Misc

Question 1

Positive selection of immature T cells

Answer 1

Thymic cortex. CD4+/CD8+ T cells selecting for those capable of binding to self-MHC molecules.

Question 2

Negative selection of immature T cells

Answer 2

Thymic medulla. CD4+ or CD8+ T cells selecting for those NOT strongly activated by self-MHC/AIRE molecules.

Question 3

3 cell types that are APCs

Answer 3

Macrophages, B cells, dendritic cells

Question 4

Types of helper T cells & characteristic cytokines

Answer 4

Th1 - IFNg
Th2 - IL-4
Th17 - IL-17
Treg - IL-10

Question 5

IgG

Answer 5

Secondary response to antigen after class-switching. Activates complement. Most abundant in serum. Crosses placenta.

Question 6

IgA

Answer 6

Does NOT do complement. Secreted in mucus membrane. Most abundant production (but secreted).

Question 7

IgM

Answer 7

Immediate response to antigen. Activates complement. Monomer on B cell surface, but pentamer if secreted

Question 8

IgD

Answer 8

On surface of B cell

Question 9

IgE

Answer 9

Activates mast cell & basophils. Type 1 hypersensitivity. Confers immunity to worms by activating eosinophils.

Question 10

ESR vs CRP

Answer 10

ESR is elevated longer, marker of chronic inflam (SLE). CRP rises within hours & made from liver.

Question 11

Hot T-Bone Steak (IL-1 to IL-6 function)

Answer 11

IL-1 - fever
IL-2 - stimulates T cells
IL-3 - stimulates bone marrow
IL-4 - IgE
IL-5 - IgA
IL-6 - produce acute-phase proteins

Question 12

Superantigen mechanism & what bacteria

Answer 12

Cross-link B region of T cell to MHC Class II of APCs, causing non-specific polyclonal activation of T-cells. Strep pyogenes & Staph aureus.

Question 13

Interferons big-picture mechanism

Answer 13

Innate defense. Glycoproteins secreted by virally infected cells & act on NON-infected cells to inhib protein synthesis & degrade mRNA -> apoptosis & inhib viral amplification

Question 14

CD16 & CD56

Answer 14

NK cells

Question 15

CD3

Answer 15

T cells

Question 16

CD4

Answer 16

Helper T cells

Question 17

CD8

Answer 17

Cytotoxic T cells

Question 18

CD19, CD20

Answer 18

B cells

Question 19

Live attenuated vaccine Pros & Cons

Answer 19

Activate cellular response. Lifelong immunity. May revert to original pathogenic form -> contraindicated in pregnancy & immunocompromised

Question 20

Inactivated/killed vaccine Pros & Cons

Answer 20

Activate humoral response. Need booster shots. Stabler & safer.

Question 21

Type 1 Hypersensitivity

Answer 21

IgE mediated. Fast because of preformed Ab & protein (histamine).

Question 22

Type 2 Hypersensitivity

Answer 22

Cytotoxic T-cells & complement mediated (IgG & IgM). Auto-immunity is due to similarity of antigen to self.

Question 23

Type 3 Hypersensitivity

Answer 23

Immune complexes mediated. Cause serum sickness (transient 5-10 days reaction due to Ab production to foreign proteins) and Arthus reaction (localized reaction to vaccines)

Question 24

Type 4 Hypersensitivity

Answer 24

Delayed T-cells mediated, NOT Ab, upon sensitization. Cause transplant rejection, contact dermatitis & mechanism of TB skin test.

Question 25

TLRs & PAMPs

Answer 25

Toll-like Receptors on innate immunity cells that recognize Pathogen-Associated Molecular Patterns such as LPS (gram-), flagellin, and ssRNA (viruses)