Immunology 7 8 - PRR, TLR, Hypersensitivity

Question 1

Examples of motifs that TLRs recognize

Answer 1

LPS, dsRNA, cell-wall components, flagellin, CpG (humans don’t have many sequences where C comes before G, thus it is an indicator for bacteria)

Question 2

Passive vs active vaccine

Answer 2

Passive: receive preformed ABs. mother to child (placenta or milk); deliberate AB transfer (monoclonal AB). Active: induce a response. normal infection, Controlled infection (wild-type, live attenuated, recombinant), Artificial selection (inactivated, purified components, etc.) Normal and controlled is best.

Question 3

Whole cell vaccine

Answer 3

Inactivated or attenuated. Ex. cholera, pertussis, TB, plague.

Question 4

Capsular polysaccharide vaccine

Answer 4

Meningitis, pneumococcal pneumonia, H influenzae B.

Question 5

Toxoid vaccines

Answer 5

Inactivated toxin. Diphtheria, Tetanus.

Question 6

Whole viral particle vaccines

Answer 6

Inactivated/attenuated. Influenza, MMR, Polio, rabies, yellow fever.

Question 7

Viral antigens

Answer 7

Hep B.

Question 8

DNA vaccine

Answer 8

Clone viral gene in a plasmid. Inject into muscle (will get transcribed in cell). Should confer resistance.

Question 9

Subcomponent vaccines.

Answer 9

1. Protein with B and T cell epitopes. 2. Non protein: B cell only. 3. B cell epitopes joined to protein (B and T cell). 4. Minimal: 2 peptides, one for B and one for T.

Question 10

Live attenuated vs inactivated

Answer 10

Attenuated: only one booster, humoral and cell-meditated response, but less stable and can revert. Inactive: more stable, cannot revert, but more boosters

Question 11

Definition of hypersensitivity

Answer 11

Normal mechanisms of immune function sometimes damage host. If the damage outweighs the benefit, this is hypersensitivity

Question 12

Type 1: IgE-mediated hypersensitivity

Answer 12

2-30 min. Ag induces cross-linkage of IgE bound to mast cells and basophils. 2nd exposure releases vasoactive mediators, causes smooth muscle contraction, permeability, vasodilation.

Question 13

Type 1: signs

Answer 13

Systemic anaphylaxis; Localized anaphylaxis: Hay fever, Asthma, Hives, Food allergies, Eczema

Question 14

Type 1: mediators and Tx.

Answer 14

Histamine, leukotrienes, bradykinin, prostaglandins, cytokines. Treat with epinephrine, antihistamines

Question 15

Type 2: Antibody-mediated cytotoxic hypersensitivity

Answer 15

5-8 h. Ab directed against cell-surface antigens mediates cell destruction via complement activation or ADCC (neutrophils and macrophages can also get recruited).

Question 16

Type 2: signs

Answer 16

Blood-transfusion reactions, Erythroblastosis fetalis, Autoimmune hemolytic anemia

Question 17

Type 2: example of Rh

Answer 17

Rh+ baby in Rh- mother. At birth some blood mixes. Mother develops IgGs against it. Second pregnancy, some RBC fragment may cross so it triggers B cells, IgG’s can cross placenta and cause erythroblastsis fetalis. Preventable with drugs.

Question 18

Type 3: Immune complex- mediated hypersensitivity

Answer 18

2-8 h. Ag-Ab complexes deposited in various tissues (glomeruli, blood vessels) induce complement activation and an ensuing inflammatory response. Similar to Type 2, but you can see visible lump of Ag-Ab complexes plus cells etc.

Question 19

Type 3: signs etc.

Answer 19

Localized Arthus reaction (in skin), Generalized reactions: Serum sickness, Glomerulonephritis, Rheumatoid arthritis, Systemic lupus erythematosus

Question 20

Type 4: Cell-mediated hypersensitivity

DTH

Answer 20

24-72 h Sensitized TDTH cells release cytokines that activate macrophages or TC cells, which mediate direct cellular damage.

Question 21

Type 4: signs and example causes

Answer 21

Signs: Contact dermatitis, Tubercular lesions, Graft rejection. Causes: TB, Listeria, herpes, measles, poison ivy

Question 22

Penicillin hypersensitivity reactions

Answer 22

Type 1: IgE, Urticaria, systemic anaphylaxis. Type 2: IgM, IgG, hemolytic anemia. Type 3: IgG, Serum sickness, glomerulonephritis. Type 4: T dth cells, contact dermititis