Final answer:
Only antibodies of type IgG or IgM can activate the C1 component in complement system leading to the cleavage of C2 and C4, ultimately aiding in pathogen elimination.
Step-by-step explanation:
The student's question pertains to the activation of the complement system, specifically the initiation of the classical pathway by the binding of the complement component C1 to antibody-antigen (Ab-Ag) complexes. Only antibody molecules of the types IgG or IgM are capable of binding to antigen and subsequently activating C1, which leads to the cleavage of the complement components C2 and C4 and further progression of the complement cascade. This can result in cell lysis, enhanced phagocytosis, or the formation of a membrane-attack complex (MAC) against the invading pathogen. The specificity between an antibody and its corresponding antigen is fundamental to the adaptive immune response.