title: Native polymeric forms of properdin selectively bind to targets and promote activation of the alternative pathway of complement.
abstract: Properdin, a positive regulator of the complement system, has recently been reported to bind to certain pathogenic microorganisms, to early or late apoptotic and necrotic cells, and to particular live human cell lines, thus providing a platform for de novo convertase assembly and complement activation. These studies, with some contradictory results, have been carried out with purified properdin, which forms a series of oligomers of a ∼53,000 Mr subunit, assembling into dimers (P₂), trimers (P₃), tetramers (P₄) and higher forms (P(n)). The P(n) forms have been shown to likely be an artefact of purification that results from procedures including freeze-thawing of properdin. In this study we isolated the individual natural forms of properdin (P₂, P₃, and P₄) and separated them from the P(n) forms present in purified frozen properdin using ion exchange and/or size exclusion chromatography. We analyzed the ability of each form to bind to live or necrotic Jurkat and Raji cells, rabbit erythrocytes (E(R)), and zymosan by FACS analysis. While the unseparated properdin and the purified P(n) forms bound to all the surfaces except E(R), the physiological P₂-P₄ forms specifically bound only to zymosan and to necrotic nucleated cells. Our results indicate that aggregated P(n) present in unseparated properdin may bind non-specifically to some surfaces and should be separated before analysis in order to obtain meaningful results. Finally, we have determined for the first time that the physiological forms of human properdin can selectively recognize surfaces and enhance or promote complement activation, which is in agreement with the reported role for properdin as a complement initiator.
authors.affiliation: Department of Medical Microbiology and Immunology, College of Medicine, University of Toledo, Toledo, OH 43614, USA. viviana.ferreira@utoledo.edu
authors.forename: Viviana P
authors.initials: VP
authors.lastname: Ferreira
authors.forename: Claudio
authors.initials: C
authors.lastname: Cortes
authors.forename: Michael K
authors.initials: MK
authors.lastname: Pangburn
mesh_terms: D000818:Animals; D045744:Cell Line, Tumor; D003170:Complement Pathway, Alternative; D004912:Erythrocytes / Q000276:immunology; D006801:Humans; D019169:Jurkat Cells; D011414:Properdin / Q000276:immunology* / Q000302:isolation & purification; D055503:Protein Multimerization; D011817:Rabbits; D015054:Zymosan / Q000276:immunology
chemical_list: D011414:Properdin; D015054:Zymosan
references.citation: Cell Mol Biol (Noisy-le-grand). 2004 Mar;50(2):107-16
references.pmid: 15095782
references.citation: Annu Rev Immunol. 2010;28:131-55
references.pmid: 19947883
references.citation: J Exp Med. 1975 Oct 1;142(4):856-63
references.pmid: 1185108
references.citation: Science. 1954 Aug 20;120(3112):279-85
references.pmid: 13186838
references.citation: J Exp Med. 2000 Aug 7;192(3):359-66
references.pmid: 10934224
references.citation: Clin Exp Immunol. 1982 Nov;50(2):291-7
references.pmid: 7151327
references.citation: Genomics. 1995 Sep 1;29(1):1-8
references.pmid: 8530058
references.citation: J Immunol. 1989 Feb 1;142(3):842-7
references.pmid: 2913153
references.citation: J Immunol Methods. 1987 Aug 24;102(1):7-14
references.pmid: 3624878
references.citation: Am J Physiol Renal Physiol. 2008 Nov;295(5):F1397-403
references.pmid: 18753294
references.citation: J Biol Chem. 1981 Apr 25;256(8):3995-4006
references.pmid: 6783652
references.citation: J Biol Chem. 1984 Apr 10;259(7):4582-8
references.pmid: 6707020
references.citation: J Immunol. 1989 Jan 1;142(1):202-7
references.pmid: 2909614
references.citation: Biochem Soc Trans. 1990 Dec;18(6):1161-2
references.pmid: 2088833
references.citation: Proc Natl Acad Sci U S A. 1976 Feb;73(2):612-6
references.pmid: 54923
references.citation: J Immunol. 2008 Mar 1;180(5):3313-8
references.pmid: 18292556
references.citation: J Biol Chem. 2006 Jan 27;281(4):2128-32
references.pmid: 16301317
references.citation: Mol Immunol. 1988 Dec;25(12):1363-70
references.pmid: 3237219
references.citation: J Immunol. 1996 Oct 15;157(8):3666-71
references.pmid: 8871668
references.citation: Eur J Biochem. 1994 Feb 1;219(3):759-64
references.pmid: 8112326
references.citation: Springer Semin Immunopathol. 1984;7(2-3):163-92
references.pmid: 6238433
references.citation: Trends Immunol. 2009 Jan;30(1):43-51
references.pmid: 19058756
references.citation: J Immunol. 1993 Sep 1;151(5):2521-8
references.pmid: 8360474
references.citation: J Immunol. 2010 Jul 1;185(1):507-16
references.pmid: 20530262
references.citation: Scand J Infect Dis. 1983;15(4):339-45
references.pmid: 6658381
references.citation: Blood. 2008 Jan 15;111(2):732-40
references.pmid: 17916747
references.citation: Proc Natl Acad Sci U S A. 2008 Jul 1;105(26):9023-8
references.pmid: 18579773
references.citation: J Immunol. 2018 Jul 1;201(1):7-10
references.pmid: 29914936
references.citation: J Immunol. 2007 Aug 15;179(4):2600-8
references.pmid: 17675523
references.citation: Biochem J. 1987 Apr 15;243(2):507-17
references.pmid: 3307764
references.citation: Mol Immunol. 2003 Jan;39(11):669-75
references.pmid: 12493642
references.citation: J Immunol. 2008 Jun 1;180(11):7613-21
references.pmid: 18490764
references.citation: Platelets. 2008 Aug;19(5):359-64
references.pmid: 18791942
references.citation: Immunol Today. 1999 Jan;20(1):17-21
references.pmid: 10081225
references.citation: Mol Immunol. 1999 Sep-Oct;36(13-14):837-42
references.pmid: 10698337
references.citation: J Exp Med. 1980 Mar 1;151(3):501-16
references.pmid: 6444659
references.citation: Mol Immunol. 1999 Sep-Oct;36(13-14):863-7
references.pmid: 10698340
references.citation: J Immunol. 1997 May 1;158(9):4444-51
references.pmid: 9127010
references.citation: Methods Enzymol. 1993;223:35-46
references.pmid: 8271963
references.citation: Clin Immunol. 2009 Jun;131(3):456-62
references.pmid: 19328743
references.citation: Rheumatology (Oxford). 2005 Sep;44(9):1101-7
references.pmid: 15928001
references.citation: J Exp Med. 1975 Sep 1;142(3):760-72
references.pmid: 1165475
references.citation: Mol Immunol. 2008 Mar;45(5):1199-207
references.pmid: 17961651
references.citation: Nature. 1988 Sep 1;335(6185):82-5
references.pmid: 3045564
references.citation: Biochemistry. 1991 Aug 13;30(32):8000-8
references.pmid: 1868073
references.citation: Immunobiology. 2007;212(4-5):363-70
references.pmid: 17544821