Type IV Hypersensitivity- Lecture 10/28/21

Question 1

Delayed hypersensitivity

Answer 1

The mechanisms are the same as cell-mediated immunity, but results in tissue damage

Question 2

Subsets of CD4+ T cells important for Type IV

Answer 2

Th1 (especially when activating CD8+ cells) and Th-17

Question 3

2 stages of type IV hypersensitivity

Answer 3

• Sensitization stage (have not seen ag before)

- Elicitation stage (response stage)

Question 4

Examples of contact dermatitis (5)

Answer 4

• Poison Ivy
• Cosmetics
• Chemicals
• Latex
• Metals (Ni, Zn)

Question 5

Length of time before infection

Answer 5

3-5 days

Question 6

Patch test

Answer 6

Tests for hypersensitivity that keeps at there for several days 9taped on)

Question 7

Tb skin test

Answer 7

Inject purified protein derivative into the skin and evaluate 3 days later for response

Question 8

Examples of Type IV hypersensitivity may cause tissue damage in autoimmunity and chronic inflammation (6)

Answer 8

• IDDM
• Rheumatoid arthritis
• Multiple sclerosis
• Crohn’s disease (ag from gut microbiota)
• Psoriasis
• Celiac disease (antigen from wheat, barley)

Question 9

Treatment for rheumatoid arthritis

Answer 9

ANti-TNF therapy

Question 10

Psoriasis

Answer 10

Present on skin, can lead to psoriatic arthritis

Question 11

Multiple sclerosis

Answer 11

Cytotoxic killing of oligodendrocytes- damage to the myelin leads to slowed signaling (range of migrating symptoms)

Question 12

Celiac disease

Answer 12

Transglutaminase modifies the peptides so they can bind MHC class II molecules, signal CD4 T cells activate D8 cells which kill epithelia