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
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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
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What do TCRs recognize?
Peptide Ags only
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What is the role of T helper cells?
Produce cytokine IFN-gamma to stimulate macrophages to destroy microbes in phagosome
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What is the role of CTLs
Kill infected cells
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What cell types are considered professional APCs?
DCs, macrophages and B cells
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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
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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
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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
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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
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What cell types express the TCR and class I MHC, but not class II MHC or BCRs?
T cells
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What cell types express BCRs and both class I and class II MHC molecules, but not TCRs?
B cells
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What cell types express class I MHC only?
Granulocytes
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What cell types do not express MHC, BRCs or TCRs?
Erythrocytes
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Microbial Ags are taken up by professional APCs via ____________ by macrophages or _____________ by DCs and B cells
Phagocytosis; endocytosis
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Are Ag-free MHC molecules displayed on APCs?
No! No Ag-free MHC molecules are displayed on APCs
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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
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The variable region of an Ab confers ________________
Ag recognition
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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
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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
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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
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