Immunology Final Exam EC HW

UNGRADED HW 19 What two features are common across many allergens? Explain why scientists believe these features potentially make molecules MORE likely to be allergenic.

-protease activity - molecules w/ this can potentially breach host cell barriers further impacting immune cells deep in tissues -PAMP association - molecules w/ this basically trigger the immune system once recognized

How long does B-cell maturation from an HSC to a mature B cell take?

1 to 2 weeks

Put the following events in the correct order demonstrating the events that occur after a virus has entered the respiratory tract or digestive tract.

1. virus binds to TLRs on epithelial cells 2. Interferon alpha is secreted 3. NK cells divide and differentiate 4. NK cells induce apoptosis of infected cells

Which of the following cell types is LEAST likely to be killed by a NK cell?

A bacterial cell

Which of the following cell types is LEAST likely to be killed by a NK cell?

A bacterial cell OTHER CHOICES A virus-infected cell; A fetal cell; A tumor cell

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.

Which of the following is a potential cause of chronic inflammation?

All of the answers are correct.: Infectious agents; Tissue damage; Obesity; Intestinal commensal microbiota components

What happens to autoreactive cells that escape the thymus?

All of the answers are correct: They require TCR ligation and costimulation to be activated. They attack self-tissues. They negatively regulate other autoreactive cells. They can be rendered anergic.

Which of the following complement fixation pathways can be initiated by a soluble C3 convertase?

Alternative

UNGRADED HW 19 Regarding Myasthenia Gravis, which of the following statements is true?

An antagonistic IgG antibody is binding to the ACh receptor blocking it from stimulation, leading to paralysis

Which of the following is NOT entirely a response of the innate immune system? a. Antibody-mediated complement activation b. Protection from infection by the skin c. Microbial cell lysis by defensin d. Phagocytosis by macrophages e. low pH in stomach

Antibody-mediated complement activation OTHER CHOICES: Protection from infection by the skin, Microbial cell lysis by defensin, Phagocytosis by macrophages, low pH in stomach

Which of the following constitutes the critical survival cytokine for B cells in the secondary lymphoid tissue cortex?

BAFF

Why are many opsonins multimeric?

Because they bind repeating structures on pathogen surfaces

All blood cells in an adult human can trace their ancestry to which compartment within the body?

Bone Marrow

Deficiency in RAG1 and/or RAG2 can affect the proper development of which of the following cell types, resulting in decreased numbers of circulating cells of those types?

Both B and T cells

Which of the following is required for T-cell activation?

Both antigen-specific TCR binding to MHC peptide and interaction with CD80, CD86, or ICOS-L are correct.

Which of the following can be directly activated as a soluble protein in the microenvironment surrounding a pathogenic cell?

C3

Of the molecules listed, which can be considered the key molecule in complement pathways?

C5 convertase

Which of the following is the MOST potent anaphylatoxin produced during the complement cascade?

C5a

What is currently the BEST explanation for what determines whether a T cell develops into a CD8+ T cell or a CD4+ T cell?

CD4 or CD8 expression is determined by the strength and duration of the TCR/MHC interaction.

Activated TH cells signal to B cells to initiate their activation program via which of the following?

CD40L on the T cell to CD40 on the B cell

Activated Th cells signal to B cells to initiate their activation program via which of the following?

CD40L on the T cell to CD40 on the B cell

Match the molecule with the region of the cell it is used to label: proteins in the cytosol

CFSE

Which molecule is MOST closely associated with inhibitory responses to antigen?

CTLA-4

Match the number with the correct description:

Cell A: dendritic cell Cell B: activated T cell Molecule 2: CD28 Molecule 4: CRACC

Which of the following represents the EARLIEST stage in T-cell development?

DN

Name that cell. I am a small, nonproliferating cell found within the thymic cortex and contain CD4 and CD8 on my cell surface.

DP thymocyte

Which of the following would you predict to result from a mutation in TLR4 that prevents binding to LPS?

Decreased susceptibility to septic shock

UNGRADED HW 19 Which of the following BEST describes the difference(s) between types II and III hypersensitivity reactions?

Direct recognition of cell-surface antigens by antibodies in type II reactions versus deposition of improperly cleared antibody-antigen complexes in type III reactions

Match the technique with the correct description: performed on liquid samples

ELISA

Match the technique with the correct description: y-axis label (ng/ml)

ELISA

Match the technique with the correct description: uses antibodies to detect specific molecules

ELISA and IHC

Based on your knowledge of MHC I and II, predict which cell type would be MOST likely not to express detectable MHC I.

Erythrocytes

Match the region of the antibody with its correct function: if an antibody was attached to a virus, this region would be specifically binding to the virus

Fab

Match the region of the antibody with its correct function: this region contains the variable regions of the heavy and light chains

Fab

Match the region of the antibody with its correct function: if an opsonizing antibody was attached to a virus, this region could bind to receptors on a phagocytic cells and then signal for the virus/antibody complex to be phagocytosed

Fc

Match the region of the antibody with its correct function: this region contains the constant region of the heavy chain

Fc

Match the region of the antibody with its correct function: this region determines the isotype of the antibody

Fc

Match the region of the antibody with its correct function: this region is always different between IgG and IgE

Fc

Which Fc-receptor is responsible for triggering the release of histamine, proteases, and other inflammatory signals from IgE?

Fcε receptor

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? a. Histamine is released from cytoplasmic granules, recruiting macrophages to the site of infection. b. Fas-FasL signaling pathway is activated, triggering apoptosis. c. APC presentation occurs to both TC and TH cells. d. Antigen presented with MHC class I is recognized by CTLs e. Perforin and granzymes are released, triggering apoptosis of infected cell.

Histamine is released from cytoplasmic granules, recruiting macrophages to the site of infection. OTHER CHOICES Fas-FasL signaling pathway is activated, triggering apoptosis.; APC presentation occurs to both TC and TH cells.; Antigen presented with MHC class I is recognized by CTLs.; Perforin and granzymes are released, triggering apoptosis of infected cell.

This picture represents general components of cell signaling pathways associated with transmembrane receptors. Based on what you learned about CRACC, match the proteins/regions below with the correct description.

If Box 1 is pointing to the CRACC molecule what is the name of the regions represented by the yellow bars? ITSM motifs If arrow 1 is pointing to CRACC the protein that arrow 2 is pointing to represents: EAT-2 The regions represented by the red star in protein 2 is: SH2 Domain The enzyme SHIP would most likely inhibit the process indicated by: Box 4

UNGRADED HW 19 A person who is atopic is more likely to have high levels of:

IgE

Which type of antibody is MOST effective against the largest variety of pathogens?

IgG

Which class of antibodies is the FIRST to be produced during the primary immune response?

IgM

Which of the following immunoglobulin isotypes is the MOST efficient at initiating a complement fixation cascade?

IgM

Why is IgM the class of antibody able to form large polymers?

IgM has low affinity and benefits from having a large number of binding sites.

Considering the effects of EEP reported in the research article, which of the following would be the LEAST LIKELY y-axis label for this graph?

IkB bound to NFkB

Match the technique with the correct description: performed on tissue biopsies

Immunohistochemistry (IHC)

Match the technique with the correct description: y-axis label (% stained tissue)

Immunohistochemistry (IHC)

Where would you MOST likely find a TLR that recognizes RNA?

In the endosome/lysosome

Which of the following statements BEST differentiates innate and adaptive immune responses?

Innate responses are stronger during the primary and less important during the secondary response, whereas adaptive responses are less robust during primary responses and stronger during secondary responses.

What defines an exogenous antigen?

It is generated outside of the cell then taken into the cell by endocytosis.

What defines an endogenous antigen?

It is generated within the cell.

If a host cell has the ligand for _________, then the host cell is LESS LIKELY to be killed by a NK cell.

KIR2DL1

The TCRs on the surface of a T cell, which are all identical (usually), determine the antigen specificity of an individual T cell. Thus, to detect antigen-specific T cells, you need a molecule that will bind to the TCR. To detect an influenza specific CD8+ T cell, you would therefore need:

MHC I molecules containing influenza peptides

CD4+ T cells recognize

MHC class II peptides.

Which of the following adaptor proteins activate the NF-κB pathway?

MyD88

Which lineage of immune cells constitutes the first line of defense against an infection?

Myeloid

_____ describes the recruitment of phagocytic cells by the Fab portion of an antibody.

Opsonization

Match the technique with what is being assessed. used to determine if a gene is present in a chromosome

PCR

Match the molecule with the region of the cell it is used to label: plasma membrane

PKH67 dye

V-DJ recombination occurs during which phase of a B cell's development?

Pro-B cell

Match the molecule with the region of the cell it is used to label: DNA

Propidium Iodide

How does allelic exclusion prevent multiple heavy-chain rearrangements from occurring in pre-B cells?

RAG1 and RAG2 are downregulated, and TdT activity is lost so that no additional heavy-chain rearrangements may take place.

What introduces single-strand break between V(D)J coding sequence and heptamer RSS?

RAG1/2

What does the RAG 1/2 enzyme complex bind to at the start of the V(D)J recombination process?

RSS

Match the technique with what is being assessed. used to determine if a gene is being transcribed

RT-PCR

Which of the following cell types would be LEAST likely to express MHC class II?

T cells

Of the cells listed below, which one represents the MOST developed B cell?

T2 B cells

With regard to the type of B-cell response generated, protein antigens typically provoke which of the following responses?

TD

Fc-receptor molecules tend to have short cytoplasmic tails. How does this influence signaling events within the Fc-receptor cell?

The Fc-receptor is dependent upon a coreceptor (e.g., ITAM or ITIM) that will trigger signaling events within the cell.

The human MHC locus is one of the most polymorphic regions of the genome. What does this mean?

There are many different alleles of these genes.

Follicular helper T cells are a recent discovery in the helper T-cell lineage. What is the primary role of TFH cells?

To help B-cell development in germinal centers

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 neutralize toxins and pathogens

What is the function of a memory T cell?

To provide an almost immediate response upon subsequent exposure to a specific pathogen

UNGRADED HW 19 Hypersensitivity reactions to cell surface antigens via IgG or IgM are classified as which type?

Type II hypersensitivity

In heavy chain genes, what are the gene segments?

V, D, J

What types of cells are good targets for natural killer cells and why?

Virally infected cells because they have low levels of class I MHC

Match the technique with what is being assessed. used to determine if a protein is phosphorylated

Western Blot

An electrophoretic mobility shift assay determines if:

a protein is able to bind to a specific nucleotide sequence

Which of the following correctly describes an ELISA? All correct answers must be selected to receive full credit.

a standard curve can be used to determine concentrations of a molecule in a sample, providing quantitative data; uses antibodies with enzymes attached; uses antibodies to bind to a specific target

In negative selection, cells that receive _____ signal through their antigen receptors die.

a strong

What is the effector molecule of humoral immunity?

antibodies

Virally infected host cells are tagged with antigen-antibody complexes. These complexes recruit NK cells that trigger apoptosis in the infected host cell. This is an example of

antibody-dependent cell-mediated cytotoxicity

Which most accurately represents the general order of the steps to antigen presentation?

antigen acquisition, antigen breakdown into peptides, encounter of peptides with MHC molecules, binding of peptides to MHC molecules, and display of the peptide-loaded MHC molecules on the cell surface

MHC molecules

are recognized by T cells.

BALF would most likely be collected if you were studying:

asthma

In cytokine activated cells, STAT proteins are more likely to: (choose the two correct answers)

be bound to DNA, form dimers

Which of the following would NOT be included when examining a person's exposome? a. drinking lead contaminated water b. living at a high altitude c. being born with a p53 mutation d. working in a coal mine

being born with a p53 mutation

The CTLA-4 expressed by Tregs is used to:

bind to co-stimulatory molecules on dendritic cells and block co-stimulation of naive T cells

Regions of TCRs and BCRs that are particularly variable in their amino acid sequences are known for

binding to antigen.

B lymphocytes are made in the

bone marrow

Committed lymphocyte progenitors originate in the

bone marrow

ELISPOT assays

both involve the use of "capture" antibodies and are used to detect individual cells.

Peptide-binding diversity is increased by

both multiple MHC alleles in the population and multiple homologous MHC genes in the genome.

How do natural killer cells kill their targets?

by inducing apoptosis

IL-6 and TNF-alpha are BOTH

can cause the amount of interstitial fluid to increase in an infected tissue

In the research described in the article by Sittisart et al., which of the following serves as a positive control?

cells treated with LPS

Lysis of a pathogen by MAC formation is an example of

complement fixation

All of the following are functions of TH1 cells EXCEPT a. involved with delayed type hypersensitivity reactions b. protect against intracellular pathogens. c. contribute to autoimmunity. d. enhance APC activity e. enhance TC activity.

contribute to autoimmunity. OTHER CHOICES involved with delayed type hypersensitivity reactions.; protect against intracellular pathogens.; enhance APC activity.; enhance TC activity.

UNGRAGED HW 19 Tregs and dendritic cells that interact with Tregs both have active indoleamine-2,3-dioxygenase (IDO). IDO is an important enzyme since it:

converts an essential amino acid into an alternative metabolite

CD8+ T cells exposed to MHC class I peptides are

cytotoxic T cells.

TH17 cells are involved with all of the following EXCEPT a. autoimmunity b. inflammatory response c. protection against bacterial infections d. delayed-type hypersensitivity. e. protection against fungal infections.

delayed-type hypersensitivity. OTHER CHOICES autoimmunity.; inflammatory response.; protection against bacterial infections.; protection against fungal infections.

Hematopoiesis produces

erythroid, lymphoid and myeloid lineage cells

In order to measure regulatory T cells, FoxP3+ cells are often measured. FoxP3 functions by:

increasing transcription of anti-inflammatory genes

NK cells are more likely to be activated by a cell line that:

lacks MHC class I molecules

The research described in the article by Melissa Bates et al., was performed using:

mice that spontaneously develop Lupus-like symptoms over time

_____ describes the action of antibodies whereby antibodies bind to a pathogen and prevent the pathogen from interacting with cell receptors.

neutralization

In flow cytometry, in addition to fluorescent markers, forward (FSC) and side (SSC) scatter are measured, and

none of the answers are correct: forward scatter is a reflection of the internal complexity of the cell.; side scatter is a measure of the amount of DNA in the cell.; forward scatter is a measure of the amount of DNA in the cell.; side scatter is a reflection of the size of the cell.

UNGRAGED HW 19 The hygiene hypothesis is a possible explanation for:

prevalence of allergies in developed countries

A positive feedback loop would be useful in all of these scenarios EXCEPT: a. in amplifying the amount of a cytokine that employs a positive feedback loop b. preventing an overreaction to a stimulus. c. early in an immune response d. It would be useful in all of these scenarios e. in increasing the strength of a response

preventing an overreaction to a stimulus. OTHER CHOICES: in amplifying the amount of a cytokine that employs a positive feedback loop.; early in an immune response.; in increasing the strength of a response.

CFSE is used to measure _________________of cells. This process is occurring ____________in cells as the levels of CFSE decrease.

proliferation...........more

If an inflammasome has formed in a cell, the cell is most likely:

secreting interleukin 1 (IL-1)

Where do developing B cells complete their maturation through the T1 and T2 stages?

spleen

Licensing on an NK cell refers to

testing an NK cell to ensure that it will not target healthy host cells.

The DIFFERENCE between NK cells and T lymphocytes is: (must select the two correct answers to receive full credit)

the amount of time it takes for their level to increase in a patient with a viral infection AND their receptors that bind to MHC I molecules

An example of ectopic lymphoid tissue would be follicles located in:

the kidneys

The y-axis label of ELISA data is often "O.D.". What does this refer to?

the light emitted from the enzyme/substrate reaction

Most people are exposed to DHA when:

they eat fish

NK receptors are encoded in the germ line and are described by all of these EXCEPT: a. they do not undergo rearrangement b. they are invariant c. they recognize a severely limited set of ligands. d. they recognize likely pathogen.

they recognize likely pathogen. OTHER CHOICES: they do not undergo rearrangement.; they are invariant.; they recognize a severely limited set of ligands.

Naïve CD4+ and CD8+ T-cells leave the _____ and enter circulation.

thymus

The role of cell-mediated immunity is

to find and eliminate cells infected with intracellular pathogens.

Antibodies consist of

two identical heavy chains and two identical light chains

The first immunoglobulin isotype produced during the course of a primary immune response contains which of the following heavy chains?

μ