Immuno

Question 1

What part of the spleen is non-immunologic? Functions?

Answer 1

Red pulp; filter debris from blood, convert Hgb to bilirubin, reutilize Fe

Question 2

What part of the spleen is immunologic? Where are T cells found? Where are B cells found?

Answer 2

White pulp; PALS around central arteriole; primary and secondary follicles

Question 3

Main product of primary and secondary follicles (spleen)?

Answer 3

Antibodies, especially IgM

Question 4

How do T cells acquire T cell receptor (TCR)?

Answer 4

In the thymus, by interacting with cortical thyme horses like thymosin, thymulin, and thymopoietin

Question 5

Where are M cells found? What pathogen can transverse them? Where does it then reside?

Answer 5

Overlying Peyer’s Patches in intestine; Salmonella; macrophages

Question 6

What recognizes LPS?

Answer 6

TLR-4

Question 7

What pathogens possess double-stranded RNA?

Answer 7

Viruses (uniquely)

Question 8

What do interferons do, broadly?

Answer 8

Confer resistance to adjacent, uninfected cells

Question 9

What can NK cells do?

Answer 9

Target and kill virally infected and cancer cells

Question 10

What cells display MHC I?

Answer 10

All nucleated cells in the body

Question 11

What cytokines are seen early on during viral infection

Answer 11

IFN-a, IFN-b, TNF-a, IL-12

Question 12

What 2 cellular changes elicit targeting from NK cells?

Answer 12

Loss of MHC I, over expression of stimulatory ligands

Question 13

How do NK cells and CD8+ T cells provide “reciprocal coverage”?

Answer 13

NK cells target cells that stop expressing MHC I, whereas CD8+ cytotoxic T cells use MHC I to recognize epitopes

Question 14

What interferons are anti-viral? What effect do they have?

Answer 14

Type I interferons: IFN-a and IFN-b; incr. expression of MHC class I

Question 15

What interferons are anti-bacterial? What effect do they have?

Answer 15

Type II interferons: IFN-gamma (produced by leukocytes); incr. expression of MHC I and MHC II

Question 16

Describe the interferon response to virally-infected cells

Answer 16

IFN-a and IFN-b: induce resistance to viral replication in cells, incr. expression of ligands for NK cell receptors, activate NK cells

Question 17

IL-7 function

Answer 17

B cell survival

Question 18

What is CD25? Where is it found and what is its function?

Answer 18

Surface molecule on T cells; double negative T cells; IL-2 receptor, important for development

Question 19

What is CD3 responsible for?

Answer 19

Intracellualr signaling (on T cells); necessary for TCR to bind MHC (functional receptor includes TCR + CD3)

Question 20

What is AIRE? What does it do?

Answer 20

AutoImmune REgulator transcription factor; forces extrathymic proteins to be expressed in the thymus so that T cells that react with self components with a high affinity will be deleted

Question 21

Define toxoid

Answer 21

Inactivated toxin

Question 22

What happens in the “dark zone” of the germinal center wishing secondary lymphoid tissues?

Answer 22

Proliferation of B cells, somatic hypermutation

Question 23

What happens in the “basal light zone” of the germinal center wishing secondary lymphoid tissues?

Answer 23

Positive selection for binding to antigen on follicular dendritic cells

Question 24

What happens in the “apical light zone” of the germinal center wishing secondary lymphoid tissues?

Answer 24

Production of memory B cells and plasma cell precursors, class switching

Question 25

Which immunoglobulins are polymers?

Answer 25

IgM (pentamer), IgA (dimer)

Question 26

Which complement proteins are not involve in the alternative pathway?

Answer 26

C1, C4

Question 27

IgG function

Answer 27

Most abundant, secondary response, IgG1 and IgG3 are cytophilic, classical complement activation, crosses placenta

Question 28

IgM function

Answer 28

Primary response, classic complement system, produced in blood borne infections

Question 29

IgA function

Answer 29

The secreted immuglobulin: present in tears, saliva, feces, breastmilk; functions in neutralization

Question 30

IgE function

Answer 30

Binds Fc receptor on Mast cells and basophils, atopic diseases (allergy and asthma), immunity to helminths

Question 31

Where is B7 found and what does it do?

Answer 31

Co-stimulatory molecule on dendritic cells binds CD28 on naive T cells for the 2nd step of activation

Question 32

Where is CD28 found and what does it do?

Answer 32

Co-stimulatory molecule on T cells binds B7 on dendritic cells for the 2nd step of activation (can also bind CD80, a member of B7 family)

Question 33

2 steps of T cell activation

Answer 33

1st: recognition of MHC-Ag complex by TLR 2nd: "co-stimulation" binding of dendritic B7 or CD80 to T cell CD28

Question 34

IL-2 function

Answer 34

"Drives T cell division" - IL-2 acts in an autocrine and paracrine fashion to incr. production of IL-2 and expression of IL-2 receptor (CD25); in addition activated T cells incr. the affinity of their IL-2 receptors

Question 35

Th1 cell responsibilities

Answer 35

Make macrophages better killers via IFN-gamma (also secrete IL-2), produce opsonizing Ab such as IgG, "intracellular killers" of intracellular bacteria and viruses, and a smaller role in B cell activation

Question 36

Th2 cell responsibilities

Answer 36

Help B cells make Ab (via IL-4 and IL-5) by expressing CD40 in response to antigen recognition, which binds CD40 on B cells, causing proliferation and differentiation into plasma cells (also induce mast cells and basophils = allergy connection)

Question 37

Describe reciprocal inhibition by Th cells

Answer 37

Th1 secretes IFN-gamma which inhibits Th2 cells; Th2 cells produce IL-10 which inhibits production of IFN-gamma by Th1 cells

Question 38

Which cytokines are classified as lymphotoxins? What cells produce lymphotoxins? What is their effect?

Answer 38

LT, TNF-b; Th1 and CTL cells; activation and induction of NO production in macrophages

Question 39

IL-3 function

Answer 39

Growth factor for progenitor hematopoietic cells

Question 40

GM-CSF function

Answer 40

Incr. production of granulocytes, macrophages and dendritic cells

Question 41

What type of T cell retains its memory better?

Answer 41

CD8+ cytotoxic T cells

Question 42

Th1 cell cytokine profile

Answer 42

IFN-gamma, IL-2, IL-3, TNF-a, TNF-b, GM-CSF, LT

Question 43

Th2 cytokine profile

Answer 43

IL-4, IL-5, IL-9, IL-10, IL-13, TGF-b

Question 44

Cytotoxic T cell cytokines profile

Answer 44

LT, IFN-gamma

Question 45

What cells display MHC class II?

Answer 45

Macrophages, dendritic cells, B cells, and epithelial cells of the thymus

Question 46

Describe the structure of MHC class I

Answer 46

Homotrimer (3 alpha chains) with beta-2 microglobulin attached for stability

Question 47

Describe the structure of MHC class II

Answer 47

Heterodimer (alpha and beta chains)

Question 48

TAP function

Answer 48

Allows cytoplasmic antigens into the ER so they can be loaded onto MHCI

Question 49

What MHC type presents cytosolic antigens?

Answer 49

MHC class I (remember association with viruses)

Question 50

What MHC type presents phagocytosed antigens?

Answer 50

MHC class II

Question 51

What MHC type presents antigens ingested by receptor-mediated endocytosis (e.g. by B cells)?

Answer 51

MHC class II

Question 52

Name a virus that attacks TAP

Answer 52

HSV-1

Question 53

CLIP function

Answer 53

Stabilize MHCII and prevent binding of "wrong" peptide

Question 54

HLA-DM function

Answer 54

Facilitate swap of CLIP for antigen on MHCII