A novel method for direct measurement of complement convertases activity in human serum.

Research output: Contribution to journalArticle

Abstract

Complement convertases are enzymatic complexes that play a central role in sustaining and amplification of the complement cascade. Impairment of complement function directly or indirectly leads to pathologic conditions including higher infection rate, kidney diseases, autoimmune- or neurodegenerative diseases and ischemia-reperfusion injury. An assay for direct measurement of activity of the convertases in patient sera is not available. Existing assays testing convertase function are based on purified complement components and thus, convertase formation occurs under non-physiological conditions. We designed a new assay, in which C5 blocking compounds enabled separation of the complement cascade into two phases: the first ending at the stage of C5 convertases and the second ending with membrane attack complex formation. Use of rabbit erythrocytes or antibody-sensitized sheep erythrocytes as the platforms for convertase formation enabled easy readout based on measurement of hemolysis. Thus, properties of patient sera could be studied directly regarding convertase activity and membrane attack complex formation. Another advantage of this assay was the possibility to screen for host factors such as C3 nephritic factor and other anti-complement autoantibodies, or gain-of-function mutations, which prolong half-live of complement convertases. Herein, we present proof of concept, detailed description and validation of this novel assay.

Details

Authors
  • Anna Blom
  • Elena B Volokhina
  • Viktor Fransson
  • Patrik Strömberg
  • Lotta Berghard
  • Margareta Viktorelius
  • Tom Eirik Mollnes
  • Margarita Lopez-Holmberg
  • Lambertus P van den Heuvel
  • Tim H Goodship
  • Kevin J Marchbank
  • Marcin Okroj
Organisations
Research areas and keywords

Subject classification (UKÄ) – MANDATORY

  • Immunology in the medical area
Original languageEnglish
Pages (from-to)142-153
JournalClinical and Experimental Immunology
Volume178
Issue number1
Publication statusPublished - 2014
Publication categoryResearch
Peer-reviewedYes