PROPERDIN - APPROACHING 4 DECADES OF RESEARCH

Properdin plays a key role in the alternative pathway by stabilizing t he C3 convertase. This review chronicles the evolution of our knowledg e of the structure and function of properdin over the 40 years since i ts discovery. The story begins with the first description of properdin and the controversy that ensued over its existence. Then, this review describes: the rediscovery and acceptance of properdin and the altern ative pathway as important components of natural immunity; properdin s tructure and molecular sequence; speculations on the significance of s equence similarities to thrombospondin and other proteins, and properd in biosynthesis. Finally, this review characterizes properdin deficien cy. Properdin does indeed appear to play an important role in homeosta sis.