Complement Stimulates Retinal Pigment Epithelial Cells to Undergo Pro-Inflammatory Changes

Ophthalmic Res. 2015;54(4):195-203. doi: 10.1159/000439596. Epub 2015 Oct 27.


Background/aims: We examined the effect of human complement sera (HCS) on retinal pigment epithelial (RPE) cells with respect to pro-inflammatory mediators relevant in early age-related macular degeneration (AMD).

Methods: RPE cells were treated with complement-containing HCS or with heat-inactivated (HI) HCS or C7-deficient HCS as controls. Cells were analysed for C5b-9 using immunocytochemistry and flow cytometry. Interleukin (IL)-6, IL-8, and monocyte chemoattractant protein-1 (MCP-1) were quantified by ELISA and RT-PCR. Tumour necrosis factor-α (TNF-α), intercellular adhesion molecule-1 (ICAM-1) and vascular cell adhesion molecule-1 (VCAM-1), were analysed by Western blotting. The intracellular distribution of nuclear factor (NF)-x03BA;B was investigated by immunofluorescence.

Results: A concentration-dependent increased staining for C5b-9 but no influence on cell viability was observed after HCS treatment. ELISA and RT-PCR analysis revealed elevated secretion and expression of IL-6, IL-8, and MCP-1. Western blot analysis showed a concentration-dependent increase in ICAM-1, VCAM-1, and TNF-α in response to HCS, and immunofluorescence staining revealed nuclear translocation of NF-x03BA;B.

Conclusion: This study suggests that complement stimulates NF-x03BA;B activation in RPE cells that might further create a pro-inflammatory environment. All these factors together may support early AMD development.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Blotting, Western
  • Cells, Cultured
  • Complement Membrane Attack Complex / metabolism*
  • Complement System Proteins / physiology*
  • Cytokines / metabolism
  • Enzyme-Linked Immunosorbent Assay
  • Flow Cytometry
  • Humans
  • Immunohistochemistry
  • Inflammation Mediators / metabolism*
  • Intercellular Adhesion Molecule-1 / metabolism
  • Macular Degeneration / metabolism
  • NF-kappa B / metabolism*
  • Real-Time Polymerase Chain Reaction
  • Retinal Pigment Epithelium / metabolism*
  • Vascular Cell Adhesion Molecule-1 / metabolism


  • Complement Membrane Attack Complex
  • Cytokines
  • Inflammation Mediators
  • NF-kappa B
  • Vascular Cell Adhesion Molecule-1
  • Intercellular Adhesion Molecule-1
  • Complement System Proteins