Activation of the early components of the classical complement pathway under physiologic conditions.
D001665:Binding Sites; D001769:Blood; D003167:Complement Activation; D003172:Complement C1 / Q000378:metabolism / Q000502:physiology*; D003175:Complement C2 / Q000502:physiology; D003181:Complement C4 / Q000502:physiology; D003171:Complement Pathway, Classical; D006801:Humans; D007700:Kinetics; D013997:Time Factors
D003172:Complement C1; D003175:Complement C2; D003181:Complement C4