Immunology Lec 6

Question 1

Lecture 6:
What is the mechanism of Type I Hypersensitivity (Allergy or Atopy)?

Answer 1

Mediated by IgE antibodies; upon exposure to an allergen, IgE binds to mast cells causing degranulation and release of histamine and other mediators.

Question 2

Give examples of conditions caused by Type I Hypersensitivity.

Answer 2

Allergic rhinitis, asthma, anaphylaxis.

Question 3

What are the symptoms of Type I Hypersensitivity?

Answer 3

Immediate reaction, vasodilation, smooth muscle contraction, and increased vascular permeability leading to edema.

Question 4

Describe the mechanism of Type II Hypersensitivity (Antibody-Mediated).

Answer 4

Mediated by IgM and IgG antibodies that bind to cell surface antigens leading to cell destruction, inflammation, and cellular dysfunction.

Question 5

Provide examples of conditions associated with Type II Hypersensitivity.

Answer 5

Hemolytic disease of the newborn (Rh incompatibility), transfusion reactions.

Question 6

What are the symptoms of Type II Hypersensitivity?

Answer 6

Symptoms depend on the specific cells or tissues targeted, often involving destruction of red blood cells or other cellular components.

Question 7

Explain the mechanism of Type III Hypersensitivity (Immune Complex-Mediated).

Answer 7

Formation of immune complexes (antigen-antibody) that deposit in tissues and cause inflammation and tissue damage.

Question 8

Give examples of diseases caused by Type III Hypersensitivity.

Answer 8

Systemic lupus erythematosus, rheumatoid arthritis, Arthus reaction.

Question 9

What are the symptoms of Type III Hypersensitivity?

Answer 9

Localized inflammation, thrombosis, and tissue necrosis.

Question 10

Describe the mechanism of Type IV Hypersensitivity (Delayed-Type T-Cell Mediated).

Answer 10

Mediated by T cells rather than antibodies, involving the release of cytokines that recruit and activate macrophages and other immune cells.

Question 11

Provide examples of conditions associated with Type IV Hypersensitivity.

Answer 11

Contact dermatitis (e.g., poison ivy), tuberculosis, chronic transplant rejection.

Question 12

What are the symptoms of Type IV Hypersensitivity?

Answer 12

Delayed reaction (24-48 hours), local tissue damage, and inflammation.

Question 13

What are the pathological consequences of Type I, Hypersensitivity?

Answer 13

Rapid onset with symptoms like swelling, itching, and anaphylaxis in severe cases.

Question 14

What are the pathological consequences of Type II Hypersensitivity?

Answer 14

Destruction of target cells leading to conditions like hemolytic anemia or organ-specific autoimmune diseases.

Question 15

What are the pathological consequences of Type III Hypersensitivity?

Answer 15

Immune complexes deposit in tissues causing inflammation and damage, as seen in diseases like lupus.

Question 16

What are the pathological consequences of Type IV Hypersensitivity?

Answer 16

Delayed reaction causing chronic inflammation and granuloma formation, significant in infections like tuberculosis.

Question 17

How is Type I Hypersensitivity regulated?

Answer 17

Involves identifying allergens and using treatments like antihistamines, mast cell stabilizers, and desensitization therapy.

Question 18

How is Type II Hypersensitivity regulated?

Answer 18

Requires careful blood matching and use of medications like corticosteroids to reduce immune response.

Question 19

How is Type III Hypersensitivity regulated?

Answer 19

Involves managing underlying autoimmune conditions and using immunosuppressive drugs.

Question 20

How is Type IV Hypersensitivity regulated?

Answer 20

Involves avoiding known contact allergens and using anti-inflammatory drugs to control reactions.