Lecture 7: Introduction To Immune System Flashcards Preview

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Flashcards in Lecture 7: Introduction To Immune System Deck (62):
1

The humoral response is mediated by Abs produced by B lymphocytes and responds to ____________ pathogens, whereas the cell-mediated response is mediated by thymus-dependent lymphocytes called T lymphocytes and responds to _____________ pathogens

Extracellular; intracellular

2

______ lymphocytes develop from precursors during lifetime

B

3

All _____ lymphocytes are generated in the ___________ early in life

T; thymus

4

What do BCRs recognize?

Various Ags: Proteins, carbs, lipids and nucleic acids

5

B cells (plasma cells) produce Abs that are secreted into the ____________ and ___________ fluids

circulation;mucosal

6

What do TCRs recognize?

Peptide Ags only

7

What is the role of T helper cells?

Produce cytokine IFN-gamma to stimulate macrophages to destroy microbes in phagosome

8

What is the role of CTLs

Kill infected cells

9

What cell types are considered professional APCs?

DCs, macrophages and B cells

10

What is the role of professional APCs?

When activated, professional APCs activate both T helper and CTLs

- They are not killed and continue Ag presentation for other cells

11

What cell types are considered non-professional APCs?

Any nucleated cell in the body


12

When infected with intracellular pathogens, non-professional APCs activates only _____________ lymphocytes which kill the infected non-professional cell

Cytotoxic T

13

When Ags are captured by APCs, microbes enter through an epithelium and are captured by ________ resident in the epithelium. These cells then transport Ags to the ____________ where protein Ags are displayed for recognition by T lymphocytes.

DCs; lymph nodes

14

Blood borne Ags are presented by APCs in the _________

Spleen

15

What professional APCs carry microbial Ags out of the lymph nodes?

DCs

16

APCs resent Ags to T lymphocytes congregated in the special areas called __________ zones

T cell

17

What delivers Ags to B cells and where?

Lymph! (Not DCs); delivers Ags to B cells congregated in the special areas called B cell zones

18

Each splenic arteriole is surrounded by the ______________ _______________ sheath

Periarterial lymphoid sheath (PALS)

19

PALS contains T cell and B cell zones and is attached to follicle containing a _____________ ___________

Germinal zone

20

The PALS and lymphoid follicles together constitute what?

The white pulp

21

White pulp is surrounded by the __________ ___________ which is rich in vascular sinusoids

Red pulp

22

_________________ APCs express class I MHC only

Non-professional

23

_______________ APCs express both class I and class II MHC

Professional

24

What cell types express both class I and class II MHC, but not the TCRs or BCRs?

Macrophages and DCs

25

What cell types express the TCR and class I MHC, but not class II MHC or BCRs?

T cells

26

What cell types express BCRs and both class I and class II MHC molecules, but not TCRs?

B cells

27

What cell types express class I MHC only?

Granulocytes

28

What cell types do not express MHC, BRCs or TCRs?

Erythrocytes

29

Microbial Ags are taken up by professional APCs via ____________ by macrophages or _____________ by DCs and B cells

Phagocytosis; endocytosis

30

Are Ag-free MHC molecules displayed on APCs?

No! No Ag-free MHC molecules are displayed on APCs

31

An Ab is a tetramer of 2 pairs of identical ________ and _______ chains

Heavy and light

32

Both heavy and light chains of an Ab have __________ and ___________ domains

Variable and constant

33

The variable region of an Ab confers ________________

Ag recognition

34

The heavy chain of an Ab contains a _________ domain that confers flexibility to allow optimal Ag binding

Hinge

35

The _________ region, termed Fc, determines the effector property of Abs

Constant

36

Distinct biological activities attributed to each heavy chain molecule of an Ab via their unique _________ part

Fc

37

What are the various types of heavy chains of Abs?

Gamma, alpha, mu, epsilon, delta

38

What are the different types of light chains of Abs?

Kappa and lambda

39

The Ag-binding fragment obtained by proteolysis with ___________ contains 2 Ag-binding sites termed Fab fragments and Fc fragment

Papain

40

The Ag-binding fragment obtained by proteolysis with __________ contains 2 Ag-binding sites and is termed F(ab')2

Pepsin

41

Abs are classified according to their _________ chains

Heavy

42

How many subclasses does IgG have?

4: IgG1, IgG2, IgG3, IgG4

43

How many subclasses does IgA have?

2: IgA1 and IgA2

44

What Ab is a dimer in the secreted form?

IgA

45

What Ab is a pentamer in the secreted form?

IgM

46

Where does IgA mainly act?

Mucosal immunity and neonatal passive immunity

47

What Ab is the naive B cell Ag receptor?

IgD

48

What Ab causes mast cell activation?

IgE

49

What Ab is responsible for opsonization, complement activation, Ab-dependent cell-mediated cytotoxicity, neonatal immunity and feedback inhibition of B cells?

IgG

50

What Ab is a naive B cell Ag receptor and activates the complement

IgM

51

Which Ab is highest in the serum?

IgG

52

What are the 6 effector mechanisms of antibodies?

Neutralization
Agglutination
Activation of complement
Opsonization
Ab-dependent cell-mediated cytotoxicity (ADCC)
Degranulation

53

Explain the antibody effector mechanism of agglutination

Cross-linking occurs because Abs possess 2 identical Ag-binding sites -> microbes can be agglutinate into mesh-like structures called immune complexes

54

Explain the antibody effector mechanism of opsonization

Abs can bind to Fc receptors on macrophages and neutrophils that enhances phagocytosis

55

Explain the Ab effector mechanism of Ab-dependent cell-mediated cytotoxicity (ADCC)

Fc receptors on NK cells -> Ab-tagged killing of tumor cells and virus-infected host cells

56

Explain the Ab effector mechanism of degranulation

Degranulation of mast cells, basophils and eosinophils - IgE binding to Fc receptors on the cells

57

A 23-year-old woman had been having diarrhea for 3 days. She reports to her primary care physician and he does an endoscopy. She notes that the outermost layer of her luminal surface is missing. What is this layer?
A) Goblet cells
B) Lamina propria
C) Microvilli
D) Simple columnar epithelium
E) Villi

C) Microvilli

58

All of these features are false about the spleen except:
A) Macrophages sheathe the radial arteries in order o remove damaged RBCs and debris
B) Penicillar arteries feed the marginal zone sinuses of the white pulp
C) Red pulp is made of RBCs, includes a marginal layer and a germinal center
D) Blood flow originates from the splenic Avery, flowing eventually into penicillar arteries that either feed into splenic sinusoids or red pulp
E) The spleen is made up of an outer cortex and 2 main compartments, Red and white pulp

D) Blood flow, originates from the splenic artery, flowing eventually not penicillar arteries that either feed into splenic sinusoids or red pulp

59

While observing keratinocytes in a blown up picture of your patient you notice oval nuclei, lots of desmosomes and spine-like processes. You know these keratinocytes come from:
A) Stratum basale
B) Stratum corneum
C) Stratum granulosum
D) Stratum spinosum
E) Stratum lucidum

D) Stratum spinosum

60

While hurrying over to Smith Hall to reserve a room for your intense test preparation you scrape your knee after taking a nasty fall on the slippery sidewalk. Normally you would yell in pain, however you know the process of wound healing and begin to formulate in your head that:
A) The first step involves inflammation and recruitment of a mass number of neutrophils via chemokines
B) Keratinocytes from the surrounding stratum granulosum and stratum spinosum layer create a bridge in the development of new skin under the scab
C) Migration occurs by detachment of hemidesmosomes while the underlying dermis contracts to bring edges of the wound together
D) PDGF is released from he cleavage from fibrinogen to form fibrin in order to recruit more platelets

C) Migration occurs by detachment of hemidesmosomes while the underlying dermis contracts to bring edges of the wound together

61

In the body a barrier regulates exchange of substances between the circulatory system and thymus, providing a sequestered environment for immature T cells to develop. The barrier also prevents the immature T cells from contacting foreign Ags. Where is this barrier located?

In the peripheral cortex of the thymus

62

Which of the following splenic arteries are surrounded by a very thin perilymphatic sheath (PALS) that disappears as the arteries in a brush-like pattern that ramify gradually into capillaries upon entering the red pulp?
A) Central arteries
B) Left gastroepiploic
C) Penicillar arteries
D) Radial arteries
E) Short gastric arteries

C) Penicillar arteries