the dependence of antibody-and-complement-mediated lysis of virus-infected cells on the alternative pathway was examined utilizing the isolated cytolytic alternative pathway -- a system consisting of the six purified proteins of the alternative pathway of activation ( c3 , factors b and d , beta 1h , c3b inactivator and properdin ) , and the five proteins of the membrane attack pathway ( c5 -- 9 ) of complement .
C0033453
factors b
C0009498
complement