Complement System Functions

What is the result of inserting the 'membrane attack complex' into the cell membrane of target cells?

What role does C3b play in the immune response?

Which components are known as 'anaphylatoxins'?

Which complement component specifically activates and attracts neutrophils and macrophages?

Which pathway of complement activation bypasses C1, C4, and C2, starting directly with C3?

Which of the following is responsible for promoting the inflammatory reaction by causing mast cell degranulation?

Cell Lysis: The complement system can cause cell death by disrupting the cell membrane, allowing water and electrolytes to enter the cell, ultimately leading to cell lysis, often seen in bacterial cells, red blood cells, graft cells, or tumor cells.
Opsonization: Complement component C3b acts as an opsonin, enhancing phagocytosis of cells and antigen-antibody complexes.

Chemotaxis: C5a is a chemotactic agent, attracting neutrophils and macrophages to the site of inflammation.
Anaphylatoxins: C3a, C4a, and C5a are anaphylatoxins, causing degranulation of mast cells and releasing histamine and other inflammatory mediators, promoting the inflammatory reaction.

Classical Pathway: All components, starting with C1, are activated in this pathway.
Alternative Pathway: C1, C4, and C2 are bypassed, and C3 is activated directly in this pathway.
Lectin Pathway: All components, except C1, are activated in this pathway.