Synthetic Alzheimer amyloid beta/A4 peptides enhance production of complement C3 component by cultured microglial cells

Brain Res. 1993 Jan 22;601(1-2):88-94. doi: 10.1016/0006-8993(93)91698-r.


Primary microglial cultures prepared from newborn mice showed the production and release of the third component of complement (C3). Newly synthesized [35S]methionine-labelled C3 was purified by immunoprecipitation using anti-C3-antibody. C3 was detected by SDS-PAGE and fluoroaraphy of the immunoprecipitated protein from cell lysates as a 195 kDa band, and from the supernatants of cultures as two major bands corresponding to the C3 alpha-chain (125 kDa) and beta-chain (75 kDa), consistent with known C3 characteristics. Increased biosynthesis of C3 was elicited by endotoxin lipopolysaccharide (LPS). Further, the synthesis of C3 was increased 5-10-fold in response to various synthetic peptides corresponding to the amyloid beta/A4 protein, which is the main constituent of extracellular amyloid deposits in Alzheimer's disease (AD). The increased synthesis of C3 was shown to be dose dependent at concentrations of beta/A4 peptide ranging from 10 micrograms/ml to 50 micrograms/ml. These results suggest that complement components found previously in amyloid deposits may be partly derived from reactive microglia preferentially associated with senile plaques in AD brain.

MeSH terms

  • Amyloid beta-Peptides / pharmacology*
  • Animals
  • Astrocytes / drug effects
  • Astrocytes / metabolism
  • Cells, Cultured
  • Complement C3 / biosynthesis*
  • Electrophoresis, Polyacrylamide Gel
  • Fluorescent Antibody Technique
  • Granulocyte-Macrophage Colony-Stimulating Factor / pharmacology
  • Indicators and Reagents
  • Lipopolysaccharides / pharmacology
  • Macrophages / drug effects
  • Macrophages / metabolism
  • Mice
  • Mice, Inbred BALB C
  • Neuroglia / drug effects
  • Neuroglia / metabolism*
  • Parathyroid Hormone / pharmacology
  • Phagocytosis / drug effects
  • Precipitin Tests
  • Stimulation, Chemical


  • Amyloid beta-Peptides
  • Complement C3
  • Indicators and Reagents
  • Lipopolysaccharides
  • Parathyroid Hormone
  • Granulocyte-Macrophage Colony-Stimulating Factor