Chapter 8 & 9 Practice Problems

A B cell's sensitivity to antigen can be increased 1000-10,0000-fold by a. simultaneously ligating the B-cell receptor and co-receptor b. simultaneously ligating the B-cell receptor and Toll-like receptor c. ligating the B-cell co-receptor and phosphorylating Ig-α ITAMs d. increasing levels of Syk proteins in the vicinity of co-receptor ligation e. ligating cytokine receptors on the B-cell surface

a

All of the following indicate correct intermolecular associations except _____. a. Janus kinases (JAKs): serglycin b. L-selectin: GlyCAM-1 c. VLA-4: VCAM-1 d. JAKs: signal transducers and activators of transcription (STATs) e. CD40: CD40 ligand.

a

All of the following statements regarding interleukin-2 (IL-2) or its receptor are true except _____. a. The low-affinity IL-2 receptor is a membrane-bound heterodimer composed of α and β chains. b. IL-2 production increases approximately 100-fold if a co-stimulatory signal is delivered. c. T-cell proliferation occurs upon binding of IL-2 to the high-affinity IL-2 receptor. d. The high-affinity IL-2 receptor is assembled after T-cell activation. e. Rapamycin is an immunosuppressive drug that inhibits signaling of IL-2 through the IL-2 receptor.

a

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 b. CD2; LFA-3 c. MHC class II; T-cell receptor d. L-selectin; GlyCAM-1 e. ICAM-1; LFA-1

a

Expression of IFN-γ is induced in a CD4 TH1 cell under the direction of the transcription factor ______. a. T-bet b. FoxP3 c. AP-1 d. GATA-3 e. NFAT

a

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 b. fewer c. the same number of

a

Naive B cells search for specific antigen displayed by follicular dendritic cells in primary follicles. Naive T cells, however, search for specific antigen presented by ______. a. dendritic cells b. subcapsular sinus macrophages c. medullary sinus macrophages d. centrocytes e. tingible body macrophages

a

Naive lymphocytes homing to lymphoid tissue use _____ to bind to CD34 and GlyCAM-1 on high endothelial venules. a. L-selectin b. CD2 (LFA-2) c. ICAM-1 d. CCL21 e. CD28

a

Signal transducers and activators of transcription (STATs) are _____ that are phosphorylated by _____. a. transcription factors; JAKs b. protein kinases; other STATs c. cytokine receptors; JAKs d. cytokines; cytokine receptors e. transcription factors; Lck

a

The primary effect of inositol trisphosphate (IP3) during T-cell activation is to _____. a. cause an increase in cytosolic calcium concentration b. activate phospholipase C-γ c. activate a MAP kinase cascade d. facilitate the differentiation of immature effector T cells e. align the microtubule-organizing center toward the antigen-presenting cell.

a

The release of lytic granules from cytotoxic T cells is aimed specifically at infected target cells while preserving the integrity of neighboring, uninfected cells. This is best explained by the observation that _____. a. only target cells bearing appropriate peptide:MHC class I complexes are susceptible to necrosis b. redistribution of lytic granules in the T cell delivers them to confined areas on the target cell in contact with the T cell c. regulatory T cells deliver survival signals to uninfected neighboring cells that renders them resistant to cytotoxins d. the amount of cytotoxins in a given cytotoxic T cell is so limited that only the cell closest to the T cell will succumb to the effects of perforin and granzyme e. uninfected cells are highly resistant to the effects of cytotoxins

a

When bound to CR1, C3b is cleaved by _____, generating pathogen-associated B-cell co-receptor ligands. a. factor I b. CR2 c. C3d d. CD19 e. Lyn

a

Which of the following is an accurate description of how centroblasts differ from centrocytes? a. Centroblasts cease their expression of cell-surface immunoglobulins. b. Centroblasts divide more slowly than centrocytes. c. Centroblasts express CD44 but centrocytes do not. d. Centrocytes, but not centroblasts, initiate the process of isotype switching. e. Centroblasts participate in affinity maturation

a

Which of the following is associated with immature dendritic cells in the skin before their activation? a. Toll-like receptors b. CTLA4 c. CCR7 d. DC-SIGN e. ICAM-3

a

Which of the following is not produced by TH17 cells? a. ICOS (inducible T-cell co-stimulator) b. IL-17 c. CD4 d. IL-21 e. STAT3

a

Clonal expansion and differentiation of naive T cells to effector T cells depends on the activation of the transcription factor(s) _____ through a ZAP-70-mediated signal transduction pathway. (Select all that apply.) a. AP-1 b. IL-2 c. NFκB d. NFAT e. Ras.

a, c, d

Which of the following cytokines is not secreted by TH2 cells? (Select all that apply.) a. IFN-γ b. IL-4 c. IL-5 d. IL-10 e. TGF-β f. lymphotoxin (LT).

a, f

All of the following are true in reference to T-cell priming except _____. a. It occurs in primary lymphoid organs b. It transforms naïve T cells into differentiated effector T cells c. It is the first stage of a primary adaptive immune response d. It requires interaction between naïve T cells and antigen-presenting cells e. It takes place in many locations including, but not limited to, lymph nodes, Peyer's patched, and the tonsils

a. It occurs in primary lymphoid organs

Homing of effector T cells to inflamed tissue facilitated by the upregulation of _____ on the surface of the effector T cell. a. VLA-4 b. L-selectin c. CD28 d. VCAM-1 e. B7

a. VLA-4

A primary focus of clonal expansion is best described as _____. a. the location in the B-cell zone where conjugate pairs of B and T cells undergo cellular proliferation, isotype switching, and somatic hypermutation b. the location in the medullary cords where conjugate pairs of B cells and T cells undergo cellular proliferation and IgM is secreted c. the dark zone of the germinal center where centroblasts divide and pack closely together d. the initial wave of B-cell proliferation induced by T-independent antigens.

b

All of the following are included in the central supramolecular activation complex (c-SMAC) except _____. a. CD4 or CD8 b. ICAM-1 c. CD28 d. T-cell receptor e. PKC-θ

b

C3d and iC3b are breakdown products of _____, which binds to _____ of the B-cell co-receptor. a. C3a; CR2 b. C3b; CR2 c. C3c; CD81 d. C3c; CD19 e. C3b; CD19

b

During cytokine signaling, _____ translocate(s) to the nucleus and direct(s) the upregulation of gene expression. a. perforin b. STATs c. CD40 ligand d. TGF-β e. CXCL2

b

Fos, a component of the transcription factor AP-1, is activated during T-cell signaling by a process involving a GTP-binding protein called _____. a. inositol trisphosphate b. Ras c. protein kinase C-θ d. Lck e. ZAP-70

b

Identify the mismatched pair. a. TFH cells: Bcl6 b. TH1: GATA3 c. TH1 cells: IFN-γ d. TH2: IL-4 e. Treg: TGF-\beta

b

If a centrocyte does not interact with antigen and engage CD40 shortly after its derivation, then _____. a. it recommences somatic hypermutation b. it undergoes apoptosis c. it moves back into the dark zone of the germinal center and switches its isotype d. its surface immunogloblulin levels decrease and proliferation recommences

b

Plasma cells and memory B cells differentiate most immediately from _____. a. centrocytes b. centroblasts c. B-1 cells d. IgG-secreting B cells

b

The co-stimulatory molecule _____ on professional antigen-presenting cells binds _____ on the surface of naive T cells. a. DC-SIGN; ICAM-3 b. B7; CD28 c. ICAM-1; LFA-1 d. MHC class II; T-cell receptor e. MHC class II; CD4

b

The process that drives an increase in antibody affinity for antigen is known as _____. a. apoptosis b. affinity maturation c. antibody-dependent cell-mediated cytotoxicity d. opsonization e. clonal expansion

b

Which of the following is a protein tyrosine kinase involved in T-cell activation culminating in T-cell proliferation and differentiation? a. AP-1 b. ZAP-70 c. NFκB d. NFAT e. calcineurin

b

Which of the following is a characteristic of follicular dendritic cells in the primary follicles of secondary lymphoid tissues? (Select all that apply.) a. They are bone marrow derived hematopoietic cells. b. They provide a stable depository of intact antigens able to bind to B-cell receptors. c. They have a large surface area as a result of forming dendrites. d. They internalize immune complexes through CR2 receptor cross-linking. e. They produce cytokines that induce B cells to proliferate and become centroblasts

b, c

What is the fate of centrocytes in which somatic hypermutation has resulted in high-affinity receptors for antigen? (Select all that apply.) a. They die by apoptosis. b. They express Bcl-xL. c. They process antigen and present it to TFH cells. d. CD40 on the centrocyte engages with CD40 ligand on TFH cells. e. They undergo phagocytosis by tingible body macrophages

b, c, d

Proliferating centroblasts use the DNA-modifying enzyme activation-induced cytidine deaminase for ________. (Select all that apply.) a. cell proliferation b. somatic hypermutation c. apoptosis d. upregulation of CD40 e. isotype switching

b, e

_____ cells remain in, rather than leave, the secondary lymphoid organs in which they differentiated. a. CD4 TH1 cells b. CD4 TFH cells c. CD8 cytotoxic T cells d. Regulatory CD4 T cells e. All of the above

b. CD4 TFH cells

Linked recognition is best described as _____. a. The delivery of the co-stimulatory signal by antigen-presenting cells to T cells b. Cooperation between T follicular helper (TFH) and naïve B cells bearing specificity for different epitopes of the same antigen and where the B cell serves as the antigen presenting cell c. Linking Toll-like receptors and the innate immune response d. The interaction between processed antigenic peptides and MHC molecules during antigen presentation e. The region of contact between T cells and antigen-presenting cells involving cell-adhesion molecules and other cell-surface receptor-ligand pairs

b. Cooperation between T follicular helper (TFH) and naïve B cells bearing specificity for different epitopes of the same antigen and where the B cell serves as the antigen presenting cell

Which of the following explains why dendritic cells, but not macrophages or B cells, contribute to the activation of naïve T cells? a. Macrophages and B cells do not express MHC class II molecules until they are activated. b. Dendritic cells upregulate B7 after engaging innate immunity receptors at site of infection. c. Dendritic cells express higher levels of CTLA4. d. Macrophages and B cells do not process antigen. e. Dendritic cells use Toll-like receptors to hold antigen in place for extended periods of time.

b. Dendritic cells upregulate B7 after engaging innate immunity receptors at site of infection.

Which of the following cell types is unable to interact with naïve T cells and induce their activation? (Select all that apply.) a. B cells b. Macrophages resident in infected tissues c. Macrophages resident in secondary lymphoid tissue d. Interdigitating reticular cells e. Immature dendritic cells

b. Macrophages resident in infected tissues e. Immature dendritic cells

Dendritic cells take up, process or present antigen by all of the following routes except _____. a. receptor-mediated endocytosis of bacteria b. macropinocytosis of bacteria or viruses c. uptake of viruses using Toll-like receptor TLR9 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

c

Engulfment of apoptotic centrocytes is facilitated by _____ in germinal centers. a. follicular dendritic cells b. immune-complex coated bodies (iccosomes) c. tingible body macrophages d. antigen-specific B cells e. antigen-specific TFH cells

c

Immunoreceptor tyrosine-based activation motifs (ITAMs) are located on _____. a. the cytoplasmic tails of IgM b. tyrosine kinases Blk, Fyn, and Lyn c. the cytoplasmic tails of Igα and Igβ d. breakdown products of C3b deposited on pathogen surfaces e. thymus-independent antigens.

c

In a person with lepromatous leprosy, the lesions would contain mRNA for _____. a. lymphotoxin (LT) b. IL-2 c. IL-5 d. IFN-γ e. granulysin

c

Lymphoblasts upregulate a transcription factor called _____ when they terminally differentiate into plasma cells. a. NFκB b. Bcl-xL c. B-lymphocyte induced maturation protein 1 (BLIMP-1) d. CD40 e. ICAM-1

c

Talin is best described as a _____. a. protein tyrosine kinase b. transcriptional activator c. cytoskeletal protein d. pro-inflammatory cytokine e. cytokine receptor that associates with Janus kinases (JAKs)

c

The B-cell co-receptor is composed of a. Igα; Igβ; CD19 b. Igα; Igβ; Lyn tyrosine kinase c. CR2 (CD21); CD19; CD81 d. CD14; CD19; CD81 e. CD40; MHC class II; CED19

c

The enzyme that generates diacylglycerol (DAG) and inositol trisphosphate (IP3) from phosphatidylinositol bisphosphate (PIP2) is _____. a. protein kinase C-θ (PKC-θ) b. calcineurin c. phospholipase C-γ (PLC-γ) d. protein tyrosine kinase ZAP-70 e. protein tyrosine kinase Lck

c

Tuberculoid leprosy is characterized by a _____-type response in which patients _____. a. TH2; usually survive b. TH2; eventually die c. TH1; usually survive d. TH1; eventually die e. Treg; eventually die

c

Which of the following describes an activated dendritic cell upon arriving in a lymph node? a. located in follicles and medulla of the lymph node b. associated mainly with antigen uptake and processing c. bears highly elaborated finger-like processes called dendrites d. expresses low levels of MHC class II molecules e. carries out apoptosis of lymphocytes.

c

Which of the following is a mismatch? a. centroblast : undergo somatic hypermutation b. tingible body macrophage: engulf apoptotic centrocytes c. naive B cell : differentiate under the influence of DC d. memory B cell : differentiate under the influence of an IL-4-secreting TFH cell : e. follicular dendritic cells (FDC): not bone marrow-derived hematopoietic cells

c

Which of the following is incorrect regarding sphingosine 1-phosphate (S1P) and its receptor? a. It is a lipid that has chemotactic activity. b. S1P gradients are established in lymph nodes with lowest concentrations in T-cell areas. c. CD69 upregulates S1P receptor expression on the surface of naive T cells. d. S1P is synthesized by all cells.

c

Which of the following is produced by CD8 T cells? a. IL-10 b. TGF-β c. IFN-γ d. IL-4 e. IL-17

c

Which of the following statements is false regarding CD8 T cells? a. CD8 T cells have only one effector function, which is cytotoxicity. b. Compared with naive CD4 T cells, naive CD8 T cells have more stringent requirements for co-stimulatory activity. c. Effector CD8 cells require co-stimulation to kill their target cells. d. The most potent antigen-presenting cell for naive CD8 T cells is the dendritic cell

c

_____ is a mechanism that drives the preferential selection of immunoglobulins with the highest affinity for antigen. a. Anergy b. Isotype-switching c. Affinity maturation d. Antibody-dependent cell-mediated cytotoxicity e. Transcytosis

c

_____ is a second messenger in the T-cell signaling pathway leading to the activation of NFAT. a. diacylglycerol (DAG) b. NFκB c. inositol trisphosphate d. Fos e. Ras

c

The process by which cytotoxic T cells kill their targets involves _____. (Select all that apply.) a. inducing the target cell to undergo necrosis b. inducing apoptosis (programmed cell death) in the cytotoxic T cell 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

c, d, e

Which of the following is a feature of regulatory T cells (Treg)? (Select all that apply.) a. Treg express CD8 and control effector cells by inducing apoptosis. b. Treg express high levels of CD25 (IL-2 receptor α chain) and secrete pro-inflammatory cytokines such as IFN-γ. c. Physical association between Treg and their target cells is mandatory for Treg function. d. By interacting with dendritic cells in secondary lymphoid tissue, Treg prevent the interaction and activation of naive T cells. e. Treg secrete TGF-β and suppress effector T-cell function.

c, d, e

Which of the following cytokines is secreted by both CD8 T cells and TH1 cells? (Select all that apply.) a. IL-4 b. IL-5 c. IFN-γ d. TNF-α e. IL-13 f. lymphotoxin (LT)

c, f

Antigen recognition by T cells in the absence of co-stimulation results in a. Upregulation of B7 b. Expression of the high-affinity IL-2 receptor c. T-cell anergy d. T-cell apoptosis e. Phosphorylation of immunoreceptor tyrosine-based activation motifs.

c. T-cell anergy

A primary focus forms after a circulating naive B cell forms a conjugate pair with _____ in the _____ of a lymph node. a. TH1 cell; B-cell zone b. cytotoxic T cell; T-cell zone c. follicular dendritic cell; germinal center d. TFH; medullary cords e. CD40 ligand; T-cell zone

d

Activated T cells express _____, which binds to B7 with 20 times higher affinity than CD28 and results in _____ of T-cell activity and proliferation. a. high-affinity IL-2 receptor; stimulation b. CD40L; suppression c. VLA-4; stimulation d. CTLA4; suppression.

d

All of the following statements refer to regulatory T cells except ____. a. they produce anti-inflammatory cytokines b. they express elevated levels of CD25 c. they express FoxP3 d. they enhance the production of new effector T cells e. they suppress the function of existing T cells

d

An important way in which effector T cells differ from naive T cells is that _____. a. the cell-surface level of LFA-1 is lower on effector T cells b. L-selectin is upregulated during differentiation of effector T cells c. cellular proliferation occurs after effector T cells leave the secondary lymphoid tissues d. the provision of co-stimulatory signals is not required to induce a response by effector T cells e. effector T cells do not recirculate between lymph, blood, and secondary lymphoid tissues

d

Binding of _____ to _____ induces T-cell proliferation and differentiation of activated T cells. a. CD4; MHC class II b. CD28; B7 c. LFA-1; ICAM-1 d. IL-2; the high-affinity IL-2 receptor e. IL-2; the low-affinity IL-2 receptor

d

Complexes of IgG bound to soluble multivalent antigens can activate the classical pathway of complement, resulting in the deposition of _____ on the complex, targeting it for endocytic uptake by cells bearing _____. a. C4b; CR2 and Fc receptors b. C3b; CR2 and Toll-like receptors c. C5-9; CR1 and Fc receptors d. C3b; CR1 and Fc receptors

d

Dendritic cells are important in adaptive immune responses since? Mark the wrong answer. a. Dendritic cells engulf, process and then transport antigens to a nearby secondary lymphoid tissue. b. DC communicate with naïve T cells through an immunological synapsis and activate them. c. DC dictate the type of effector T cell that a naïve T cell will become d. DC secrete IL-2 which will activate effector T cells e. DC will drive naïve T cells into an anergic condition if they are specific to a self antigen.

d

IL-4 is induced in a CD4 TH2 cell under the direction of the transcription factor _____. a. T-bet b. FoxP3 c. AP-1 d. GATA-3 e. NFAT

d

If a non-professional antigen-presenting cell that lacks co-stimulatory molecules presents peptide:MHC complexes to a T cell specific for that peptide, then _____. a. the T cell delivers a signal to the non-professional antigen-presenting cell to activate the expression of co-stimulatory molecules. b. the T cell begins to express the α chain of the IL-2 receptor. c. the T cell differentiates into a TH1 cell. d. T-cell tolerance occurs as a result of anergy. e. the T cell is more heavily reliant on signals transmitted through CD4 or CD8 in order to become activated.

d

IgM is particularly efficient at fixing complement because it _____. a. is a much larger antibody than the other isotypes b. has an extra CH domain c. is made first in an immune response and therefore has first access to C1q d. has five binding sites for C1q e. has easy access to extravascular areas

d

The Igα-associated tyrosine kinase _____ phosphorylates the cytoplasmic tail of CD19, which mediates signal transduction in activated B cells. a. CD81 b. Blk c. Fyn d. Lyn e. Syk

d

The main function of Bcl-xL is to _____ in the centrocyte. a. provide death signals b. induce somatic hypermutation c. upregulate the expression of activation-induced cytidine deaminase d. prevent apoptosis e. induce isotype switching

d

The primary focus of B-cell expansion forms in the _____, whereas a secondary focus of B-cell expansion creates the _____. a. T-cell area; medullary cords b. medullary cords; T-cell area c. T-cell area; B-cell area d. medullary cords; germinal center e. light zone; dark zone

d

Which of the following contributes to the activation of naive T cells? a. Neutrophils b. B cells c. Macrophages d. dendritic cells e. basophils

d

Which of the following is not produced by T follicular helper (TFH) cells? a. CD4 b. IL-4 c. IFN-γ d. TNF-α e. IL-21

d

Which of the following statements regarding leprosy is false? a. It is caused by the bacterium Mycobacterium leprae. b. Disease progression is influenced depending on whether the immune response is polarized toward either a TH1 or TH2 response. c. The tuberculoid form of leprosy is associated with localized inflammation and granuloma formation. d. In lepromatous leprosy, the patient makes a TH2 response that clears the mycobacteria from the body. e. The less severe form of leprosy presents with high levels of IL-2 and IFN-γ produced by responding T cells.

d

If CD4 or CD8 co-receptors are absent, they approximately _____ specific peptide:MHC complexes are needed to activate a T cell. a. Twice the number of b. 10 times the number of c. 20 times the number of d. 100 times the number of e. 1000 times the number of

d. 100 times the number of

Identify which of the following statements regarding naïve T cells is incorrect. a. Naïve T cells enter lymph node in two different ways, from the blood or from the lymph. b. Naïve T cells can only be activated in secondary lymphoid tissues. c. Naïve T cells differentiate into effector T cells after T-cell priming has occurred. d. Naïve T cells occupy both the cortex and the medulla of the lymph nodes. e. Naïve T cells are only activated by dendritic cells, not by macrophages or B cells.

d. Naïve T cells occupy both the cortex and the medulla of the lymph nodes.

Which of the following statements regarding T cells activated by specific antigen is incorrect? a. They receive co-stimulatory signals through CD28 b. They suppress expression of sphingosine 1-phosphate (S1P). c. They take several days before differentiating into effector T cells. d. They cease to secrete and respond to interleukin-2 (IL-2). e. They begin to express CTLA-4, which serves to limit T-cell proliferation.

d. They cease to secrete and respond to interleukin-2 (IL-2).

All of the following are correctly matched except _____. a. TH1: T-bet b. Treg: FoxP3 c. IL-12: dendritic cells d. TH17: RORγT e. TH2: Bcl6.

e

B cells migrating directly from a primary focus to the medullary cords in a lymph node after activation with a T-dependent antigen differentiate into plasma cells that secrete predominantly _____. a. IgD b. IgE c. sIgA d. IgG e. IgM

e

Many cytokine receptors are associated with cytoplasmic protein kinases called _____, which become activated when the cytokine receptors bind to their respective cytokines. a. ZAP-70 b. STATs c. Lck d. ITAMS e. JAKs

e

T cells failing to encounter specific antigen leave lymph nodes via the _________. a. germinal center b. bloodstream c. high endothelial venules d. afferent lymph e. efferent lymph.

e

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) a. immunoreceptor tyrosine-based activation motif (ITAM) b. polarization c. cross-presentation center d. granuloma e. immunological synapse.

e

Which of the following characteristics permits activated CD8 T cells to destroy any cell type harboring viable and replicating pathogens such as viruses? a. The pathogen is located in extracellular spaces. b. CD8 T cells enable macrophages to kill intracellular pathogens. c. Pathogen-derived peptides bind MHC class I molecules in endocytic vesicles found ubiquitously in most cell types. d. MHC class II molecules are expressed ubiquitously by most nucleated cells. e. MHC class I molecules are expressed ubiquitously by most nucleated cells

e

Which of the following is not a transcription factor, a component of a transcription factor, or an activator of transcription? a. FoxP3 b. AP-1 c. NFκB d. NFAT e. JAKs

e

When an immature dendritic cell becomes an activated dendritic cell, all of the following changes occur except _____. a. Confinement to T-cell regions of lymph node cortex b. Development of elaborate finger-like processes c. Upregulated expression of MHC class II at the cell surface d. Loss of antigen-processing functions e. Expression of Toll-like receptor TLR9

e. Expression of Toll-like receptor TLR9

Identify which of the following statements regarding naïve T cells is incorrect. a. Naïve T cells have the capacity to survive for many years as nondividing circulating cells in the absence of a specific antigen. b. Naïve T cells express LFA-1 molecules that change their conformation after encountering a specific peptide:MHC complex. c. Naïve T cells exit from the lymph nodes using the same route as effector T cells. d. Naïve T cells express ICAM-3, which binds to DC-SIGN on dendritic cells with high affinity. e. Naïve T cells express high levels of S1P receptors on their surface.

e. Naïve T cells express high levels of S1P receptors on their surface.

Match the T-cell type to its description: CD4 TH2 cells Description Bank: 1. Help basophils, mast cells, eosinophils and B cells respond to parasitic infection 2. Facilitate neutrophil response to fungal and extracellular bacterial infections 3. Suppress effector CD4 and CD8 T-cell function 4. Differentiate under the influence of IL-12 and IFN-γ 5. Induce apoptosis of target cells after targeted delivery of cytotoxins

1. Help basophils, mast cells, eosinophils and B cells respond to parasitic infection

Match the T-cell type to its description: CD4 TH17 cells Description Bank: 1. Help basophils, mast cells, eosinophils and B cells respond to parasitic infection 2. Facilitate neutrophil response to fungal and extracellular bacterial infections 3. Suppress effector CD4 and CD8 T-cell function 4. Differentiate under the influence of IL-12 and IFN-γ 5. Induce apoptosis of target cells after targeted delivery of cytotoxins

2. Facilitate neutrophil response to fungal and extracellular bacterial infections

Match the T-cell type to its description: Regulatory T cells (Treg) Description Bank: 1. Help basophils, mast cells, eosinophils and B cells respond to parasitic infection 2. Facilitate neutrophil response to fungal and extracellular bacterial infections 3. Suppress effector CD4 and CD8 T-cell function 4. Differentiate under the influence of IL-12 and IFN-γ 5. Induce apoptosis of target cells after targeted delivery of cytotoxins

3. Suppress effector CD4 and CD8 T-cell function

Match the T-cell type to its description: CD4 TH1 cells Description Bank: 1. Help basophils, mast cells, eosinophils and B cells respond to parasitic infection 2. Facilitate neutrophil response to fungal and extracellular bacterial infections 3. Suppress effector CD4 and CD8 T-cell function 4. Differentiate under the influence of IL-12 and IFN-γ 5. Induce apoptosis of target cells after targeted delivery of cytotoxins

4. Differentiate under the influence of IL-12 and IFN-γ

Match the T-cell type to its description: CD8 T cells Description Bank: 1. Help basophils, mast cells, eosinophils and B cells respond to parasitic infection 2. Facilitate neutrophil response to fungal and extracellular bacterial infections 3. Suppress effector CD4 and CD8 T-cell function 4. Differentiate under the influence of IL-12 and IFN-γ 5. Induce apoptosis of target cells after targeted delivery of cytotoxins

5. Induce apoptosis of target cells after targeted delivery of cytotoxins