Chapter 17: Immunologic Disorder - Type II, III, IV Hypersensitivity

Question 1

What is type II hypersensitivity?

Answer 1

AB- dependent cytotoxicity

Question 2

What occurs in type II hypersensitivity? (2)

Answer 2

• antibodies are produced against foreign human cells
• Activates macrophages and triggers complement to kill the cells
  ex. blood transfusion

Question 3

What is the ABO blood group system?

Answer 3

• antibodies target A and B antigens on RBC

Question 4

What is an Rh factor?

Answer 4

another surface antigen on RBC

Question 5

What is hemolytic disease of the newborn?

Answer 5

• when a child is produce between an Rh- female and Rh+ male

Question 6

What happens in hemolytic disease of the newborn?

Answer 6

• 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

Question 7

Hemolytic Disease of Newborn diagram

Answer 7

Question 8

What is type III hypersensitivity? (2)

Answer 8

• immune complex formation
• occurs that certain antibody to antigen ratios in blood

Question 9

What occurs in type III hypersensitivity?

Answer 9

• Ab forms small complexes with Ag and then gets trapped in membrane between cells

Question 10

What can type III hypersensitivity result in? (3)

Answer 10

• can activate complement
• results in inflammation
• activate neutrophils to release enzymes that damages cells

Question 11

What is type IV hypersensitivity? (3)

Answer 11

• delayed hypersensitivity
• cell-mediated response (T cells)
• not Ab mediated (i think only one out of all of them)

Question 12

What occurs in type IV hypersensitivity? (2)

Answer 12

• causes a delayed reaction 24 to 72 hours after contact
• Time for Tc cells (cytotoxic t cells) to migrate to area
  ex. contact dermatitis

Question 13

How does type IV hypersensitivity happen? I think in terms of contact dermatitis

Answer 13

• small chemicals interact with skin proteins to form an antigen
• causes a change in skin cells

Question 14

What is the cell mediated immune response in type IV hypersensitivity?

Answer 14

• Tc cells are activated to destroy the altered skin cells
• causes red, itchy, swelling skin

Question 15

Explain why poison ivy is type 4 hypersensitivity? (2)

Answer 15

first contact - limited response, no dermatitis, memory T cells produced
Second Contact - memory T cells become activated by CTLS, causes allergic contact dermatitis