Immunology

Question 1

What type of hypersensitivity is IMHA?

What antibody is the pain player in each intravascular and extravascular hemolysis?

Answer 1

Type III hypersensitivity

Intravascular: IgM (or IgG)
Extravascular: IgG

Question 2

How neurtophils kill bacteria via oxidative burst? (explain the cascade/steps)

Answer 2

1. Bacteria are phagocytized
2. with NADPH & O2, superoxide anion is formed
3. Hydrogen peroxide
4. Hypochloric acid
5. Kill bacteria
6. Lysozymes & defense’s acid hydrolase digests bacteria after their death

Question 3

Th2 stimulated by ___, ___

Answer 3

IL-4, IL-1

Question 4

Th1 stimulated by ___, ___

Answer 4

IL-12, IL-2

Question 5

Ig which does cross placenta

Answer 5

IgG crosses placenta

IgA does NOT cross placenta, does NOT activated complement
(IgA is a dimer, IgM is a pentamer, IgG is a monomer)

Question 6

What is the APC cells in the skin?

Answer 6

Langerhans cells

Question 7

Pemphigus folliaceous

1. Common skin lesion affected
2. What is the target of antibodies

Answer 7

1. Face (not mucosal; only epidermal desmosomes are affected)
2. Desmoglein 1

Question 8

What factor inhibits complement C3b?

Answer 8

Factor I

Question 9

What is the mediators involved and examples in type I hypersensitivity?

Answer 9

Type I: Allergy, immediate
Examples: anaphylaxis, asthma, atopy, vaccine reaction
Mediators: IgE, Th2 type cytokines, histamine, leukotrienes, PGs, PAR

Question 10

What is the mediators involved and mediators in type II hypersensitivity?

Answer 10

Type II: cytotoxic, antibody-dependent
Examples: IMHA, ITP, pemphigus, transfusion reaction
Mediators: IgG, IgM

Question 11

What is the mediators involved and mediators in type III hypersensitivity?

Answer 11

Type III: immune complex disease, Ab-Ag complexes deposited
Examples: SLE, Lyme nephritis, rheumatoid arthritis
Mediators: aggregation of antigens, IgG, IgM, complement proteins

Question 12

What is the mediators involved and mediators in type IV hypersensitivity?

Answer 12

Type IV: delayed reaction, delayed hypersensitivity, cell-mediated, antibody independent
Examples: contact dermatitis, tuberculosis, chronic transplant rejection
Mediators: T cells, monocytes, macrophages

Question 13

Defensins

Answer 13

Alpha granules of neutrophils

Cause collapse of cholesterol free bacterial cell membranes

Question 14

What is a necessary step in intravascular hemolysis?

Answer 14

Complement activation by classical pathway (antigen-antibody complexes)

Question 15

Which receptor on the cell surface recognizes LPS?

Answer 15

TLR4

Question 16

What type of vaccine that causes Th1 responses?

Answer 16

Live, modified lice, viral and DNA vaccines

Vaccines that stimulate cell-mediated immunity

Question 17

Eosinophilic bronchopneumopathy (EBP) is characterized by eosinophilic infiltration and is dominated by CD4+ T cells. What type of immune response is involved in EBP?

Answer 17

Th2 response

Question 18

What is the most potent inducer/activator of tumor cell destruction by NK cells and cytotoxic T cells?

Answer 18

IL-12 (very important in induction of Th1 cell-mediated immunity)

Question 19

Anti-inflammatory cytokines

Answer 19

IL-10, IL-4

Both are humoral immunity

Question 20

Pyrogens

Answer 20

IL-1, IL-6, IL-8, TNF-alpha, IFN-gamma

Question 21

Target of MHC I and II

Answer 21

MHC I - intracellular pathogens (e.g. virus)

MHC II - extracellular pathogens (e.g. bacteria)