 This is thought to be the result of Factor H having the ability to adopt conformations with lower or higher activities as a cofactor for C3 cleavage or decay accelerating activity.The lower activity conformation is the predominant form in solution and is sufficient to control fluid phase amplification.The more active conformation is thought to be induced when Factor H binds to glycosaminoglycans (GAGs) and or sialic acids that are generally present on host cells but not, normally, on pathogen surfaces ensuring that self surfaces are protected whilst complement proceeds unabated on foreign surfaces.