Activation of the Alternative (Properdin) Pathway by Divalent Cations

Abstract

Mg⁺⁺, Mn⁺⁺ and Co⁺⁺ activate the C system as judged by the reduction in cobra venom factor induced hemolysis, and cleavage of properdin factor B and C3. The maximum effect requires the addition of 5 to 10 mM of these cations to dialyzed sera. Guinea pig, human and rat sera respond in similar fashion indicating that these divalent cations can trigger the alternative pathway without the addition of other activating agents.