<prompt> Complement binding immunoglobulin the classical pathway is -IgG IgMIgG IgAIgG IgDIgD IgE  <response>: IgM is paicularly effective at complement activation by binding to C1. IgG activates the classical pathway of the complement system, a cascade of immune protein production Ref: Ananthanarayan Parkers textbook of microbiology 9th edition pf:98 