Chapter 17: Immunologic Disorder - Type II, III, IV Hypersensitivity Flashcards
What is type II hypersensitivity?
AB- dependent cytotoxicity
What occurs in type II hypersensitivity? (2)
- antibodies are produced against foreign human cells
- Activates macrophages and triggers complement to kill the cells
ex. blood transfusion
What is the ABO blood group system?
- antibodies target A and B antigens on RBC
What is an Rh factor?
another surface antigen on RBC
What is hemolytic disease of the newborn?
- when a child is produce between an Rh- female and Rh+ male
What happens in hemolytic disease of the newborn?
- Child has a 50% chance of being Rh+
- mother can make antibodies against Rh+ blood cells, which can attack blood cells of the second child
Hemolytic Disease of Newborn diagram
What is type III hypersensitivity? (2)
- immune complex formation
- occurs that certain antibody to antigen ratios in blood
What occurs in type III hypersensitivity?
- Ab forms small complexes with Ag and then gets trapped in membrane between cells
What can type III hypersensitivity result in? (3)
- can activate complement
- results in inflammation
- activate neutrophils to release enzymes that damages cells
What is type IV hypersensitivity? (3)
- delayed hypersensitivity
- cell-mediated response (T cells)
- not Ab mediated (i think only one out of all of them)
What occurs in type IV hypersensitivity? (2)
- causes a delayed reaction 24 to 72 hours after contact
- Time for Tc cells (cytotoxic t cells) to migrate to area
ex. contact dermatitis
How does type IV hypersensitivity happen? I think in terms of contact dermatitis
- small chemicals interact with skin proteins to form an antigen
- causes a change in skin cells
What is the cell mediated immune response in type IV hypersensitivity?
- Tc cells are activated to destroy the altered skin cells
- causes red, itchy, swelling skin
Explain why poison ivy is type 4 hypersensitivity? (2)
first contact - limited response, no dermatitis, memory T cells produced
Second Contact - memory T cells become activated by CTLS, causes allergic contact dermatitis