The classical and<unk> s.<unk>  pathway. (Some labels are in Polish.) The<unk>  pathway is a type of cascade reaction of the complement system and is a component of the innate immune system, a natural defense against infections. The<unk>  pathway is one of three complement pathways that opsonize and kill pathogens. The pathway is triggered when the C3b protein directly binds a microbe. It can also be triggered by foreign materials and damaged tissues.
Alternative complement pathway
Lectin pathway
Duffy antigen system
Fc receptor
Complement receptor 1
Fragment antigen-binding
Complement component 3
Complement component 4