Membrane complement regulatory proteins: insight from animal studies and relevance to human diseases

The complement system plays an important role in host defense. However, if not properly regulated, activated complement can also cause significant dam age to host tissues. To prevent complement-mediated autologous tissue damag e, host cells express a number of membrane-bound complement regulatory prot eins. These include decay-accelerating factor (DAF, CD55), membrane cofacto r protein (MCP, CD46) and CD59. Recent studies of membrane complement regul atory proteins from various animal species have revealed similarities as we ll as significant differences from the corresponding human proteins. In thi s review, we summarize recent advances in this area and contrast the struct ure, function and tissue distribution of membrane complement regulatory pro teins in human and nonprimate mammalian species. We also discuss how the ch aracterization of the animal proteins has provided important clues and migh t continue to show relevance to the pathogenesis and therapeutics of a numb er of human diseases. (C) 2001 Elsevier Science B,V. AH rights reserved.