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Synthesis of factor D by normal human hepatocytes
1Department of Medical Technology, Osaka Prefectural College of Health Sciences, Osaka, Japan.
International Archives of Allergy and Immunology
|September 6, 2000
Summary
Normal human hepatocytes constitutively synthesize complement factor D, challenging the long-held belief that only adipose tissue produces this protein. This finding suggests the liver may be a significant source of plasma factor D.
Area of Science:
- Biochemistry
- Immunology
- Hepatology
Background:
- Complement factor D is traditionally attributed to adipose tissue synthesis.
- Its exclusive production by adipose tissue has been a prevailing hypothesis.
Purpose of the Study:
- To investigate the synthesis of complement factor D by hepatocytes.
- To determine if the liver contributes to plasma factor D levels.
Main Methods:
- Primary culture of normal human hepatocytes.
- Quantification of factor D in culture supernatants using ELISA.
- Analysis of secreted factor D by Western blotting and immunoblotting.
Main Results:
- Factor D was detected in hepatocyte culture supernatants, indicating synthesis.
- Secretion was constitutive and not significantly affected by TNF-alpha, IFN-gamma, IL-1beta, or LPS.
- Cycloheximide reversibly inhibited factor D secretion.
- Immunoblot analysis revealed double bands for secreted factor D.
Conclusions:
- Normal human hepatocytes possess the capability to synthesize factor D.
- The liver is potentially a major contributor to circulating factor D levels.