Experimental confirmation of the C3 tickover hypothesis by studies with an Ab (S77) that inhibits tickover in whole serum

Abstract

The complement component 3 (C3) tickover hypothesis was put forward in the early 1970s to account for the spontaneous activation of the alternative complement pathway that occurs after the genetic absence or <i>in vitro</i> depletion of Factor I, the enzyme that is essential for the breakdown of C3b. The hypothesis was widely accepted, but experimental demonstration of the tickover was elusive. A phage Ab against C3b that inhibited the alternative complement pathway, but not the classical pathway, was described in 2009. Studies using this Ab in a variety of assays have now demonstrated that it acts primarily by inhibiting tickover, thereby confirming that tickover really exists.-Lachmann, P. J., Lay, E., Seilly, D. J. Experimental confirmation of the C3 tickover hypothesis by studies with an Ab (S77) that inhibits tickover in whole serum.