Answer:
TLR binding to PAMP on the microbe
Explanation:
The complement system is a group of proteins in the blood that enhance immune responses by complementing the ability of antibodies and phagocytic cells to mediate effector responses (e.g., lysis, activation of inflammation, opsonization, solubilization of immune complexes, etc). Complement can be activated through the recognition of microbes by soluble pattern-recognition molecules (i.e., lectin pathway) or antibodies (i.e., classical pathway). The classical pathway requires the formation of antigen-antibody complexes for its activation (it is a specific immune response). On the other hand, Toll-like Receptors (TLRs) are molecular receptors that recognize viral and bacterial products (i.e., pathogen-associated molecular patterns or PAMPs), which is a key defense mechanism from the innate immune system response.
