Candidate inhibitors of porcine complement

Ebbe B. Thorgersen, Yohannes T. Ghebremariam, Joshua M. Thurman, Michael Fung, Erik Waage Nielsen, V. Michael Holers, Girish J. Kotwal, Tom Eirik Mollnes

Research output: Contribution to journalArticlepeer-review

17 Scopus citations

Abstract

Therapeutic complement inhibition is a promising strategy for treatment of a number of diseases as judged from rodent studies. The species distance from rodents to humans may limit the clinical relevance of these studies. The pig is an alternative animal for studies of human diseases like sepsis and ischemia/reperfusion injury. However, available complement inhibitors for use in pigs are scarce. The aim of the present study was to investigate and compare the efficacy of selected candidate inhibitors of porcine complement in vitro for possible future application in vivo. Sera from three different pigs were each incubated with three different activators of the complement system (zymosan, heat-aggregated immunoglobulin G (HAIGG) and Escherichia coli). Three groups of complement inhibitor candidates were tested: serine protease inhibitors (FUT-175 and C1-inhibitor), monoclonal antibodies (anti-factor B (fB) and anti-factor D (fD)) and a recombinant regulatory protein (vaccinia virus complement control protein (VCP)). Read-out was the terminal C5b-9 complement complex (TCC). The serine protease inhibitors FUT-175 and C1-inhibitor dose-dependently inhibited TCC formation in zymosan-, HAIGG- and E. coli-activated porcine sera, but with different efficacy. Complete inhibition of TCC was obtained using 0.2 mg/mL FUT-175, but required 16 mg/mL of C1-inhibitor. The monoclonal anti-fB and -fD antibodies both inhibited TCC formation dose-dependently, but in different ways. Anti-fB at high dose (1 mg/mL) completely inhibited TCC formation in sera activated with zymosan and virtually completely in sera activated with HAIGG, but not in sera activated with E. coli. Anti-fD inhibited all three activators at low dose (0.05 mg/mL), and approximately 50% TCC reduction was obtained. The recombinant complement regulatory protein VCP efficiently and dose-dependently inhibited TCC formation with a complete inhibition found at 0.05 mg/mL for all three activators. All candidates tested inhibited porcine complement activation, but in different ways and to different degrees. Of the complement-specific candidates, VCP inhibited all activators completely at low doses.

Original languageEnglish (US)
Pages (from-to)1827-1834
Number of pages8
JournalMolecular Immunology
Volume44
Issue number8
DOIs
StatePublished - Mar 2007

Keywords

  • Anti-factor B
  • Anti-factor D
  • C1-inhibitor
  • Complement
  • Complement inhibitors
  • Escherichia coli
  • FUT-175
  • Porcine
  • Vaccinia virus complement control protein (VCP)

ASJC Scopus subject areas

  • Immunology
  • Molecular Biology

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