Immunology- Random Study Questions

Tc cells differ from Th cells in that they carry the ______ receptor on their surface, and do not express CD4.

CD8

There are hundreds of millions of T cells and each has slightly different T cell ______. In practice, these _______ recognize almost anything that can serve as a protein antigen, and most non-peptide antigens.

receptors

________ ___ cells scan the surfaces of cells "looking" for the foreign antigens that they have been trained to detect.

Cytotoxic T

Action that can be achieved by different entities to result in the same function

redundant

Subset of T cells that act as regulators of the immune response. Play an important role in immunologic tolerance

regulatory T cells

Which cytokine downregulates the immune response? TNF-α IL-5 IL-1 IL-10

IL-10 This cytokine has anti-inflammatory effects.

Which of the following cytokine receptor sub units possesses no signaling capacity but acts as an affinity modulator? IL-2 receptor gamma chain IL-2 receptor alpha chain IL-17 receptor A IL-2 receptor beta chain

IL-2 receptor alpha chain

Which cytokine plays a major role in the induction of allergic responses? IL-3 IL-2 IL-1 IL-4

IL-4 This cytokine induces immunoglobulin class switching to IgE.

three basic types of antibody

IgG, IgA, IgM

is the first antibody made in response to infection and is the largest, is produced by the fetus and will bind complement

IgM

_________ ________ cells can detect self from non-self and when viral proteins are displayed; the infected cells are identified as non-self and destroyed.

Immune surveillance

In the thymus T cells interact with all _____ _______, presented in the surface of cells in the thymus.

self antigens

________ ____ is a cytokine that stimulates proliferation (clonal expansion) of the activated Tc cell (cytotoxic T lymphocyte).

Interleukin 2

The inside of cells

Intracellular space

Th cells also have a CD4 receptor on their surface. The CD4 receptor recognizes peptide antigens bound to _____ _______ ____ proteins

MHC Class II

Tc cells bear the surface protein CD8 on their surface. The CD8 receptor recognizes peptide antigens bound to _____ ______ __ proteins.

MHC class I

Ability of a host to react with a particular antigen only when components of that antigen, after processing,, are presented to T cells in combination with that individual's MHC

MHC restriction

_______, an anti-microbial peptide that bores a hole into the cell, is secreted by CTLs when they encounters an MHCI -foreign antigen complex..

Perforin

Professional APCs specialize in presenting antigen to ___ cells

T

These sequences are constitutively recombined to make different combinations of the amino acids that make up each ___ _______ _______. It is estimated that there are 100,000,000 different combinations possible.

T cell receptor

are coated in about 50,000 identical T cell receptors.

T cells

The TAP structure is formed of two proteins: ______ and ______

TAP-1 and TAP-2

Th1 cells - activate ___ cells

Tc

The primary function of _____ cells is to destroy cells infected by a pathogen.

Tc

eventually differentiate to become cytotoxic T cells (CTLs)

Tc cells

accept information from macrophages and train other lymphocytes

Th cells

is a soluble protein elaborated by T cells, and macrophages when these cells encounter infected cells.

Tnfα

Helpful tip

To help remember which molecules presents to ehich cells, the answer is always 8. That is, MHC II presents to CD4 cells (2 x 4 = 8) MHC I presents to CD 8 cells ( 1 x 8 = 8)

Why is Haemophilus influenzae type B rare in adults but sometimes acquired by children? a. Because T-independent responses are stunted in children b. because children lack cytotoxic T cells c. because children do not produce B cells d. because adults produce a capsule that simulates a response

a. Because T-independent responses are stunted in children

An adhesion molecule called _____ is expressed exclusively on activated dendritic cells and binds to _____ on naive T cells in the T-cell areas of secondary lymphoid tissue.

a. DC-SIGN; ICAM-3

Which of the following is not produced by TH1 cells in humans? (Select all correct answers)

a. IL-10, b. TGF-β

What class of antibody is able to cross the placenta from mother to developing fetus? a. IgG b. IgM c. IgE d. IgA

a. IgG

In the absence of a co-receptor (CD4 or CD8 for T helper cells or cytotoxic T cells, respectively), T cells require _____ specific peptide:MHC complexes on the antigen-presenting cell compared with interactions involving a co-receptor.

a. more

Dendritic cells take up, process or present antigen by which of the following routes? (Select all that apply)

a. receptor-mediated endocytosis of bacteria using the mannose receptor, b. macropinocytosis of soluble antigens, d. cross-presentation from the MHC class II pathway to the MHC class I pathway, e. cross-presentation from incoming infected dendritic cells to healthy resident dendritic cells in secondary lymphoid tissue

Factors thought to have an influence on the differentiation of CD4 T cells into either TH1 or TH2 include (select all that apply):

a. the cytokines made during the preceding innate immune response, b. the type of antigen-presenting cell interacting with the T cell, c. the cytokines made by the antigen-presenting cell interacting with the T cell, d. the number of specific peptide:MHC complexes presented by the antigen-presenting cell

All of the following are true of dendritic cells EXCEPT ________. a. they only process endogenous antigens b. they are found under the surface of the skin and mucous membranes c. they migrate to the lymph nodes after acquiring antigen d. they are involved in antigen presentation

a. they only process endogenous antigens

Cytokine or hormone that acts of the cell that produces or secreted it

autocrine effect

Interleukin-2 can stimulate proliferation in the T cells that secreted it. This property is known as a(an): paracrine effect. endocrine effect. autocrine effect. singleton effect.

autocrine effect This term means that the cytokine can have an effect on the very cell that produced it.

As T cells leave the bone marrow, they enter the

thymus

T cell mature in the: thymus spleen pancreas lymphatics

thymus

TH1 cytokines exert which of the following effects? (Select all that apply.)

b. B-cell differentiation, c. macrophage activation, d. production of opsonizing antibodies

_____ is a second messenger in the T-cell signaling pathway leading to the activation of NFAT.

c. Inositol triphosphate

Tuberculoid leprosy is characterized by a _____-type response where patients _____.

c. TH1; usually survive

T cells-----> _______ ___ _______

cytotoxic T lymphocytes

Which of the following is NOT used by cytotoxic T cells to kill cells infected with pathogenic microbes? a. perforin b. ganzymes c. CD95L d. lectins

d. lectins

State of development in the production of T cells in which the cells do no express neither CD4 nor CD8

double negative lymphocytes

In theory, each B cell reacts to a single _______

epitope

the blood and extracellular fluids

extracellular space

In theory, each receptor recognizes something different from all other T cell receptors. For any given antigen, there will be a range of T cell receptors (T cells) that will bind that antigen. Some will bind tightly (______ ______) and some will bind weakly (______ ______).

high affinity and low afffinty

State of unresponsiveness specific for a particular pathogen

immunological tolerance

A major function of Interleukin 2 (IL-2) is to: promote B-cell differentiation into plasma cells. induce proliferation of activated T cells. induce the acute phase response. suppress the immune response.

induce proliferation of activated T cells IL-2 stimulates the immune response by this mechanism.

The types of antibodies found in all different individuals in related species

isotype

IL-6 is made by: mast cells B cells T cells macrophages

macrophages

There are approximately _____ genes that encode for different T cell receptor proteins.

1000

Process in the development of thymocytes in which self-reactive thymocytes are deleted from the T-cell repertoire of the host

negative selection

Ability of an entity to have multiple functions

pleiotrophic

One cytokine can have multiple functions. This property is known as: pleiotropy. synergy. antagonism. redundancy.

pleiotrophy This property enables a single cytokine to affect multiple cell types.

Humoral Immunity: In this situation, the B cell acts as a _______ _______ ______ cell, activating a Th cell which simultaneously activates the B cell.

professional antigen presenting

MHC Class II proteins are found only on the surface of _________ ________ ______ _____

professional antigen presenting cells.

Th2 cells -- activate __ cells

B

eventually differentiate to produce antibody

B cells

receptor-mediated endocytosis of soluble antigen

B cells

Membrane-bound antibody

B-Cell Receptors

______ ________ are cell surface proteins that transmit apoptosis signals on binding death ligands, like Tnf-a and the Fas ligand.

Death receptors

________ is a protein on the surface of the cytotoxic T cell. It is a membrane bound variant of TNFa

Fas ligand

Which cytokine helps regulate the hematopoiesis of cells of the immune system? G-CSF TNF-α IFN-γ IL-5

G-CSF This cytokine is a colony-stimulating factor.

Which type of interferon do T cells produce? γ-interferon α-interferon β-interferon δ-interferon

Gamma interferon This interferon plays a major role in both innate and adaptive immune responses.

Naive lymphocytes homing to lymphoid tissue use _____ to bind to CD34 and GlyCAM-1 on high endothelial venules.

a. L-selectin

Peptide mediators that allows communication among different cells. cell signal by secreting a certain cytokine, that, in turn, binds to specific receptors on the surface of the cell receiving the signal

cytokines

CD8+ subset of T cells that can kill target cells infected by endogenous antigen such as a virus

cytotoxic T cells

8-8 Activated T cells express _____, which binds to B7 with twentyfold higher affinity for B7 than CD28 and results in _____ of T cell activity and proliferation.

d. CTLA4; suppression

IL-4 is induced in a CD4 TH2 cell under the direction of the transcription factor _____.

d. GATA-3

Which of the following is not produced by TH2 cells in humans? (Select the single BEST answer)

d. IFN-γ

T cells failing to encounter specific antigen leave lymph nodes via the _________.

e. efferent lymph

The area of contact between membranes of a T cell and an antigen-presenting cell where a clustering of protein-protein interactions occur is called a(n)

e. immunological synapse

When a cell makes a cytokine that affects a distant cell, the response is called: paracrine endocrine autocrine allocrine

endocrine

Action on cells far away from the cell that produced the signal

endocrine effect

A T cell receptor that is positive for CD4 and CD8 is: a helper and a killer T cell a double negative lymphocyte an immature or a tumor cell a T- suppressor cell

an immature or tumor cell

This is especially important when a virus is replicating in a cell.

antigen presentation

Antigen presentation to T cells is performed by: monocytes macrophages B cellls any of the above A and B only

any of the above

Tnfa is a cytokine that binds to specific receptors on the cell surface, initiating ________

apoptosis

If the T cell receptor (cell) binds tightly, a signal is released that induces ____________. In other words, those cells that recognize self are destroyed.

apoptosis (programmed cell death)

The co-stimulatory molecule _____ on professional antigen-presenting cells binds _____ on the surface of naive T cells.

b. B7; CD28

Which of the following is not produced by cytotoxic T cells?

b. CD40 ligand

CD8+ cells require interaction with: class I molecules class II molecules both class I and II gamma delta cells

class I molecules

Describe three distinct mechanisms by which naive CD8 T cells can be activated.

(i) Virus-infected dendritic cells provide adequate co-stimulation (via B7) and can activate CD8 T cells directly without the involvement of CD4 T cells. CD8 T cells receive signal 1 (MHC:T-cell receptor) and signal 2 (B7:CD28) and synthesize IL-2 and the high-affinity IL-2 receptor and proliferate and differentiate into cytotoxic T cells. (ii) The antigen-presenting cell is not a dendritic cell and does not express B7 until it is activated by an effector CD4 T cell. Once activated, the antigen-presenting cell upregulates B7, which is now available to provide the naive CD8 T cells with co-stimulation. (iii) The antigen-presenting cell expresses suboptimal levels of B7 sufficient for activation of a naive CD4 T cell, which then expresses IL-2. Meanwhile, a CD8 T cell with an engaged TCR:MHC complex on the same antigen-presenting cell has begun to express a high-affinity IL-2 receptor, but it does not express its own IL-2. The IL-2 is made by the CD4 T cells and captured by the adjacent CD8 T cell, which is thus activated.

In the thymus, T-cells are sorted to make sure they bind the appropriate cell surface molecules and to ensure that they do not recognize self peptides. Only ______% of immature T cells that enter the thymus exit as mature T cells capable of defending the host against intracellular infections.

1-2

Humoral Immunity: Two ways to activate a B cell to make antibody

1. Capping the receptors on a B-cell with a large repeating epitope (eg. complex carbohydrates); direct interaction between the antigen and the antibody 2. Single epitopes cannot cause capping; therefore the T helper cells bind and activate B cells

Humoral Response: Summary-Arming "loads the gun." Two events take place. ________ and _______

1. The B cell is converted to a plasma cell, which produces antibody. 2. There is a clonal expansion of that cell type.

There are _#_ types of antigen presentation

2

A. Explain the functional differences between immature and mature dendritic cells. B. Discuss why you think these functional changes should occur. C. Give an example of an immature and a mature dendritic cell.

A. Immature dendritic cells are very efficient at phagocytosis owing to expression of the receptor DEC 205. They also take up extracellular material indiscriminately by macropinocytosis. They have specialized pathways of antigen processing for extracellular antigens that can present these antigens on both MHC class I and class II molecules. They do not express co-stimulatory molecules. Immature dendritic cells migrate to nearby lymphoid tissue after antigen ingestion. Upon arrival in the lymphoid tissue, they differentiate into mature dendritic cells. These are non-phagocytic and express the co-stimulatory molecules B7.1 and B7.2. B. Immature dendritic cells need to be phagocytic because they are located in sites susceptible to infection. Expression of B7 in non-lymphoid tissue is not required because this is not where T cells circulate and sample peptide:MHC complexes. Once outside the infected tissue, mature dendritic cells no longer need to phagocytose material. They do, however, need to express B7 molecules, because without co-stimulation, T cells do not receive the necessary activation signal for differentiation into effector T cells. C. An example of an immature dendritic cell is the Langerhans cell of the skin, which matures into an interdigitating reticular cell in the lymph node.

Describe (A) the functions of macrophages in secondary lymphoid tissue, and (B) their location(s).

A. Macrophages are professional antigen-presenting cells that trap and break down pathogens delivered to the secondary lymphoid tissue from the lymph, and then present peptide:MHC complexes to naive T cells. They bear the mannose receptor, scavenger receptor, complement receptors, and several Toll-like receptors on their surface for the recognition of microbial components during innate immune responses. They also engulf and break down lymphocytes that die during the course of an immune response. B. Macrophages are distributed throughout the cortex and medulla of a secondary lymphoid organ and are not confined solely to T-rich areas, in contrast with dendritic cells.

A. Identify three types of professional antigen-presenting cell. B. How are they distributed in secondary lymphoid tissue? C. Which kinds of antigen do they present efficiently to T cells?

A. The three types of professional antigen-presenting cell are dendritic cells, macrophages, and B cells. B. Dendritic cells are found in T cell-rich areas of secondary lymphoid tissue; macrophages are distributed throughout the tissue; B cells are localized in lymphoid follicles. C. Dendritic cells present all types of antigen, but present viral antigens particularly efficiently. Macrophages present bacterial antigens well because they bear generalized receptors that can bind and internalize many different bacteria. B cells present peptides of soluble protein antigens, such as protein toxins, that they have internalized via their antigen receptors.

____ are very efficient at internalizing antigens, processing the antigen into peptide fragments and then displaying those peptides, bound to a MHC II molecule, on their membrane.

APCs

APCs express MHC class II molecules, which are presented to a helper T cell after an antigen peptide from a processed exogenous antigen has been associated with them. The helper T cell then recognizes the MHC class II/antigen complex presented by the APC. Why do these APCs also express MHC class I molecules?

All nucleated cells, including APCs express MHC I because MHC I molecules are involved in the presentation of endogenous antigens such as altered self-components or viral component expressed by virally infected cell. Because ALL nucleated cells can be potentiall infected or altered, and thus, need to be eliminated by cytotoxic T cells, APCs also express MHC I

Immunologic tolerance is a result of: positive selection of T cells capable of recognizing self-MHC in the thymus. negative selection of T cells capable of recognizing self-peptides in the thymus. clonal anergy of T cells capable of recognizing self-peptides in the peripheral lymphoid organs. All of the above

All of the above Immunologic tolerance prevents the body from attacking itself.

Cell-mediated response: IL-2 production---->

Autostimulation of Th and Tc cells specific for the antigen presented

___ cells are also considered professional antigen presenting cells

B

These cells are not completely differentiated (or "armed") to produce antibody

B cells

What surface markers are found on regulatory T cells? CD4 and CD25 CD8 and CD25 CD8 and CD16 CD4 and CD8

CD4 and CD25 One of the markers found on regulatory T cells is also found on T helper cells.

Give some examples of how cytokines can affect the function of other cytokines.

Cytokines can stimulate cells to release other cytokines and can down-regulate the production of other cytokines from cells. Certain cytokines can recruit cells at a particular site and induce those cell, in turn, to release their own cytokines locally. In addition, cytokines can modulate the expression of cytokine receptors on other cells, thus affecting the response of those cells to the cytokines for which they have receptors.

The etiological agent responsible for leprosy is Mycobacterium leprae, which survives and replicates within the vesicular system of macrophages. Explain the difference between tuberculoid leprosy and lepromatous leprosy in the context of T-cell differentiation and effector function.

Effective immune responses against intravesicular pathogens living in macrophages are mediated by TH1 cells rather than TH2 cells. In tuberculoid leprosy, the predominant effector T cells produced after infection are TH1 cells. These are effective in containing the infection, although they do not clear it completely. The disease is chronic and progresses slowly; the damage to skin and peripheral nerves is caused mainly by the inflammatory responses initiated by activated macrophages. In lepromatous leprosy, in contrast, the predominant T cells produced are TH2 cells. Humoral immunity is induced, which results in the production of antibodies that are ineffective against intracellular bacteria. As a result, M. leprae replicates unchecked, causing severe tissue destruction and eventually the death of the patient. Many factors influence the differentiation of CD4 T cells into TH1 or TH2 cells, including the cytokines produced by the antigen-presenting cells and leukocytes involved in the innate immune responses, the antigen concentration and peptide:MHC density, T-cell receptor affinity for peptide:MHC, and the cytokines produced by TH1 and TH2 cells themselves. If TH1 cells dominate an immune response, then a cell-mediated immune response is favored. If TH2 cells dominate, then a humoral immune response is favored.

Large group of different proteins sharing structural similarities that are involved in a variety of different functions. Include T cell receptors, Ab, adhesins, and MHC components

Ig superfamily

In addition to inhibiting protein synthesis, ____ increases phagocytosis by macrophages, boosts antibody production from B lymphocytes, and helps activate NK cells and cytotoxic T lymphocytes to kill virus-infected cells.

Infγ

____ is secreted by activated T lymphocytes. It has a broader range of effects than other interfereons.

Infγ

In T-cell tolerance, positive selection is associated with: presentation of self-antigens to the T cell production of a large number of B cells deletion of self-reactive T cells MHC restriction of T cell repertoire

MHC restriction of T cell repertoire

Antigens are also generated following phagocytosis. Material from digested pathogens are chopped up and attached to _____ __________.

MHCII molecules

Only T cells with the CD4 receptor interact with ____ ________

MHCII molecules

Humoral Response: When antigen binds, it triggers a signal transduction cascade that initiates rapid cell division. The resulting cells differentiate into two types of cell:

Plasma cells and memory B cells

_____ _____ ___ ____ _____ is a member of the ATP-binding-cassette transporter family. It delivers cytosolic peptides into the endoplasmic reticulum (ER), where they bind to nascent MHC class I molecules

Transporter associated with antigen processing (TAP)

Why are so many different cytokines needed, considering that some of them have the same effect on a particular cell or tissue?

Redundancy is key for a system's proper and efficient function. Should any part of the system fail, a redundant component can take over and achieve the same function. In addition, many different functions of the immune system are modulated by very carefully controlled "blends" of different cytokines, often in a synergistic approach.

Why are Toll-like receptors (TLRs) important for adaptive immune responses?

Stimulation of TLRs on dendritic cells by pathogen components induces the expression of chemokine receptor CCR7 on the dendritic cell. This enables dendritic cells laden with pathogen antigens to migrate from the site of infection to the nearest draining lymph node in response to chemokines produced by the lymph node. Stimulation of TLRs and other receptors on dendritic cells and macrophages also induces the expression of B7 co-stimulatory molecules, which makes these cells into professional antigen-presenting cells that are able to activate naive T cells.

The T cell recognizes and interacts with the antigen- MHC II molecule complex on the membrane of the antigen-presenting cell. An additional co-stimulatory signal is then produced by the antigen-presenting cell, leading to activation of the __ cell

T

Which of the following is not an example of a professional antigen-presenting cell? B cell Dendritic cell Macrophage T cell

T cell Professional antigen-presenting cells have MHC class II molecules on their surface.

Why is it that the bulk of central tolerance is achieved by mechanisms that affect T cells (ie, tolerance and negative selection) even though B cells can also be self-reactive?

T cells play a major role in B cell activation by providing a feedback signal to B cells that have presented antigen peptides to the T cell; in fact, a strong antibody response by a B cell is dependent on a T cell feeding back to that B cell once the T cell has recognized the antigen peptide presented by the B cell. If the T cell that can recognize that particular antigen peptide is not present, this feedback mechanism cannot occur, and the B cell does not continue in its activation against the Ag. Thus a lack of T-cell help against self-antigens (because of the elimination of self-reactive T cells by central tolerance ) plays a major role in B cell tolerance against that self antigen

This inflammatory cytokine has been implicated in septic shock resulting from infections with gram-negative bacteria: IFN-γ IL-1 TNF-α IL-6

TNF-a This cytokine was originally isolated from tumor cells.

Antigen is engulfed by these cells, digested and bound to MHC II molecules which are placed on the surface of the antigen presenting cell. The antigen presenting cells interact with _____________. The T helper cell binds the antigen and this triggers a series of events that eventually activates the B and Tc cells to perform their functions in adaptive immunity.

Th cells (T helper cell)

three types of lymphocytes

Th cells, B cells, Tc cells

Expression of IFN-γ is induced in a CD4 TH1 cell under the direction of the transcription factor ______.

a. T-bet

Co-stimulatory signals induced through CD28 cause(s) _____. (Select all that apply.)

a. activation of Jun, a component of the AP-1 transcription factor, c. activation of protein tyrosine kinase Lck

Where in the body do APCs go to present endogenous antigens to cytotoxic T cells? a. lymph nodes b. thymus c. spleen d. bone marrow

a. lymph nodes

Which of the following is NOT a function of an antibody? a. to make cytoplasmic membranes more permeable through the stimulation of IL-10 b. to activate complement c. to stimulate phagocytosis by opsonization d. to block bacterial adhesion molecules

a. to make cytoplasmic membranes more permeable through the stimulation of IL-10

Wha tis the main function of B lymphocytes? a. to secrete soluble antibodies b. to attack intracellular pathogens c. to activate T lymphocytes d. to activate antigen-presenting cells

a. to secrete soluble antibodies

Signal transducers and activators of transcription (STATs) are _____ that are phosphorylated by _____.

a. transcription factors; JAKs

The main function of Th1 T helper cells is to: stimulate inflammation. activate humoral immune responses. activate cell-mediated immune responses. inhibit all immune responses.

activate cell-mediated immune responses Th1 T helper cells are capable of stimulating cytotoxic T cells.

B cells are ______ when antigen binds on the B cell surface followed by a co-stimulatory signal from a Th cell.

activated

In order for the helper T cell to stimulate the B cell both must be ________. This usually requires that the B cell internalize the antigen, process it, and then present it on the cell surface bound to MHCII molecule.

activated

Inflammatory response that is the result of macrophage activation via surface PRRs of PAMPs on pathogen with the release of IL-1, IL-6, and TNF-a

acute phase response

extracellular and intracellular space is defended by your ________ immune response

adaptive

Family of proteins involved in cell-to-cell attachment; plays a major role in cell-to-cell interactions and in cell locomation

adhesins

Fos, a component of the transcription factor AP-1, is activated during T-cell signaling by a process involving a GTP-binding protein called _____.

b. Ras

Which of the following is a protein tyrosine kinase involved in T-cell activation culminating in T-cell proliferation and differentiation?

b. ZAP-70

What is one reason why active immunity is more advantageous than passive immunity? a. passive is always better b. active immunity leads to the development of immunological memory c. active immunity is fast-acting d. active immunity is slower and less likely to produce mistakes

b. active immunity leads to the development of immunological memory

IL-4 is involved in _________. a. B cell suppression b. differentiation of native T cells to the Th2 cells c. MHC class switching d. systemic inflammation

b. differentiation of native T cells to Th2 cells

Immunity that is passed from mother to child through the placenta is what type of immunity? a. naturally acquired active immunity b. naturally acquired passive immunity c. artificially acquired active immunity d. artificially acquired passive immunity

b. naturally acquired passive immunity

Which of the following cells is NOT an antigen-presenting cell (APC)? a. macrophage b. neutrophil c. B cell d. dendritic cell

b. neutrophil

Which type of immunity is acquired with the help of donor antibodies? a. active immunity b. passive immunity c. active and passive immunity d. neither active nor passive immunity

b. passive immunity

How are B cells activated without the help of T cells? a. this cannot happen b. repetitive epitopes allow B cell receptor cross-linking, which leads to cell activation and proliferation c. B cells get help from the complement system d. B cells get help from macrophages instead

b. repetitive epitopes allow B cell receptor cross-linking, which leads to cell activation and proliferation

What must happen before exogenous antigens are presented? a. enzymes are excreted by the APC to kill the pathogen b. the pathogen is internalized by the APC and then digested to create peptide antigens c. they must be combined with MHC class I molecules d. APCs must activate B cells

b. the pathogen is internalized by the APC and then digested to create peptide antigens

In general, antibody produced by B cell's bind to pathogens outside the cells and limits the number of cells that _________ infected.

become

Which of the following describes an activated dendritic cell upon arriving in a lymph node?

c. Bears highly elaborated finger-like processes called dendrites

The process by which cytotoxic T cells kill their targets involves _____. (Select all that apply.)

c. DNA fragmentation in lengths of multiples of 200 base pairs in the target cell, d. shedding of membrane-bound vesicles and shrinking of the target cell , e. release of granzyme, perforin, and granulysin by the cytotoxic T cell

What type of lymphocyte is responsible for killing abnormal or virus-infected cells? a. B lymphocyte b. helper T cell c. cytotoxic T cell d. plasma cell

c. cytotoxic T cell

Where within a cell are MHC class I molecules synthesized? a. cytoplasmic membrane b. Golgi body c. endoplasmic reticulum d. nucleus

c. endoplasmic reticulum

Viruses and some intracellular bacteria induce dendritic cells to secrete ________ to stimulate differentiation of T cells to the Th1 cells. a. tumor necrosis factor alpha b. gamma interferon c. interleukin 12 d. perforin

c. interleukin 12

Which statement regarding memory B cells is most accurate? a. they last 2-3 weeks in lymphoid tissues b. their main function is to constantly secrete antibodies c. they can last up to 20 years in lymphoid tissues d. they activate T cells upon a reinfection event

c. they can last up to 20 years in lymphoid tissues

What is the benefit of memory T cells that remain in the lymphoid tissues for years after an infection? a. they are readily available for quick antibody production b. they are readily available for activation by APCs c. they provide a quick response without the need for interaction with APCs d. memory T cells are not beneficial

c. they provide a quick response without the need for interaction with APCs

Which of the following is an example of artificially acquired active immunity? a. receiving an antiserum injection b. receiving an antitoxin injection c. vaccination d. exposure to a pathogen in the environment

c. vaccination

T cell mediated---> cytotoxic T cells---> kill infected cells primarily deals with intracellular threats (recognize antigens displayed on the surfaces of the mammalian cell)

cellular immunity

Peptide mediator that attracts chemotatic cells to a particular site; regulates the recruitment and movement of a variety of different cells

chemokines

How are T-dependent antigens different from T-independent antigens? a. T-dependent antigens are most commonly bacterial flagella b. T-dependent antigens are most commonly bacterial lipopolysaccharide (LPS) c. T-dependent antigens have more repetitive epitopes d. T-dependent antigens lack large, repetitive epitopes

d. T-dependent antigens lack large, repetitive epitopes

Why does the body mount a cell-mediated immune response? a. to fight intracellular pathogens b. to fight abnormal body cells c. in response to specific endogenous antigens d. all of the above

d. all of the above

What is the role of T lymphocytes in adaptive immunity? a. to carry out antibody immune responses b. to carry out cell-mediated immune responses c. to act against intracellular pathogens d. both b and c

d. both b and c

In secondary lymphoid tissues dendritic cells are located in _____, whereas B cells are present in _____.

d. cortical T-cell areas; lymphoid follicles

What is the difference between processing of endogenous antigens and that of exogenous antigens? a. if there are endogenous antigens present, the cell undergoes apoptosis b. endogenous antigens are presented to B cells, while exogenous antigens are presented to T cells c. endogenous antigens are presented by major histocompatibility complex (MHC) class II, exogenous by MHC class I d. endogenous antigens are presented by MHC class I, exogenous by MHC class II

d. endogenous antigens are presented by MHC class I, exogenous by MHC class II

Which class of antibody is most commonly associated with mucous membranes and secretions? a. immunoglobulin E (IgE) b. Immunoglobulin D (IgD) c. Immunoglobulin M (IgM) d. Immunoglobulin A (IgA)

d. immunoglobulin A (IgA)

Which of the following statements best describes the level of specificity involved in an adaptive immune response? a. responses are so specific that if a new pathogen invades the body, the adaptive immune system is ineffective b. adaptive immune responses are basically the same as innate immune responses c. there is a general set of responses that can be used against generalized pathogen antigens d. responses are precisely tailored against specific pathogens

d. responses are precisely tailored against specific pathogens

Binding of _____ to _____ induces T-cell proliferation and differentiation of activated T cells.

d.IL-2; the high affinity IL-2 receptor

phagocytosis of intact pathogens, and pinocytosis of soluble antigens

dendritic cells

T cells must be able to distinguish self from non-self. The process is referred to as the ____________________

development of self-tolerance

stage of development of T cells in which the cells express both CD4 and CD8

double positive lymphocytes

Cytokine receptors are associated with cytoplasmic protein kinases called _____, which become activated when the cytokine receptors bind to their respective cytokines.

e. JAKs

Think of major histocompatibility complex I (MHC I) as flag poles on which a portion of ______ protein made in a cell is displayed.

every

two compartments found within the mammalian body

extracellular space and intracellular space

A set of alleles from a particular chromosome that are transmitted together

haplotype

CD4+ subset of T cells that modulate and coordinate an immune response, usually via the secretion of elected cytokines

helper T cells

B cell mediated----> plasma cells----> immunoglobulins (antibodies) primarily deals with extracellular threats (interacts with pathogens and their toxic products outside cells)

humoral immunity

Group of proteins belonging to the adhesins family

integrins

When that MHC I - bound antigen is detected the cytotoxic T cell initiates any of a number of process intended to ____ the infected cell.

kill

The Cr51 release assay measures: proliferation of lymphocytes to foreign antigens. the concentration of cytokines released from a cell population. killing of labeled target cells by cytotoxic T cells. None of the above

killing of labeled target cells by cytotoxic T cells Cr51 is released from lysed cells.

In a one-way mixed lymphocyte culture: the uptake of tritiated thymidine decreases with an increase in lymphocyte proliferation. lymphocytes from one subject are prevented from proliferating by pretreatment with radiation or mitomycin. histocompatible lymphocytes stimulate each other to proliferate. lymphocyte proliferation is measured after a few hours of incubation of lymphocytes from two different sources with each other.

lymphocytes from one subject are prevented from proliferating by pretreatment with radiation or mitomycin. The one-way mixed lymphocyte culture is used to determine the response of lymphocytes from one individual to those from another individual. In a one-way mixed lymphocyte culture, lymphocytes from one subject are prevented from proliferating by pretreatment with radiation or mitomycin. This is done so that all proliferation occurring reflects the response of one set of lymphocytes to different histocompatibility antigens on the other set of lymphocytes.

phagocytosis of intact pathogens

macrophages

All cells express specialized presenting molecules called ______________ proteins on the cell surface

major histocompatibility complex I (MHC I)

long lived clonal progeny of the parent, ready to respond very quickly if the antigen is encountered again. (Antigen-experienced cells)

memory B cells

Professional antigen presenting cells can be _____, (eg. macrophages) or _______ (eg. dendritic cells).

mobile or fixed

Action of cytokine or hormone on a nearby cell or tissue

paracrine effect

produce antibody at rates of about 2000 molecules per second

plasma cells

Process in the development of thymocytes in which the MHC restriction of the immune repertoire of the host is achieved

positive selection

In T-cell tolerance, negative selection is associated with: presentation of self-antigens to the T cell MHC restriction of the T cell deletion of self-reactive antigen-presenting cells elimination of T-independent antigens

presentation of self-antigens to the T cell

If the T cell receptor (cell) binds weakly, the cell is released from the thymus and travels to a ____ ______ _______ (eg. lymph nodes), where is rests until called upon latter in life.

secondary lymphoid tissue

B cells are lymphocytes produced in the bone marrow that are covered by about 50,000 molecules of a ____ membrane bound receptor antibody on their surface. This structure is called the ______________________

single; B cell receptor (BCR).

Combined action of 2 entities is greater than the sum of their actions separately

synergistic

The condition X-linked severe combined immunodeficiency (X-SCID) is due to a mutation in the gene coding for a subunit of: the IL-2 receptor. IL-2. the T-cell receptor. MHC class I.

the IL-2 receptor This subunit is shared by receptors for several cytokines.

David (the bubble boy's) SCID was due to defects in genes encoding for: the IL-2 receptor alpha the IL-2 receptor gamma the CD4 molecule the CD8 molecule

the IL-2 receptor gamma

lL-2 is made by T cells and can trigger T cellls. true or false

true