion of soluble CD163 into the urine is tightly associated with the presence of active glomerulonephritis in systemic lupus erythematosus and ANCA vasculitis and can be used to track response to therapy. [21]
Differences between mouse and human
Differences between mice and humans in CD163 biology are important to note since preclinical studies are frequently conducted in mice. sCD163 shedding occurs in humans but not mice, due to the emergence of an Arg-Ser-Ser-Arg sequence in humans, essential for enzymatic cleavage by ADAM17.[22] Human CD163, but mouse CD163, exhibits a strikingly higher affinity to hemoglobin-haptoglobin complex compared to hemoglobin alone.[23]
^Droste A, Sorg C, Högger P (March 1999). "Shedding of CD163, a novel regulatory mechanism for a member of the scavenger receptor cysteine-rich family". Biochemical and Biophysical Research Communications. 256 (1): 110–3. doi:10.1006/bbrc.1999.0294. PMID10066432.
^Etzerodt A, Maniecki MB, Møller K, Møller HJ, Moestrup SK (December 2010). "Tumor necrosis factor α-converting enzyme (TACE/ADAM17) mediates ectodomain shedding of the scavenger receptor CD163". Journal of Leukocyte Biology. 88 (6): 1201–5. doi:10.1189/jlb.0410235. PMID20807704. S2CID38771947.
^Etzerodt A, Kjolby M, Nielsen MJ, Maniecki M, Svendsen P, Moestrup SK (June 2013). "Plasma clearance of hemoglobin and haptoglobin in mice and effect of CD163 gene targeting disruption". Antioxidants & Redox Signaling. 18 (17): 2254–63. doi:10.1089/ars.2012.4605. PMID22793784.
Graversen JH, Madsen M, Moestrup SK (April 2002). "CD163: a signal receptor scavenging haptoglobin-hemoglobin complexes from plasma". The International Journal of Biochemistry & Cell Biology. 34 (4): 309–14. doi:10.1016/S1357-2725(01)00144-3. PMID11854028.
Moestrup SK, Møller HJ (2005). "CD163: a regulated hemoglobin scavenger receptor with a role in the anti-inflammatory response". Annals of Medicine. 36 (5): 347–54. doi:10.1080/07853890410033171. PMID15478309. S2CID32420894.
Maruyama K, Sugano S (January 1994). "Oligo-capping: a simple method to replace the cap structure of eukaryotic mRNAs with oligoribonucleotides". Gene. 138 (1–2): 171–4. doi:10.1016/0378-1119(94)90802-8. PMID8125298.
Law SK, Micklem KJ, Shaw JM, Zhang XP, Dong Y, Willis AC, Mason DY (September 1993). "A new macrophage differentiation antigen which is a member of the scavenger receptor superfamily". European Journal of Immunology. 23 (9): 2320–5. doi:10.1002/eji.1830230940. PMID8370408. S2CID39770686.
Suzuki Y, Yoshitomo-Nakagawa K, Maruyama K, Suyama A, Sugano S (October 1997). "Construction and characterization of a full length-enriched and a 5'-end-enriched cDNA library". Gene. 200 (1–2): 149–56. doi:10.1016/S0378-1119(97)00411-3. PMID9373149.
Droste A, Sorg C, Högger P (March 1999). "Shedding of CD163, a novel regulatory mechanism for a member of the scavenger receptor cysteine-rich family". Biochemical and Biophysical Research Communications. 256 (1): 110–3. doi:10.1006/bbrc.1999.0294. PMID10066432.
Ritter M, Buechler C, Langmann T, Schmitz G (July 1999). "Genomic organization and chromosomal localization of the human CD163 (M130) gene: a member of the scavenger receptor cysteine-rich superfamily". Biochemical and Biophysical Research Communications. 260 (2): 466–74. doi:10.1006/bbrc.1999.0866. PMID10403791.
Stover CM, Schleypen J, Grønlund J, Speicher MR, Schwaeble WJ, Holmskov U (2001). "Assignment of CD163B, the gene encoding M160, a novel scavenger receptor, to human chromosome 12p13.3 by in situ hybridization and somatic cell hybrid analysis". Cytogenetics and Cell Genetics. 90 (3–4): 246–7. doi:10.1159/000056781. PMID11124526. S2CID44704901.
Sulahian TH, Hintz KA, Wardwell K, Guyre PM (June 2001). "Development of an ELISA to measure soluble CD163 in biological fluids". Journal of Immunological Methods. 252 (1–2): 25–31. doi:10.1016/S0022-1759(01)00328-3. PMID11334962.
Högger P, Sorg C (November 2001). "Soluble CD163 inhibits phorbol ester-induced lymphocyte proliferation". Biochemical and Biophysical Research Communications. 288 (4): 841–3. doi:10.1006/bbrc.2001.5845. PMID11688984.
Fonseca JE, Edwards JC, Blades S, Goulding NJ (May 2002). "Macrophage subpopulations in rheumatoid synovium: reduced CD163 expression in CD4+ T lymphocyte-rich microenvironments". Arthritis and Rheumatism. 46 (5): 1210–6. doi:10.1002/art.10207. PMID12115225.