Serum amyloid A (SAA) is a major acute-phase protein whose biochemical functions remain largely obscure. Human rheumatic synovial fluids were screened by high performance liquid chromatography mass spectrometry for SAA-derived peptides, specifically the sequence AGLPEKY (SAA98-104) which was previously shown to modulate various leukocyte functions. Two such fluids were found to contain a truncated version of SAA98-104. Synthetic SAA98-104 and several of its analogs were shown capable of binding isolated human CD4+ T-lymphocytes and stimulating them to produce interferon-γ. Given the high acute-phase serum level of SAA and its massive proteolysis by inflammatory related enzymes, SAA-derived peptides may be involved in host defense mechanisms. Copyright (C) 2000 Federation of European Biochemical Societies.
- Serum amyloid A