title: Isolation of homologous restriction factor from human urine. Immunochemical properties and biologic activity.
abstract: A soluble form of homologous restriction factor (HRF-U) was isolated from normal human urine. With respect to m.w. (65,000) and immunoblotting characteristics, it resembled membrane HRF (HRF-M) that had been isolated from human E membranes. The protein exhibited limited cross-reactivity with the channel-forming proteins of C and cytotoxic lymphocytes. It inhibited reactive lysis of E by human C5b-9. Inhibition occurred at the attachment stage of C5b-7 to target cells, rather than at the C8 or C9 stage of membrane attack complex assembly which is inhibited by HRF-M. In this respect, HRF-U acts analogously to S protein of serum, but no immunochemical relationship between these two proteins was detected. HRF-U might be derived from the soluble HRF detected in cytoplasmic granules of killer lymphocytes.
authors: Research Institute of Scripps Clinic, Department of Immunology, La Jolla, CA 92037.
authors: L S
authors: LS
authors: Zalman
authors: M A
authors: MA
authors: Brothers
authors: H J
authors: HJ
authors: Müller-Eberhard
mesh_terms: D000818:Animals; D001798:Blood Proteins / Q000302:isolation & purification / Q000502:physiology / Q000652:urine*; D018957:CD59 Antigens; D002352:Carrier Proteins; D002645:Chickens; D015938:Complement Membrane Attack Complex; D003165:Complement System Proteins / Q000502:physiology; D004591:Electrophoresis, Polyacrylamide Gel; D004910:Erythrocyte Membrane / Q000276:immunology; D006023:Glycoproteins / Q000502:physiology; D006461:Hemolysis / Q000187:drug effects; D006801:Humans; D015151:Immunoblotting; D008565:Membrane Proteins / Q000302:isolation & purification; D019096:Vitronectin
chemical_list: D001798:Blood Proteins; D018957:CD59 Antigens; D002352:Carrier Proteins; D015938:Complement Membrane Attack Complex; D006023:Glycoproteins; D008565:Membrane Proteins; D019096:Vitronectin; C051590:CD59 protein, human; D003165:Complement System Proteins