C3 production of cultured human epidermal keratinocytes is enhanced by IFNgamma and TNFalpha through different pathways

J Invest Dermatol. 1997 Jan;108(1):62-7. doi: 10.1111/1523-1747.ep12285633.


We investigated the regulation of C3 production by human cultured epidermal keratinocytes by enzyme-linked immunosorbent assay. The results showed that IFNgamma and TNFalpha enhanced the synthesis of C3 by epidermal keratinocytes in a concentration-dependent manner. Moreover, a protein kinase C (PKC) inhibitor blocked C3 production, whereas PMA enhanced it. There was a synergistic effect between IFNgamma and TNFalpha. In experiments to investigate the role of protein tyrosine kinase (PTK) in C3 production, we found that treatment with herbimycin A, a specific inhibitor for the c-Src-related PTK, caused significant enhancement of the C3 production induced by IFNgamma or TNFalpha, suggesting that c-Src-type PTK(s) provides a negative signal to C3 production. Each competitive inhibitor of PTK, genistein or tyrphostin, substantially increased the C3 production by IFNgamma at lower concentrations, although each agent had little effect on TNFalpha-associated production of C3 at the same concentrations. The data show that pro-inflammatory cytokines IFNgamma and TNFalpha synergistically augment C3 production by epidermal keratinocytes by different pathways.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Cells, Cultured
  • Complement C3 / biosynthesis*
  • Complement C3 / physiology
  • Drug Synergism
  • Enzyme Activation / drug effects
  • Humans
  • Infant, Newborn
  • Interferon-gamma / pharmacology*
  • Keratinocytes / cytology*
  • Keratinocytes / metabolism*
  • Male
  • Protein Kinase C / metabolism
  • Protein-Tyrosine Kinases / metabolism
  • Signal Transduction / drug effects
  • Tumor Necrosis Factor-alpha / pharmacology*


  • Complement C3
  • Tumor Necrosis Factor-alpha
  • Interferon-gamma
  • Protein-Tyrosine Kinases
  • Protein Kinase C