Immune System Gone Wrong: Part 2 Flashcards
Type II hypersensitivity
Cytotoxic hypersensitivity
What are the three pathways of Type II hypersensitivity?
- Activation of the complement system
- Antibody dependent cellular cytotoxicity
- Antibody-mediated cellular dysfunction
What antibodies mediates the activation of the complement system?
IgG or IgM
How is the complement system activated?
IgG or IgM antibodies bind to the antigen
What is Membrane Attack Complex?
Pokes holds and allows water influx into the red blood cell, causes lysis
What is hemolytic transfusion reactions and what do they involve?
- Type II hypersensitivity reaction
- Involves activation of complement system
When might hemolytic transfusion reactions occur?
Incompatible RBCs or incompatible plasma are transfused
What does hemolytic transfusion reactions lead to?
Intravascular hemolysis via MAC complex
What antibodies mediate antibody-dependent cellular cytotoxicity?
IgG or IgM
What do IgG or IgM antibodies bind during antibody-dependent cellular cytotoxicity?
Bind target cells and cytotoxic T cells or NK cells
During antibody-dependent cellular cytotoxicity, what do cytotoxic T cells and NK cells release? What does it cause?
- Performs and granzymes
- Apoptosis
Which of the three pathways of Type II hypersensitivity is non-cytotoxic?
Antibody-mediated cellular dysfunction
What two diseases are examples of antibody-mediated cellular dysfunction?
- Grave’s Disease
- Myasthenia Gravis
What happens during antibody-mediated cellular dysfunction?
Antibody binds to receptors and alters it’s activity
What antibodies are involved in Type III hypersensitivity?
IgG and IgM
What type of hypersensitivity is specifically in the vessel walls and/or tissues?
Type III
How does Type III hypersensitivity work?
When IgG or IgM bound antigens are in tissues, complement and neutrophils are activated
In Type III hypersensitivity, what do complements and neutrophils cause?
Inflammation, increased tissue permeability, tissue damage
Is Type III hypersensitivity local or systemic?
Can be both
Is local or systemic Type III hypersensitivity rare in humans?
Localized Type III
What is localized Type III hypersensitivity?
Damage is limited to area where immune complexes are first deposited
What is systemic Type III hypersensitivity?
Multiple sites in the body are damaged
What is serum sickness?
Immune system reacts to medicines that contain proteins to treat immune conditions, attacks it
What type of medication is specifically related to serum sickness?
Antivenoms
What hypersensitivity is serum sickness related to?
Type III
What is Type IV hypersensitivity mediated by?
- Helper T cells
- Cytotoxic T cells
When does Type IV hypersensitivity responses occur?
1-3 days after exposure