Download Immuno Exam 2 LECTURE 11 1. Activation of T cells requires what? A

Immuno Exam 2
LECTURE 11
1. Activation of T cells requires what?
A: Recognition of Ag displayed by APC
2. What are the two functions of the adaptive immune response?
A: Help innate cells be better at clearing pathogen and set up a memory response and
establish that response in certain tissue
3. What is the most potent APC?
A: Dendritic cells
4. What are the other two forms of APC?
A: Macrophages and B cells
5. Describe signal 1 in T cell activation.
A: An immature (non-activated) APC has a microbial/viral peptide bound to its MHC class I.
The T cell receptor (TCR) binds to the MHC class I. This sends a signal to the T cell. The
presence of PAMP and/or an innate cytokine (“danger molecule”) promotes costimulatory
molecule expression by APC
6. Describe Signal 2 in T cell activation.
A: The costimulatory molecule, B7/CD80/CD86, on the APC binds with CD28 on the T cell.
7. Describe Signal 3 in T cell activation.
A: The presence of a pathogen or innate cytokines induces cytokine production by APC,
which go and bind to cytokine receptor on T cell, thus activating the T cell
8. What is the purpose of signals 1 and 2? What is the purpose of signal 3?
A: Create proliferation; required for T cell survival and differentiation into active effector
cells
9. What is the “Signal 3” that leads to Th2 production? What is Th2 cells function?
A: IL-4; Initiate Ig production/Helminth immunity
10. What is the “Signal 3” that leads to Th1 production? What is Th1 cells function?
A: IL-12; activate macrophages/intracellular microbe immunity
11. What is the “Signal 3” that leads to Th17 production? What is Th17 cells function?
A: IL-6 + TGF-B; extracellular bacteria and fungi immunity
12. What are MHCs of humans termed?
A: Human Leukocyte Antigens (HLA)
13. What is the function of MHC Class I molecules?
A: Present peptide Ags to activate CD8+ T cells
14. What are the MHC Class I designations?
A: HLA-A, HLA-B, and HLA-C
15. These genes encode regions of the…alpha or beta chain?
A: alpha
16. The alpha chain combines with what for all MHC Class I molecules?
A: β2-microglobulin
17. What are the “Non-classical” MHC Class Ib molecules?
A: HLA-E, HLA-F, HLA-G
18. What is the function of HLA-E?
A: Binds peptides as HLA Class I. Also, engages NK cells and can either inhibit by
interaction with NKG2A/NKG2B or stimulate by interaction with NKG2C.
19. What is the function of HLA-F? Where is it found?
A: Binds a restrictive set of Ags. Localized to the ER and Golgi with limited surface
expression
20. What is the function of HLA-G?
A: It is an inhibitory molecule that prevents mother immune cells from killing fetus
21. What are the “Non-classical” MHC Class Ic molecules?
A: MICA and MICB
22. Where are they found? How do they function?
A: They are found only in stressed cells. They override the inhibitory signal from MHC I in
NK cells resulting in activation.
23. What does MIC lack that the other MHC Class I have?
A: β2-microglobulin
24. What is the function of MHC Class II molecules?
A: Present peptide Ags to activate CD4+ T cells
25. What are MHC Class II molecules designation?
A: HLA-DP, HLA-DQ, HLA-DR, HLA-DM, HLA-DO
26. HLA Class II molecules consist of what chains?
A: One alpha and one beta
27. What chains does HLA-DP consist of? Which chain shows higher polymorphism?
A: Single alpha (DPA1) and beta (DPB1) chain genes; DPB1
28. What chains does HLA-DQ consist of? What degree of polymorphism do they show?
A: Two pair of genes for both alpha & beta chains (DQA1, DQA2; DQB1, DQB2); moderately
polymorphic
29. What chains does HLA-DR consist of? What degree of polymorphism do they show?
A: Single alpha chain gene (DRA) – ALL DR molecules have this chain and Multiple beta
chain genes (DRB1-9); DRA—low polymorphism, DRB—high polymorphism
30. What chain can lead to many autoimmune diseases?
A: DRB
31. What kind of dominance does MHC genes inherited by parents show?
A: Co-dominance
32. What chromosome possesses all the MHC genes?
A: chromosome 6
33. What are the cells that express MHC Class II?
A: Professional APCs, macrophages, and B cells
34. What are the cells that express MHC Class I?
A: All nucleated cells
35. What is MHC restriction? Where does this occur in development?
A: T cells recognize specific Ags only when displayed on self MHC molecules; imprinted in T
cells during thymic development
36. Which MHC Class is closed ended? How many amino acids does it recognize?
A: Class I; 8-11 amino acids
37. Which MHC Class is open ended? How many amino acids does it recognize?
A: Class II; 10-30
38. List some MHC/Peptide binding characteristics.
A:
 Bind only one peptide at a time
 Peptides acquired during intracellular assembly
 There is a broad specificity
 There is a very slow off-rate
 Stable expression requires a peptide
 MHC molecules bind ONLY peptides
39. Describe the MHC Class I production pathway.
A: Viral proteins are ubiquinateddegraded into peptides by proteasomepeptides
transported from cytosol to ERTAP directs cytosolic peptides into ERERAP trim
cytosolic peptides to fit into MHC Class Iassembly of peptide class I complexes in
ERcomplexes sent to golgi where packagedReleased in exocytic vesicle to be bound to
cell membrane
40. The MHC Class II production pathway occurs only in what cells?
A: Professional APCs
41. Describe the MHC Class II production pathway.
A: Protein antigen endocytosedprocessing of internalized proteins in
endosomal/lysosomal vesiclesMHC Class II produced in ER and stabilized by Ii (invariant
chain)sent to golgi where packaged and released in an exocytic vesicleHLA-DM
degrades invariant chain and CLIP to allow peptide bindingAssociation of processed
peptides with MHC Class II molecules in vesiclesvesicle binds with membrane for
expression of peptide-MHC complex
42. What is the importance of HLA-DM in the MHC Class II pathway?
A: It allows for the removal of Ii and CLIP and stabilizes MHC Class II for peptide binding
43. What is cross-presentation?
A: Taking exogenous pathogens and bringing them into DC and breaking them down for
CD8+ T cells
44. How do monocytes and lymphocytes cross present Ags? Describe the mechanism
A: Using HLA-F; Cell surface MHC I (without peptide) captures exogenous AgHLA-F
stabilizes Ag capture MHC I-Ag & HLA-F internalized in endosome which fuses w/
lysosomeAg is trimmed to peptide, which binds to MHC Class I HLA-F transfers β2microglobulin to MHC I-peptide complexMHC-peptide shuttled to surface for Ag display
45. What is cross-dressing?
A: DC can pass of entire MHC-I molecule to LN resident DC, which leads to memory of
immunity against that Ag
46. CD8+ T cells bind to what chain of MHC I molecules during Ag presentation? CD4+ T cells bind to
what chain of MHC II molecules during Ag presentation?
A: alpha-3; beta-2
LECTURE 12
1. B lymphocytes lead to what form of immunity?
A: Humoral
2. T lymphocytes lead to what form of immunity?
A: Cell-mediated
3. Where do B cells develop?
A: In the bone marrow
4. B cells develop where in the bone marrow?
A: On the surface of bone marrow stromal cells
5. What cytokine is the survival factor for B cells?
A: IL-7
6. What regions do the heavy chain consists of?
A: V, D, and J
7. What regions do the light chain consists of?
A: V and J
8. What is the process of heavy chain BCR development?
A:
 The early pro-B cell undergoes D-J rearrangement
 Successful D-J triggers V arrangement in the late pro-B cell. (V-DJ rearrangement)
 VDJ rearrangement is successful, which leads to Pre-B cell to express a partial BCR
9. What enzyme leads to the DNA excision and RNA splicing in gene rearrangement of heavy chain?
A: VDJ recombinase
10. What is the process of light chain BCR development?
A:
 Light chain genes activated leading to V-J rearrangement in small pre-B cells
 Successful light chain rearrangement of VJ results in BCR expression (m heavy
chain, k or l light chain)
 IgM expressed on surface
11. What is the major characteristic of mature B cells?
A: They coexpress IgD and IgM
12. Coexpression of IgD and IgM are made possible by what?
A: mRNA alternate splicing
13. 85% of BCR light chain is what? 15%?
A: kappa; lambda
14. Successful rearrangements maintain what receptor expression? What happens if they lose this
expression?
A: IL-7; apoptosis
15. What is allelic exclusion?
A: The process in which one of the two genes for which an individual is heterozygous is
expressed, while the other gene is excluded
16. BCR diversity is generated by what?
A: Recombinase
17. Where are Recombination Recognition Sequences (RRS) located?
A:
 3’ end of V gene segments
 5’ end of D gene segments
 3’ end of D gene segments
 5’ end of J gene segments
18. What is a heptamer and what is its function?
A: It is a highly conserved stretch of 7 nucleotides adjacent the coding sequence; enhances
binding of RAG recombinase to RRS and specifies site of DNA cleavage
19. What is a nonamer?
A: The binding site to anchor RAG to DNA
20. What is the function of the spacer?
A: Provide efficient V(D)J recombination by properly aligning the heptamer and nonamer
21. The beta chain refers to what in the BCR/TCR? Alpha chain?
A: heavy chain; light chain
22. What are the two enzymes involved in junctional diversity and what do they do?
A: TdT—terminal deoxynucleotidyl transferase: adds N-nucleotide to H chain; Polm—DNA
polymerase mu: adds N-nucleotides to L chain
23. What do surviving B cells express that traffic them to secondary lymphoid organs?
A: CXCR5
24. Where do T cells develop TCR?
A: Thymus
25. What chain first undergoes rearrangement in TCR? Describe TCR rearrangement.
A: beta; DJ rearrangement occurssuccess triggers V-DJ rearrangementconstant (C2)
region is spliced to rearranged VDJ following transcriptionPre-TCR expressedalpha
chain rearrangement promotedTCR is expressed on T cell surface
26. Describe the selection process that follows TCR rearrangement.
A: TCR upregulates CD4 and CD8weak or no binding to CTEC MHC leads to apoptosis,
however moderate to strong binding to CTEC MHC allows the T cell to live
27. What occurs to the surviving T cells?
A: They will then express either CD4 or CD8. In the MTEC they encounter dendritic cells
that present self-antigen. Tight binding of the T cell leads to apoptosis, moderate binding
allows the T cell to live. Naïve mature T cells exit the thymus and move to the periphery.
28. True or False. T cells with successful gamma/delta rearrangement usually express their function
TCR and remain DN T cells?
A: True
29. Surviving T cells express what and traffic to the secondary lymphoid organ?
A: CCR7
LECTURE 13/14
1. What is the goal of cell-mediated immunity?
A: To eliminate intracellular pathogens
2. What phosphorylates tyrosines in the immunoreceptor tyrosine-based activation motif (ITAM)?
A: Lymphocyte-specific protein tyrosine kinase (Lck)
3. What releases Lck from CD4/8?
A: Ag recognition
4. Phopshorylated ITAMs recruit what molecule? What is this molecules function?
A: ZAP-70; it binds to phosphotyrosines and phosphorylates adaptor proteins, including
LAT (linker for activation of T cells)
5. Phosphorylated LAT activates what pathway and what molecule?
A: Ras pathway and Phospholipase C (PLC)
6. PLC activates what two mechanisms?
A: IP3, which increases Ca2+ in the cytosol and Protein Kinase C (PKC)
7. What is the function of PKC in cell-mediated immunity?
A: It phosphorylates IkB, which releases NF-kB that moves into the nucleus and promotes
production IL-2
8. What is the function of glucocorticoids?
A: Block NF-kB activation, inhibit Lck action, and suppress TCR calcium signaling
9. How does NF of activated T cells (NFAT) lead to IL-2 production?
A: Calcium ions bind to calmodulinCalmodulin activates calcineurinCalcineurin
removes phosphate from NFATNFAT migrates to nucleus to promote IL-2 production
10. What is the function of cyclosporine?
A: To inhibit calcineurin activity
11. Why is cyclosporine used in transplant patients?
A: To inhibit the activation of T cells against the new organ
12. What is the function of the Ras/Rac-MAPK (AP-1) pathway?
A: c-Fos and c-Jun form transcription factor AP-1 (activating protein-1), which enhances
transcription of several genes
– Differentiation (cytokines)
–
–
Proliferation
Apoptosis (Fas ligand)
13. What does stimulation of T cells by IL-2 leads to?
A: Clonal expansion, survival, and differentiation
14. What happens in clonal expansion?
A: T cells proliferate about 100,000-fold
15. What happens for survival?
A: IL-2 induces expression of anti-apoptotic proteins, BcI, and increases gene expression of
CD25 (IL-2 receptor)
16. How does IL-2 lead to differentiation?
A: IL-2 promotes gene expression of CD40 ligand and cytokine recpetors for Th1 and Th2.
17. What is the function of CD69?
A: It stabilizes the T cell-DC engagement to ensure signal 3 acquisition. It is an activation
marker of the adaptive immunity
18. What is the function of CD40 ligand?
A: It is critical for the development of antibody responses
19. What is the function of CTLA-4?
A: It is released 3 days after T cell activation to regulate expansion
20. How does CTLA-4 function?
A: It has a greater affinity for CD28, than CD80/86 does. It strips the phosphate groups off
and shuts down proliferation.
21. What are the three groups of adhesion molecules employed by trafficking T cells to infiltrate
tissue? How do each function?
A:
 Selectin ligand—found on the T cell and binds to selectin molecules on injured
tissue epithelium
 Chemokine receptors—bind chemokines on proteoglycans that are released from
the damaged tissue
 Integrins—bind to integrin receptors on damaged tissue epithelium
22. What do T cells “spit out”, once adhered to tissue epithelium, in order to get to damaged tissue
area?
A: ECM proteases
23. Th1 cells develop with what cytokine’s help?
A: IL-12
24. Th2 cells develop with which cytokine’s help?
A: IL-4
25. Th17 cells develop with which cytokines’ help?
A: TGF-B and IL-6
26. Where does IL-4 come from in the lymphoid organs for Th2 development?
A: Activated Basophils
27. What are the Th1 cell effector functions?
A: Th1 cellIFNγmacrophage activation/IgG productionfight intracellular microbes
28. How does IFNγ enhance macrophage function?
A: IFNγ increases ROS/NO productions, inflammatory cytokines, and increase MHC Class I
expression of infected cell. It also promotes IgG production, which can opsonize microbe
and be recognized by NK cells for cell death
29. What are the Th2 cell effector functions?
A: Th2 cellIL-4, IL-5, IL-13Mast cell/eosinophil activation, IgE production, “alternative”
macrophage activationFight helminthic parasites/wound healing
30. How do IL-4, IL-5, and IL-13 enhance function?
A: IL-4 initiates antibody (IgG and IgE) production, IL-4/IL-13 stimulates GIT mucus
secretions and peristalsis (diarrhea), IL-5 enhances eosinophil function, and IL-4/IL-13
promote wound healing by activating alternative macrophages
31. What are the Th17 cell effector functions?
A: Th17IL-17 and IL-22neutrophilic/monocytic inflammationfight against
extracellular bacteria and fungi
32. What is IL-17 function?
A: It promotes inflammation and recruits neutrophils to infection
33. What is IL-22 function?
A: It promotes increased barrier function
34. What protects CD8 T cells from killing itself by release of perforin/granzyme?
A: serglycin
35. CD8 T cells kill by two methods…what are they?
A: Perforin/granzyme and Fas Ligand interacting with Fas on infected cell
36. What are the two death receptor pathways?
A: FasL-Fas and TNF-TNFR
37. What molecule can out compete caspase-8 and block apoptosis in the FasL-Fas death pathway?
A: c-FLIP
38. Describe the two Complex of TNF-TNFR pathway.
A: Complex I—TNF binds to TNFRTRADD+TRAF2+RIP1 bind to TNFRpromotes cFLIP/initiates NF-kB activationblocks apoptosis/inflammation; Complex II—Activated
TNFR1 is endocytosedTRADD/TRAF2/RIP1 complex dissociates TNFR
TRADD/TRAF2/RIP1 recruits FADD and caspase-8 (complex II) apoptotic machinery
activated (provided that the levels of cFLIP are low enough to remove inhibition)
39. Promotion of what cytokines in the mitochondrial death pathway induces anti-apoptotic BcI-2
protein expression?
A: IL-2, IL-7 and growth factors
40. What is BcI-2 proteins function?
A: Bind Bim, which prevents Bax and Bak oligomerization (apoptosis)
41. Development of CD8+ T cell responses depends on what cytokine?
A: IL-2
42. Where are central memory T cells located? Effector memory T cells?
A: Remain in lymph node; traffic to tissues
43. What cytokine drives expansion of memory T cells? Survival?
A: IL-15; IL-7
44. Describe the relationship of the levels of IL-7R, IL-2R, and IL-15R as naïve, activated, and
memory maturation.
A:
Naive
Activated
Memory
 IL-7Rhi
IL-7Rlo
IL-7Rhi
 IL-2Rlo
IL-2Rhi
IL-2Rlo
mid
hi
 IL-15R
IL-15R
IL-15Rhi
LECTURE 15
1. What is the goal of humoral immunity?
A: eliminate extracellular pathogens and neutralize toxins
2. Antigen flows in to lymph nodes from tissue via what mechanism?
A: afferent lymphatics
3. What are the two types of B cells?
A: B-1 cells and B-2 cells
4. What are the two types of B-2 cells? Where are they found?
A: Follicular B cells and Marginal Zone B cells; Spleen
5. What are follicular B cells activated by?
A: Thymus-dependent antigen
6. What are marginal zone cells activated by?
A: They are thymus-independent antigens (polysaccharide, lipids, etc.)
7. Where are B-1 cells found?
A: Mucosal tissue and peritoneal cavity
8. What are B-1 cells activated by?
A: Polysaccharides, lipids, etc. (thymus-independent)
9. What are the transcription factors that result from BCR ligation signaling?
A: NFAT, NF-kB, AP-1
10. What does syk (in B cells) correspond to in T cells?
A: ZAP-70
11. What is the functional response induced by antigen-mediated cross-linking of the BCR complex?
A: Proliferation and anti-apoptotic factors
12. What is the response of activation of B-lymphocytes?
A: expression of antigen presentation machinery; MHC Class I and II and B7 (CD80/CD86)
13. What follows the expression of antigen presentation machinery?
A: Expression of cytokine receptors—IL-2R, IL-4R, IL-5R, and IL-21R
14. What chemokine is expressed that directs migration of B cell to T cell zone?
A: CCR7 and down regulation of CXCR5
15. CXCR5+ naïve Th cells also express what? Where do these cells congregate?
A: CXCL13; interfollicular zone (area just outside the paracortex side of the follicle)
16. What activates Pre-TFH cells?
A: Resident DC
17. What does activation of T cell lead to?
A: CD40 ligand expression and cytokine secretion
18. What is the purpose of CD40 ligand?
A: It gives the antibody response
19. What cytokines do Pre-TFH cells secrete?
A: IL-2, IL-4, and IL-5
20. Where do activated Pre-TFH cells engage activated B cells?
A: The interfollicular zone
21. How do Pre-TFH cells induce/assist in B cell proliferation?
A: Secretion of cytokines and binding of CD40L
22. What does a defective CD40L expression result in?
A: X-linked hyper-IgM syndrome
23. What is the function of Activation Induced Deaminase (AID)?
A: It is required for Ig class-switch recombination and somatic hypermutation
24. What is somatic hypermutation?
A: A high rate of mutations that occur in the variable region of both heavy and light Ig
chains, which leads to selection of high-affinity B cells
25. What are the 3 major functions of Bcl-6?
A:
 It differentiates Th into TFH cells
 It stabilizes CD40L and CXCR5 expression
 It induces production of IL-21 and IL-21R expression (autocrine)
26. What is the function of IL-21/IL-21R?
A: It co-stimulates mature T and B cell proliferation and differentiation and also potentiate
NK cytolytic functions, inducing NK terminal differentiation
27. Where do B cells and TFH cells migrate once they are activated?
A: B cell zone and germinal centers
28. What occurs in the dark zone of germinal centers?
A: TFH IL-21 promotes robust proliferation and surface BCR diminish, thus forming
centroblasts
29. What are centrocytes?
A: They represent centroblasts that have completed somatic hypermutation and now
express a BCR
30. What occurs in the basal light zone of germinal centers?
A: Centrocytes engage FDC, which leads to affinity maturation
31. What must occur for centrocytes to avoid apoptosis?
A: Their BCR and CD21 must bind with high affinity to what the FDC is presenting.
32. What make up CD21 ligands?
A: cleaved C3 fragments of complement
33. What happens to the surviving centrocytes?
A: They engaged TFH cells and differentiate into plasma cells
34. What signals promote proliferation and differentiation of B cells into plasma cells?
A: CD40 and IL-21
35. When are short-lived plasma cells formed? What is their fate?
A: They are formed during initial TFH cell and B cell interaction in the interfollicular zone;
they undergo apoptosis as plasmablasts (precursor of long-lived PC) are generated
36. What is the function of memory B cells? Do they produce antibodies?
A: They serve as a reservoir for memory B cell responses/long-lived plasma cells. They can
differentiate into Ig-producing plasmablasts upon Ag encounter; No antibody production
37. Where are long-lived plasma cells found?
A: Inflamed/infected tissue or bone marrow
38. What do long-lived PC do in inflamed tissue?
A: They secrete high levels of Ig at Ag source site and undergo apoptosis as Ag decreases
39. What do long-lived PC do in bone marrow?
A: They never leave the marrow and constantly secrete low levels of Ig.
40. What plasma cells are the most important in vaccination?
A: Bone marrow long-lived PC
41. Which Ig are monomers?
A: IgG, IgE, IgD
42. Which Ig is a dimer?
A: IgA
43. Which Ig is a pentamer?
A: IgM
44. Which cytokines proliferate centroblast to centrocytes?
A: Il-2, IL-4, IL-5
45. IFN-γ leads to differentiation of centrocyte into plasma cells that secrete which Ig?
A: IgG1, IgG2, IgG3
46. TGF-β leads to differentiation of centrocyte into plasma cells that secrete which Ig?
A: IgA
47. IL-2, IL-4, and IL-5 lead to differentiation of centrocyte into plasma cells that secrete which Ig?
A: IgM
48. IL-4 leads to differentiation of centrocyte into plasma cells that secrete which Ig?
A: IgE and IgG4
49. What is isotype switching?
A: The switching of the C region of the heavy chain
50. What are 4 important reasons of isotype switching?
A:
 Response against nonprotein Ag
 Neutralization of virus and toxins
 Prevent mucosal colonization
 Eliminate parasitic helminthes
51. What is the process of IgMIgG1 isotype switch?
A: There are switch (S) regions between each of the C regions genesCD40 activates
AIDspecific cytokines and CD40 direct AID to selected S regions (SM and SG1)DNA in the
S regions is nickedA loop is formed between the two nicked DNA regions Loop cleaved
off and IgG1 is produced
52. Can isotype switch be reversed?
A: No
53. What are immune complexes (IC) composed of?
A: Secreted Ig bound to Ag
54. How is Ig production regulated?
A: IC are captured on B cells by FcR to activate phosphatase to remove phosphates from BCR
signaling proteins
55. What three ways can antibodies neutralize microbes?
A:
 Antibodies prevent the binding of microbes to cells and thus block the ability of the
microbes to infect host cells.
 Antibodies inhibit the spread of microbes from an infected cell to an adjacent
uninfected cell.
 Antibodies block the binding of toxins to cells and thus inhibit the pathologic effects
of the toxins.
56. What is the purpose of antibody opsonization of microbes?
A: Enhance phagocytosis
57. What cells demonstrate antibody-dependent cell cytotoxicity (ADCC)? What antibody do each
use?
A: NK cells—IgG and eosinophils—IgE
58. What is the function of IgG1-3?
A: Neutralization, opsonization, complement activation, ADCC, cross placenta
59. What is the function of IgG4?
A: Opsonization, ADCC, cross placenta
60. What is the most common serum Ig?
A: IgG1
61. Which IgG are the best at opsonization?
A: IgG1 and IgG3
62. What is the first Ig made in newborns?
A: IgM
63. What is the function of IgA?
A: Mucosal immunity and neutralization
64. What does the J chain of IgA do?
A: Provides structural stability and aids in translocation
64. Where does the secretory piece of IgA come from? What is its function?
A: Poly-Ig receptor on the basolateral surface; it protects the IgA from proteolysis
65. What is the function of IgM?
A: Complement activation, agglutination of microbes, opsonization
66. What are two important characteristics of IgM?
A: It is first Ig synthesized by B cells and the first BCR expressed on naïve mature B cells
67. What is the function of IgE?
A: Immunity to parasites and allergic responses
LECTURE 16
1. What does induction mean?
A: First detection
2. What is effector?
A: Response to induction
3. What are the top two worldwide deaths annually from mucosal infections?
A: Acute resp infections (4 million) and HIV (2.9 million)
4. What is the MALT?
A: Mucosa-associate lymphoid tissue. It is highly specialized immune system that protects
mucosal surfaces
5. What are the components (7) of the MALT?
A:
 Gastrointestinal tract (GALT)
 Bronchial tree (BALT)
 Nasopharyngeal area (NALT)
 Mammary gland
 Salivary and lacrimal glands
 Genitourinary organs
 Inner ear
6. What are the scattered lymphoid cells of the MALT? Organized lymphoid tissues?
A: Intraepithelial lymphocytes; Peyer’s patch
7. What is the effector site of the gut?
A: Lamina propria
8. What cytokine predominates in the Peyer’s patch?
A: TGF-β
9. What is Waldeyer’s ring?
A: An interrupted circle of protective lymphoid tissue at the upper ends of the respiratory
and alimentary tracts
10. What is the structure of mucosal immunity?
A: External environmentcontinuous epithelial cell layer sitting on a basement
membraneloose connective tissue (lamina propria)dense connective tissue that
connects mucosa with smooth muscle (submucosa)
11. What is found in the lamina propria?
A: Blood vessels, lymphatic vessels, and MALT
12. When can commensals become lethal?
A: If they cross the mucosal barrier and enter the circulation or traverse the intestinal wall
13. True or false. The GALT is an integral part in only innate defense.
A: False, innate and adaptive
14. How is the GALT an integral part of innate defense?
A: Produces chemokines, cytokines, and defensins
15. How is the GALT an integral part of adaptive defense?
A:
 Antigen uptake and transfer by M cells to DC
 Uptake and secretion of IgA
 Produce growth factors for IELs
16. What are mucins comprised of and what is their function?
A: They contain oligosaccharides and glycoproteins; They prevent microbial contact with
epithelial cell layer, serve as a matrix to capture and concentrate secreted defensins, she to
bind to bacterial pili, large amounts can form a glycocalyx to prevent attachment
17. What cytokines induce mucin synthesis?
A: IL-1, IL-6, TNF, Type I IFNs and PMN elastase
18. What part of the GALT immunity are mucins, defensins, and TLRs?
A: innate
19. What are defensins?
A: Small peptides that inhibit membrane synthesis
20. What cells produce defensins in the small intestine?
A: Paneth cells found in crypts
21. What cells produce defensins in the large intestine?
A: Intestinal epithelial cells
22. Which TLRs do intestinal epithelial cells express?
A: TLR 2, 4-7, and 9
23. Signaling through TLRs leads to what function?
A: Increased tight junction expression and proliferation of enterocytes
24. What TLR is mainly expressed on the basolateral surface of the intestinal epithelia? Why?
A: TLR4 so that if any commensals find their way through the epithelium and into the
lamina propria, they can bind them and signal a response. Don’t want them on lumen side
because that would lead to constant inflammation because of all the commensal and other
bacteria in the gut
25. What cytokine dominates in the GALT?
A: TGF-β
26. What cell is vital in the adaptive response of the GALT?
A: Microfold (M) cells
27. Where are M cells located?
A: The region that overlies the Peyer’s patches and other GALT structures
28. What are M cells function?
A: the transcellular transport of various substances from the lumen of the intestine across
the epithelial barrier to underlying APC.
29. Describe the process of M cell transcytosis.
A: M cell takes up antigen by endocytosis/phagocytosisantigen is transported across the
M cell in vesicles and released at the basal surfaceantigen is bound by DC, which activates
T cells
30. What are the two types of DC in the gut?
A: CD103- CD11b+ DC and CD103+ DC
31. What is the function of CD103- CD11b+ DC?
A:
 They can extend dendrites into the gut lumen and sample Ags
 Increased levels of bacterial ATP in gut lumen promotes IL-1, IL-6, IL-12, and TGF-β
production
32. What is the result of the microbial antigens and cytokine release by CD103- DC?
A: Th1 and Th17 cell differentiation
33. What is the function of CD103+ DC?
A: TSLP secreted by enterocytes upon NLR signaling
34. What production by CD103+ does TSLP promote?
A: TGF-β, IL-10 and retinoic acid
35. What are the functions of those cytokines in the gut?
A: Needed to make Treg cells
36. What is Foxp3+?
A: Transcription factor for Treg cells
37. What is the result of microbial response on CD103+?
A: Th2 and Treg cell differentiation
38. What are the two types of GALT T lymphocytes?
A: Lamina propria T cells and IEL T cells
39. What type of T cells predominate in lamina propria? What do they secrete?
A: CD4 γδ+ cells; secrete IFN-γ, IL-5, and IL-10
40. What types of T cells predominate in IEL? What is their function?
A: CD8 γδ+ cells; responds to low levels of Ag with perforin and granzyme and modulate the
kinetics of epithelial cell renewal
41. Which GALT T cells are the cells that promote chronic inflammation of IBD?
A: Lamina propria T cells
42. How do T cells enter Peyer’s patches from the blood vessels?
A: They are directed by homing receptors CCR7 and L-selectin
43. How do T cells become activated in Peyer’s patches?
A: They encounter antigen presented by DC
44. How do T cells return to the gut?
A: They drain from the mucosa via mesenteric lymph nodes to the thoracic duct and enter
the bloodstream. Their homing receptors guide them to where they belong in the gut
45. What must an activated T cell be expressing in order to home to the lamina propria and intestinal
epithelium of the small intestine?
A: CCR9 and α4:β7 integrin
46. Epithelial cells expressing MIC-A and MIC-B have undergone what signal?
A: Stress signal as a result of infection, damage, or toxic peptides
47. What is it on IELs that binds to MIC-A,B and activate the IEL?
A: NKG2D
48. What method does the IEL kill the stressed cell?
A: perforin/granzyme pathway
49. What must be present to signal differentiation of naïve T cells to T regs?
A: TGF-β
50. What cytokines lead to an isotype switching of and an increase in IgA?
A: IL-10 and TGF-β
51. What is the dominant class of Ig in MALT?
A: IgA
52. What is the structure of IgA in blood? In MALT?
A: monomer; dimer
53. What are the mechanisms of protection by IgA?
A:
 Inhibition of adherence
 Virus neutralization
 Neutralization of enzymes and toxins
 Immune exclusion and inhibition of antigen absorption
54. What does humoral response mean?
A: Immune response of PC producing Igs to fight microbes
55. What are the three methods of activity by IgA?
A:
 Secreted IgA on the gut surface binds and neutralizes pathogens and toxins
 IgA binds and neutralizes antigens in endosomes
 IgA exports toxins and pathogens from lamina propria while being excreted to
lumen
LECTURE 18
1. What are the settings requiring artificial immunity?
A:
 Patients with defective humoral immunity
 Exposure to a disease will likely cause complications
 Not adequate time between exposure and active immunization to protect
 Effects of a current infection can improve with immunization
2. What is the difference between passive and active artificial adaptive immunity?
A: Passive is transferring of Ig to assist with the opsonization/neutralization of a pathogen.
Active is providing a vaccination (active or inactive) of the antigen to allow the body to build
antibodies to fight the antigen if encountered
3. What is the immunization schedule of DTaP?
A: First dose—2 months old, second dose—4 months old, third dose—6 months old, fourth
dose—15-18 months old, fifth dose—4-6 years old
4. What is the immunization schedule of MMR?
A: First dose—12-15 months and second dose—4-6 years old
5. What delays the measles vaccine until 12-15 months of age?
A: Interference from maternal Ig binding to Ags
6. Why were multiple immunizations of polio vaccine used?
A: To ensure adequate immunity generated against the three strains of the poliovirus
7. What is the “Herd immunity” idea?
A: That if the majority of a population is immune to an agent, then the chance of a
susceptible individual contacting an infected person is very low.
8. What is thought to account for outbreaks of agents for which vaccines are available?
A: A decrease in herd immunity
9. What happened in the measles outbreak of the 1980s?
A: 88% of the people who fell ill were unvaccinated. Of those who had been vaccinated they
only received 1 vaccine. This led to recommendation for children to receive 2 MMR
vaccinations
10. What are the strategies of vaccine development? Describe.
A:
 Safety—vaccine must not cause illness or death
 Protection—vaccine must protect against illness resulting from live pathogen
exposure at point of entry




Sustained protection—protection must last several years to life of vaccine
Induce neutralizing Ig—effective protection from some pathogens requires preexisting Ig at time of exposure
Induce CMI—more effective elimination of pathogen, Ig production and memory
formation
Other—low cost, stability/storage, administration route, few side effects,
manufacturer cost
11. What are live, attenuated vaccines?
A: Microbes are cultured to lose the ability to cause significant disease but retain capacity
for transient growth in host. Microbes are grown for prolonged periods under abnormal
culture conditions and adapts to growth in other host cells and much less in human cells.
12. What was the discovery Jenner made from cowpox?
A: He found that some agents provide crossreactive protection from related pathogens.
During the smallpox epidemic, he saw that women who milked cows that had cowpox did
not obtain the smallpox virus. They only obtained small skin lesions from cowpox. Thus he
determined that there was a relationship between the cowpox and building immunity to
smallpox.
13. What are the diseases that can be vaccinated using live, attenuated vaccines?
A: measles, mumps, rubella, polio, rotovirus, TB, varicella, and yellow fever
14. What are some disadvantages of live, attenuated viruses?
A:
 Requires refrigeration
 May mutate to virulent form (reversion)
 Immunosuppressed patients cannot receive
15. What are some advantages of live, attenuated viruses?
A:
 Strong immune response
 Lifelong memory
 Few doses (due to transient growth)
16. What are inactivated or killed vaccines?
A: They are from microbes that are inactivated by chemical treatment (previously heat) so
the pathogen can induce immunity but has no capacity to replicate in the host
17. What are the diseases that can be vaccinated by inactivated or killed vaccines?
A: cholera, hep A, influenza, plague, polio, rabies
18. What are the advantages of killed vaccines?
A:
 No refrigeration required
 No threat of reversion
 Safe for immunosuppressed patients
19. What are the disadvantages of killed vaccines?
A:
 Weaker immune response
 Several doses to induce effective immunity
20. What are the forms of subunit (acellular) vaccines?
A: Toxoids, capsular polysaccharides, recombinant proteins
21. What does vaccination of toxoids lead to? What are example vaccines?
A: Neutralization of Ig; diphtheria and tetanus
22. What does vaccination of capsular polysaccharides lead to? What are example vaccines?
A: Opsonization of Ig; Streptococcus pneumonia and Neisseria meningitides
23. What is used as part of the recombinant protein vaccination?
A: Expressed Ags
24. What does vaccination with recombinant proteins lead to? What is an example vaccine?
A: Neutralizing and/or opsonizing Ig; Hep B virus vaccine
25. What are the diseases that can be vaccinated by acellular vaccines?
A: Diphtheria, tetanus, Hep B, Pertussis, Strep. Pneumonia
26. What are the disadvantages of acellular vaccines?
A: Require adjuvant for immune response and they are difficult to produce
27. What are the advantages of acellular vaccines?
A:
 Immune system targeted to recognize toxin
 Specific Ags used so low chance of adverse reactions
 Safe for immunosuppressed patients
28. What are adjuvants?
A: They are substances that enhance the immunogenicity of Ags. They often contain
aluminum salts, which bind to the toxoid to stimulate Ig response
29. What is responsible for increase Ag uptake and processing, MHC Class II, CD40 and CD86 (B7)?
A: Aluminum salts
30. What immune cells do most adjuvants act on to mature?
A: APCs
31. What are conjugate vaccines?
A: Polysaccharides that are conjugated to protein carriers to provide a good antibody
response.
32. True or False. Conjugate vaccines induce B cell memory and T cell memory responses.
A: False, no T cell memory response
33. Describe how the conjugate vaccine works.
A: The BCR is specific for the polysaccharide region of the conjugatethe conjugate is
internalized and processedpeptides from the protein component are presented to the T
cellT cell provides help to the B cell by CD40L binding to CD40the B cell produces
antibodies against the polysaccharide region of the pathogen
34. What are DNA vaccines?
A: Proteins expressed in vivo from bacterial plasmids encoding proteins for gene therapy
35. How are DNA vaccines delivered?
A: Gene gun
36. What do DNA vaccines include?
A: One microbe gene that includes cytokine genes, which activate APC and improve
immunogenicity of Ags
37. How are most vaccines given?
A: IM injection
38. What are the disadvantages of injections?
A:
 Painful and expensive
 Unpopular with the recipient
 Mass vaccination by injection is tedious
 Injection may not be most effective way of stimulating an appropriate response as it
does not mimic the usual route of entry
39. What administration has become the main focus of delivery?
A: Nasal or oral mucosal administration
LECTURE 19
1. What does test for the presence of antigens lead to?
A: Diagnosis of disease
2. What does testing for the presence of antibodies or cells lead to?
A: Determining how well the body is responding to disease
3. What correlates with an increased number of neutrophils?
A: bacterial infection
4. What correlates with an increased number of lymphocytes?
A: intracellular infections such as viruses
5. What correlates with IgM presence?
A: Recent exposure to the immunogen
6. What correlates with IgG presence?
A: Patient exposed to immunogen days to months ago
7. What is the purpose of serology?
A: To detect, identify and quantitate Ag in clinical samples, and to evaluate the Ig response
to infection.
8. What are the two methods of serology?
A: Immunoassays for Cell-Associated Ags and Immunoassays for Ig and soluble Ags
9. What are immunoassays for cell-associated Ags?
A: Immunofluorescence (IF), Enzyme Immunoassay (EIA), Flow Cytometry (FC)
10. What are immunoassays for Ig and soluble Ags?
A: Immunoprecipitation (IP), Enzyme-Linked Immunosorbent assay (ELISA),
Radioimmmunoassay (RIA), and agglutination
11. IF and EIA use what type of light to excite the fluorochromes?
A: UV light
12. What is the difference between direct and indirect IF/EIA?
A: Direct results from fluorochromes, bound directly to Ig, binding to Ags. Indirect results
from secondary Ig labeled with fluorochromes bind to Ig that is bound to Ags.
13. What excites fluorochromes in FC?
A: Laser
14. What does FC use to compare separate molecules detected?
A: dot plots
15. What method is used to sort cells into fluorescent and non-fluorescent?
A: Fluorescence Activated Cell Sorting (FACS)
16. What is FSC and what does it determine? What is SSC and what does it determine?
A: Forward scatter—size of cells; Side scatter—density of cells
17. What strategies are used to analyze FC data?
A: Gating strategies
18. Describe the steps of gating in FC.
A:
 Isolate the population of cell of interest
o Draw a box (gate) around the desired cells
 Exclude unwanted cells (dead)
o Draw gate around desired cells (alive)
 Select for specialized cell (CD3+)
o Draw gate around desired specialized cell
 Examine specific cell population in the specialized cell sample
o Draw gate around each to look at specific cell population
19. What is used to bind to phospholipid membrane of apoptotic/dead cells in FC?
A: Aqua dye
20.
What cells represent the 42.4%? What cells represent the 24.1%?
A: CD8-CD3+; CD8+CD3+
21. Describe the process of immunoprecipitation.
A: Protein in solution in test tubeadd Ig against protein of interestIg binds to protein of
interestAdding a protein A or G binds to antibody making it
insolublecentrifugeremove supernatant (solution) and keep pellet
22. What is an ELISA?
A: It is a procedure used to detect Ags or Igs. Ags or Igs are attached to a solid surface
(plastic plates) and a test sample is added. An enzyme system is then attached to the Ag-Ig
complex for detection.
23. What does an indirect ELISA detect?
A: Antibodies
24. Describe the Indirect ELISA.
A: Coat plate with purified Agwash away unbound Agadd blocking agent to bind up free
siteswash away unbound blocking agentadd patient samplewash away unbound
Igadd enzyme conjugated Igs specific for Fc region of primary Igwash away unbound
enzyme-Ig complexadd substratecolor formationmeasure absorbance (concentration)
25. What does a direct ELISA detect?
A: Antigens
26. Describe the Direct ELISA.
A: Coat plate with purified Igwash away unbound Igadd blocking agent to bind up free
siteswash away unbound blocking agent add patient samplewash away unbound
AgAdd enzyme-conjugated Ig to make a “sandwich”wash away unbound enzymeIgadd substrateNegative controls omit unknown Ag (Positive), Positive controls use
known Ags
27. How does an indirect agglutination work?
A: It detects patient serum (Ig) against cell Ags attached to latex beads, or Igs may be
attached to beads to test for presence of Ag.