The novel acute phase protein, IHRP, inhibits actin polymerization and phagocytosis of polymorphonuclear cells

Objective and Design: In the present study, the involvement of the binding of 1HRP (inter-alpha-trypsin inhibitor family heavy chain-related protein) and actin in phagocyte activity was investigated. Materials and Methods: The actin polymerization and the phagocytic activity of the polymorphonuclear (PMN) cells were studied in the presence of 1HRP. Results: 1HRP inhibited the polymerization of actin and the phagocytic acti vity of the PMN cells. Conclusion: 1) 1HRP may bind to actin released from the damaged cells and s uppress its toxic action by preventing the formation of actin fibril. 2) 1H RP may bind to cell surface actin on PMN cells and inhibit their phagocytic activities. 3) From these results, 1HRP may act as an anti-inflammatory pr otein.