Techniques of Fractionating Complement in-Vivo by the Use of Activated Complement Components to Trigger the C3b Feedback Cycle

Cobra venom factor is a highly effective complement-activating agent in vivo by virtue of its ability to trigger the C3b feedback cycle. An investigation has been made to see whether triggering of the C3b feedback cycle by activated autologous complement components could similarly provide a mechanism for in vivo complement activation.

It has been found that C4^oxy2 added to serum triggers the C3b feedback cycle, effectively in vitro. Similar C3b, Bb can be used as the triggering enzyme.

Experiments have been performed in vivo in rats showing that significant complement activation accompanied by the leukocyte changes characteristic of CVF treatment can be produced with the altered complement components. Such techniques promise to be applicable to complement (in)activation in vivo in man.