Immunology (BIO 430)-EXAM 4
What are the two different immune responses to vaccines depending on the type of antigen?
-T cell dependent responses to protein antigens -T cell independent responses to carbohydrates
What are the two main types of B cell responses, and the differences between them?
-T dependent (TD) response, depends on recognition of proteins and requires participation of CD4+ T helper cells -T independent (TI) response, activation of the B cell without a T helper cell
What are the three cell types needed for Tc activation?
-T helper cell -licensed dendritic cell -CTL precursor (Tc cell)
What are the three mechanisms peripheral tolerance uses?
-anergy -apoptosis -regulatory cells
What are the three types of memory cells we covered?
-central memory T cells (Tcm) -effector memory T cells (Tem) -tissue resident T cells (Trm)
What are the two branches of tolerance?
-central tolerance -peripheral tolerance
How does sequential activation of a Tc happen?
-first a DC interacts with a pathogen throught TLR and interacts with a helper T cell -Next the licensed DC interacts then with a TC and activates it
How does simultaneous activation of a Tc happen?
-first the precursor CTL engages dendritic cell that is associated with T helper cell and simultaneously is activated
What is the phenotype of activated B cells? (what does it increase/decrease expression of)
-increases MHC class II expression -increases CD80/CD86 expression -expression of CD40 -increased CCR7
What is active immunization? and describe it
-intentional triggering of the adaptive immune system to generate protection and memory against second infection -long lived and does generate memory
What are the six types of vaccines we discussed?
-live, attenuated vaccines -killed, inactivated vaccines -subunit vaccines -recombinant vaccines -conjugated vaccines -DNA and RNA vaccines
How does peripheral tolerance limit self attack?
-makes self reactive lymphocytes nonresponsive -actively generates inhibiting lymphocytes
What happens after B cells interact with T cells?
-migrate into borders of T cell areas of lymph nodes or -enter B cell follicles of lymph nodes and spleen
What are the two main techniques to induce protective immunity?
-passive immunization -active immunization
What are the three stages of B cell development?
-pre pro cell stage -pro cell stage -pre cell stage
Why are CD4+ T helper cells so important?
-production of cytokines like IL-2, IFN-gamma -expression of CD40 ligand (CD40L)
What are the two possible ways for activation of a naive Tc?
-sequential activation -simultaneous activation
What are the three signals of activation of a naive Tc?
-signal 1: TCR binds peptide presented by APC on MHC class I -signal 2: costimulatory signal transmitted by CD28-B7 interaction between T cell and APC -signal 3: provided by IL-2, inducing proliferation and differentiation into CTL form
What is passive immunization? and describe it
-the delivery of preformed antibodies (antisera) -it is a short lived immunization that does not generate memory
Central tolerance... -limits development of autoreactive T cells -limits development of autoreactive B cells -Does not affect the risks for autoimmune diseases -1 and 2 are correct -1 and 3 are correct
1 and 2 are correct
What are the two stages of cytotoxic T lymphocytes (CTL) activation?
1) activation of a naive Tc (precursor CTL) to CTL in secondary lymphoid organ 2) effector CTL function in the periphery
What is the sequence of events involved in delivering antigens by APCs?
1) antigen uptake 2) antigen processing 3) APC migration to lymph nodes 4) antigen presentation to naive T cell
What are the six antibody mediated effector functions?
1) neutralization 2) agglutination 3) opsonization 4) complement activation 5) antibody dependent cell mediated cytotoxicity (ADDC) 6) antibody dependent degranulation and mediator release
What are the three key processes that occur in germinal centers?
1) somatic hypermutation (SHM/affinity selection) 2) class switch recombination (CSR) 3) generation of memory B cells
How long does B-cell maturation from an HSC to a mature B cell take? -1-2 hours -1-2 days -1-2 weeks -1-2 months -1-2 years
1-2 weeks
Which of the following do you expect would be actively functioning in a B cell that had migrated to a germinal center as the result of the interactions with a T cell? -Artemis -TdT -RAG1 -AID
AID
The Fas ligand (FASL) represents a key-signaling pathway among cell-mediated effector cells. What is the function of the Fas-FasL signaling pathway? -Activation of the Fas-FasL signaling pathway triggers apoptosis. -Binding of Fas to FasL induces phagocytosis by dendritic cells. -Expression of Fas occurs only on naïve B cells. -FAS-FASL binding recruits Th cells -TNF-alpha is released by NKT cells triggering histamine release in infected target cells.
Activation of the Fas-FasL signaling pathway triggers apoptosis.
Tolerance is promoted by... -induction of anergy. -induction of apoptosis. -regulation of activity of cells. -All of the above.
All of the above.
After endocytosing its BCR cognate antigen, B cells -upregulate CD80 -upregulate CD86 -upregulate CD40 -All of the answers are correct -None of the answers are correct
All of the answers are correct
After production, naïve lymphocytes travel through the blood and might end at the... -spleen. -lymph nodes. -barrier organs. -All of the answers are correct. -None of the answers are correct.
All of the answers are correct
Autoimmune diseases -may involve a failure of central tolerance. -may involve a failure of peripheral tolerance. -lead to tissue destruction. -All of the answers are correct. -None of the answers are correct.
All of the answers are correct
During and due to activation, naïve CD4+ T cells -interact with antigen-presenting cells. -begin to proliferate -move to interact with B cells -All of the answers are correct.
All of the answers are correct
Reticular networks in the lymph nodes -are made of fibroblasts. -guide T-cell movements. -guide B-cell movements. -regulate lymphocyte direction. -All of the answers are correct.
All of the answers are correct
Myasthenia gravis is an autoimmune disease that -is triggered by antibodies. -targets the neuromuscular junction. -may lead to destruction of muscle cells by complement system -All of the answers are correct. -None of the answers are correct.
All of the answers are correct.
Which of the following is the CORRECT sequence of events? -Antigen uptake > antigen processing > APC migration to lymph nodes > antigen presentation -APC migration to lymph nodes > antigen uptake > antigen processing > antigen presentation -APC migration to lymph nodes > antigen presentation > antigen uptake > antigen processing -Antigen uptake > antigen processing > antigen presentation > APC migration to lymph nodes -APC migration to lymph nodes > antigen uptake > antigen processing > antigen presentation
Antigen uptake > antigen processing > APC migration to lymph nodes > antigen presentation
In germinal centers with is in the light zone?
B cells interspersed with a network of follicular dendritic cells (FDCs), (primary site of plasma and memory cell differentiation)
What is receptor editing?
B cells that are too self reactive it can go through rearrangement again.
What is the specific marker for the B cell lineage?
B220 (CD45R)
Which of the following antigen types could be characterized as TI antigens? -Soluble proteins -Bacterial cell wall components -Bacterial cell wall components and polymers such as capsular polysaccharides -All of the above are correct
Bacterial cell wall components and polymers such as capsular polysaccharides
Examples of cytotoxic effector cells include all of the following EXCEPT -Basophils -Neutrophils -macrophages -CTL -NK cells
Basophils
Peripheral tolerance... -Is caused by TCR-MHC+peptide interaction without costimulation. -Leads to anergy. -Both 1 and 2
Both 1 and 2
What chemokines attract naive T cells in the lymph nodes?
CCL21 and CCL19
Once an antigen is bound what do B cells up regulate to stimulate them to interact with T helper cells?
CCR7
Which of the following molecules expressed in activated T helper (Th) cells signal to B cells to initiate their activation program? -CD40L on the T cell to CD40 on the B cell -CD40 on the T cell to CD40L on the B cell -FasL on the T cell to Fas on the B cell -Fas on the T cell to FasL on the B cell -Notch ligand on the B cell to notch-1 on the T cell
CD40L on the T cell to CD40 on the B cell
What is the the other name for cytotoxic T lymphocytes?
CD8+ T cells
Cell-mediated effector cells include: -CTL and NKT cells. -Plasma cells and dendritic cells. -CTL and NK cells. -CTL, NKT cells, and NK cells. -CTL and memory Th cells
CTL, NKT cells, and NK cells.
Which molecule is MOST closely associated with inhibitory responses to antigen? -TCR -NHC class I -CD80 or CD86 -CTLA-4
CTLA-4
B cells follow which of the following chemotactic signals to migrate to the cortical regions of secondary lymphoid tissue? -CCL19 -CXCL13 -CCL21 -Both 1 and 3 -None of the above
CXCL13
What chemokine attracts naive B cells in lymph nodes?
CXCL13
Cell mediated immunity includes: -antibodies. -plasma cells. -Cytolytic T lymphocytes (CTL) B cells
Cytolytic T lymphocytes (CTL)
We have not successfully developed an effective vaccine against one of these diseases yet... which one? -Diphtheria -Measles -HIV -Poliomyelitis -Tetanus
HIV
CTLs mediate a powerful and lethal immune response to infected host cells. Which of the following steps is NOT involved with CTL activation and function? -Antigen presented with MHC class I is recognized by CTLs. -APC presentation occurs to both precursor CTL and Th cells -Fas-FasL signaling pathway is activated triggering apoptosis. -Histamine is released from cytoplasmic granules recruiting macrophages to the site of infection -Perforin and granzymes are released triggering apoptosis of infected cell.
Histamine is released from cytoplasmic granules recruiting macrophages to the site of infection
Mature naïve B cells express high levels of ____ on their cell surfaces. -IgA -IgD -IgE -IgG -IgM
IgD
Which class of antibodies is good at fixing complement? -IgA -IgD -IgE -IgG
IgG
Which maternal antibody is protective against diseases such as diphtheria, tetanus, streptococcal infections, and measles when transferred to fetus? -IgE -IgG -IgD -IgM -All classes of immunoglobulins
IgG
What is always the first antibody to be produced in a primary response?
IgM
Which class of antibodies is the FIRST to be produced during the primary immune response? -IgA -IgD -IgE -IgG -IgM
IgM
Why is IgM the class of antibody able to agglutinate pathogens? -IgM is the strongest binding antibody class. -IgM is considered the most important type of antibody. -IgM has low affinity, but it benefits from having a large number of binding sites. -IgM is used exclusively against parasites. -IgM requires form polymers traveling through the body.
IgM has low affinity, but it benefits from having a large number of binding sites.
The function of somatic hypermutation (SHM) is BEST described by which of the following statements -Increasing junctional diversity in IgH and IgL V regions -Increasing the affinity of immunoglobulins for their antigen -Irreversibly changing the isotype of immunoglobulin -Promoting alternative splicing of an immunoglobulin heavy chain transcript to produce different isotypes on the B-cell surface -None of the answers are correct.
Increasing the affinity of immunoglobulins for their antigen
Lymphocytes exit the blood and enter the lymph nodes by extravasating at the high-endothelial venules (HEVs) interacting with ____________ expressed on the endothelial cells. -Ligands for L-selectin -L-selecting -T cell receptors -CD4 or CD8 coreceptors -All of the answers are required
Ligands for L-selectin
Immature B cells in the bone marrow that are found to bear self-antigen reactive BCRs undergo which of the following? -Clonal expansion -Light chain receptor editing -positive selection -All of the answers are correct.
Light chain receptor editing
_______ describes the action of antibodies whereby antibodies bind to a pathogen and prevent the pathogen from interacting with cell receptors. -Antibody-dependent cell-mediated cytotoxicity -Antigen presentation -Complement fixation -Neutralization -Opsonization
Neutralization
One if these statements about toxoid vaccines is NOT true. Toxoid vaccines... -Can be made from toxin that has been inactivated with heat -Can be made from toxin that has been inactivated with a chemical treatment. -Can be used in conjugated vaccines -Normally don't require intermittent boosters -All of them are true
Normally don't require intermittent boosters
_______ describes the recruitment of phagocytic cells by the Fab portion of an antibody, and phagocytosis of the pathogen. -Antibody-dependent cell-mediated cytotoxicity -Antigen presentation -Complement fixation -Neutralization -Opsonization
Opsonization
Which of the following is recognized by the innate immune system and triggers an immune response that will produce antiviral cytokines and trigger effector molecules? -Complement system -IgA -IL-2 -TNF-alpha -Pathogen associated molecular pattern (PAMP)
Pathogen associated molecular pattern (PAMP)
At what stage of development does a B cell begin to express a pre-B-cell receptor? -Pre-pro B cell -Early pro-B cell -Late pro-B cell -Pre-B cell -Immature B cell
Pre-B cell
At what location are naïve CD8+ T cells activated to become CTLs? -Blood stream -Bone marrow -Secondary lymphoid organs -Thymus
Secondary lymphoid organs
B cells have been shown to need two signals for activation. Absent T-cell help, they will NOT activate because -T cells provide signal 1 through the B-cell receptor. -T cells provide signal 2 through IL-2. -T cells activate B cells through CD40 signaling. -B cells will still activate because of dendritic cells.
T cells activate B cells through CD40 signaling
Absent T-cell help, they will not activate B cells for their differentiation into plasma cells because: -T cells provide signal 1 through the B-cell receptor. -T cells provide signal 2 through the B-cell receptor. -T cells activate B cells indirectly by activating follicular dendritic cells. -Correct Answer T cells activate B cells through CD40/CD40L signaling. -Actually, they will still activate because of dendritic cells.
T cells activate B cells through CD40/CD40L signaling
Protein antigens typically provoke which of the following responses? -T-independent-1 -T-independent-2 -T-Dependent -None of the above -Both 1 and 2
T-Dependent
Of the cells listed below, which one represents the MOST developed B cell? -Pre-pro-B cell -Pro-B cell -Pre-B cell -T1 B cells -T2 B cells
T2 B cells
What would happen if a person who is undergoing chemotherapy were given a live virus vaccine against polio? -The cancer patient would likely develop a strong immune response to the vaccine because a live viral antigen was used. -The cancer patient would likely develop polio because the immune system is compromised and would not be able to fight off the live virus. -The chemotherapy the cancer patient is receiving would inactivate the vaccine by killing the live polio virus. -There would be no effect, as the cancer patient does not produce a high number of immune cells for the polio virus to interact with.
The cancer patient would likely develop polio because the immune system is compromised and would not be able to fight off the live virus
Which of the following statements about NKT cells is TRUE? -They kill target cells by apoptosis. -NKT cells rely on opsonization to cause apoptosis in an infected host cell. -NKT cells express all of the T cell lineage characteristics. -The TCR on NKT cells recognizes antigens presented with MHC class I and class II molecules
They kill target cells by apoptosis
IgA is typically found as a dimer in high levels of secretions such as milk, tears, and saliva. What is the primary function of IgA in secretions? -To alert plasma cells of an invading pathogen -To neutralize toxins and pathogens -To secrete nonspecific enzymes such as lysozyme -To stimulate the growth of normal microbiota (normal flora) species -To trigger apoptosis in infected mucosal cells
To neutralize toxins and pathogens
What is herd immunity? -A global vaccination day established by the World Health Organization to ensure every person on the planet is vaccinated against a particular pathogen. The last herd immunity day was in the early 1980s with smallpox. -A vaccination program started by progressive nations to prevent the spread of prion diseases such as Mad Cow (BSE). -Herd immunity refers to a special vaccination method whereby immunocompromised individuals are given vaccines made only of antibodies. -Receiving all government recommended vaccines in one day. This produces the strongest immune response possible but frequently leaves the person being vaccine experience malaise (generally feeling bad) and feverish. -Vaccinating the majority of a population to protect immunocompromised individuals from a particular pathogen.
Vaccinating the majority of a population to protect immunocompromised individuals from a particular pathogen
What is anergy?
a state of non-responsiveness to further stimuli by cells
Are vaccines active immunization or passive immunization?
active immunization
What is complement activation?
antibodies bind with complement system components in surface of pathogen to a exacerbate inflammation, use membrane attack complexes, or opsonization of pathogens
Activation of naïve B cells is a two-step process, during which -antigen triggers B-cell production of CCR7, which leads it to interact with T cells. -antigen triggers T-cell production of IL-2, which recruits B cells. -T-cell help stimulates B cells to produce CCR7, then divide. -None of the answers are correct.
antigen triggers B-cell production of CCR7, which leads it to interact with T cells
What does neutralization of a pathogen do?
blocks access of the pathogen to tissues
B lymphocytes are made in the: -blood stream. -bone marrow. -liver. -thymus. -Peyer's patches.
bone marrow
What is autoimmunity?
break down of self tolerance caused by the failure of tolerance processes
One if these statements about killed vaccines is NOT true. These vaccines... -are often stable/easy to store and transport -often require booster shots -can revert to pathogenic forms -are made by inactivating the whole pathogen by heat or by chemicals -All of them are true
can revert to pathogenic forms
What do naive lymphocytes enter the spleen through?
capillaries from central arteriole
How do viruses typically enter host cells?
cell surface receptor
Lysis of a pathogen by MAC formation is the result of: -antibody-dependent cell-mediated cytotoxicity. -antigen presentation. -complement fixation. -neutralization. -opsonization.
complement fixation.
How are conjugated (multivalent) vaccines made?
conjugating a carbohydrate to a protein
How does the interactions between CD4+ T helper cells, dendritic cells, and CD8+ T cells occur?
cross presentation (cross presentation allows dendritic cells to acquire antigens from non APCs and present them on both types of MHC molecules)
What is antibody dependent cell mediated degranulation?
degranulation of granulocytes by antibodies
What are licensed dendritic cells?
dendritic cells that has upregulated co-stimulatory molecules to help precursor CTLs to become CTLs
In germinal centers what is in the dark zone?
densely packed with proliferating B cells (site of somatic hypermutation)
What is clonal deletion?
destruction of strongly autoreactive B cells by apoptosis
What is opsonization?
enhancement of the process of engulfing pathogens by phagocytic cells
What is extravasation?
exit of lymphocytes from the blood stream
What cell type are lymphocytes derived from?
hematopoietic stem cell (HSC)
What do naive lymphocytes enter the lymph nodes through?
high endothelial venules
What is herd immunity?
immunity of the population as a whole that is created by the majority of the population being vaccinated
What is failure of the immune system?
improper regulation that allows the immune system to either attack something it shouldn't or fail to attack something it should
Where do B cells encounter antigens (Ag)?
in the lymph nodes and spleen
What are toxoids?
inactivated toxins
How are inactivated/killed vaccines made?
inactivating the whole pathogen by heat or by chemicals
What type of immunity controls most fungal infections?
innate immunity
What is vaccination?
intentional exposure to forms of a pathogen that do not cause disease
What are the two major mechanisms that CTLs kill cells?
kill by promotion of apoptosis (two major mechanisms of this are 1) directional release of granule contents, 2) Fas-FasL interactions)
What is Bruton's Tyrosine Kinase (BTK)?
kinase that helps to complete the signaling of B cells to perform their function
How does central tolerance limit self attack?
limits development of autoreactive T and B cells (uses apoptosis to kill cells with high affinity for self)
How are subunit vaccines made?
made by isolating or making a specific components of a pathogen that can be given as a vaccine
How are toxoid vaccines made?
made from heating or chemically treating toxins to make the vaccine
What are naive lymphocytes constantly doing?
moving in search of antigens in the spleen, lymph nodes, and barrier organs
What is the difference between a naive and mature B cell?
naive B cells only have 1 B cell receptor (IgM) while mature B cells have 2 B cell receptors (IgM and Igd)
What is IgA's main function?
neutralizing toxins and pathogens
Can carbohydrates activate T cells?
no
Do B cells need to be presented with an antigen?
no
Will one single Fc bound to a single Fc receptor activate a signal?
no
Although our understanding of the kinetics of T-cell activation has changed over time, we now believe that -antigen exposure does not affect T-cell/APC interactions. -optimal proliferation of helper T cells requires only relatively brief (minutes) APC exposure. -optimal proliferation of helper T cells requires several hours of APC exposure. -dendritic cell activation does not affect T-cell activation.
optimal proliferation of helper T cells requires several hours of APC exposure
How are RNA/DNA vaccines made?
plasmids of the pathogen are taken and injected into the muscle
During B cell development Bruton's Tyrosine Kinase (BTK) is necessary for the positive selection at the... -pre pro B cell -early pro B cell -late pro B cell -pre B cell
pre B cell
What is tolerance?
prevention of an immune response against self structures
What does agglutination do?
prevents the binding of pathogens to cells by combining them together
What is immunization?
process of inducing a long lived state of protective immunity against a pathogen
As antigen is picked up in peripheral tissues by antigen-presenting cells, it is -processed for presentation to B cells. -processed for presentation to T cells. -taken in unprocessed form for presentation to T cells. -All of the answers are correct.
processed for presentation to T cells.
What is somatic hypermutation?
rearrangement of Ig genes resulting in various antibodies in which some have higher affinity
What is class switch recombination?
recombination of regions of DNA that create different immunoglobulins, allows immunoglobulins to go from IgG or IGD --> IgA, IgG, or IgE
What is antibody dependent cell mediated cytoxicity?
recruitment of natural killer cells by antibodies (need assistance by Fc receptors)
What is IgE best known for?
role in allergy and asthma, strong degranulation of eosinophils/basophils
Where is IgA usually found?
secretions
What is the signal number of CD40 binding to CD40L in B cell activation?
signal 2
Licensing on an NK cells refers to: -activation of an NK cell by MHC class II displayed peptide antigen. -expression of IFN-gamma and TNF-alpha by NK cells. -production of memory cells. -suppressing the activity of a self-recognizing NK cell. -testing an NK cell to ensure that it will not target healthy host cells.
testing an NK cell to ensure that it will not target healthy host cells.
Where in the lymph nodes do activated B and T cells interact?
the border between the follicle and paracortex
S1P1 receptor is upregulated by naïve T cells and B cells after 12-18 hours if they fail to encounter antigen in the lymph node. This means all of the following EXCEPT -the naïve cells have not been activated. -the naïve cells have not encountered antigen. -the naïve cells will exit the lymph node. -the naïve cells will start proliferating and differentiating.
the naïve cells will start proliferating and differentiating
S1P1 receptor is upregulated by naïve T cells and B cells after 12-18 hours if they fail to encounter antigen in the lymph node. This means all of the following EXCEPT -the naïve cells have not been activated. -the naïve cells have not encountered antigen. -the naïve cells will exit the lymph node. -the naïve cells will start proliferating and differentiating.
the naïve cells will start proliferating and differentiating.
Where does the final maturation and activation of B cells occur?
the periphery (mostly in the spleen)
What is the missing self model?
the recognition of self inhibits the ability to kill
The role of cell-mediated immunity is -to find cells infected with intracellular pathogens. -to find and eliminate cells infected with intracellular pathogens. -to present antigens to T helper cells -to produce memory B cells. -to secrete antibodies.
to find and eliminate cells infected with intracellular pathogens
What is the main function of B cells?
to produce and secrete antibodies specific against pathogens
To avoid returning to the lymph nodes, effector cells -up-regulate chemokine receptors to allow them to home in to site of infection. -down-regulate L-selectin, so they do not enter the high-endothelial venules (HEVs). -up-regulate chemokine receptors and downregulate L-selectin. -down-regulate both L-selectin and chemokine receptors.
up-regulate chemokine receptors and downregulate L-selectin
What happens if lymphocytes fail to find antigens in about 12-18 hours in the lymph nodes?
upregulation of sphingosine 1-phosphate receptor 1 (S1PR1), this allows the lymphocytes to leave the lymph nodes and return to circulation
Insulin-dependent diabetes (diabetes mellitus) -usually shows juvenile onset. -is more common in men that in women. -interferes with fat metabolism. -seems to be triggered by antibodies. -None of the answers are correct.
usually shows juvenile onset
Describe live, attenuated vaccines?
vaccine made of live, attenuated (weakened) organisms
Are T cells MHC restricted?
yes
Can carbohydrates active B cells?
yes
When the B cell exits the bone marrow does it have any immunoglobulins? if so which one/s
yes, only IgM
