Chapter 8: Effector mechanisms of humoral immunity Flashcards
What does the complement system plus antibodies lead to?
- lysis of microbes
- phagocytosis of microbes
- inflammation
How do antibodies protect the epithelial barrier?
antibodies block penetration of microbe through epithelial barrier
How do antibodies protect cells from infection by microbe?
antibodies block binding of microbe and infection of cells
How do antibodies protect the cells from toxins?
antibodies block binding of toxin to cellular receptors
What is the process of antibody-mediated opsonization and phagocytosis of microbes?
- opsonization of microbe by IgG
- binding of opsonized microbe to Fc receptors on phagocyte
- Fc receptor signals to activate phagocyte
- phagocytosis and killing of ingested microbe
What antibody binds antibody coated cell and to low-affinity CD16 on natural killer cell to allow for killing of first cell?
IgG
What antibody acts as a bridge between eosinophil (FceRI) and helminth to result in helminth death?
IgE
What cytokine signals between Th2 cell and eosinonphil to activate it?
IL-5
IgE- and eosinophil-mediated killing of…
helminths
What protein recognizes an antigen-engaged antibodies to turn on the classical pathway?
complement C1 protein
What are the steps of the classical pathway of the complement system?
- complement C1 protein engages with antigen-engaged antibody
- C3a causes inflammation
- C3b causes opsonization and phagocytosis
- C5a causes inflammation
- C6-9 causes lysis of microbe via the membrane attack comples (MAC)
What antibody is important for mucosal immunity (including the mouth)?
IgA
What do C6-9 cause in the complement system?
lysis of microbe via MAC (membrane attack complex)
What does C5a and C3a do in the complement system?
inflammation
What does C3b do in the complement system?
opsonization and phagocytosis
