Exam 4: T & B cell mediated immunity Flashcards
Which of the following is not produced by TH17 cells?
ICOS (inducible T-cell co-stimulator)
Which of the following is incorrect regarding sphingosine 1-phosphate (S1P) and its receptor?
CD69 upregulates S1P receptor expression on the surface of naive T cells.
During cytokine signaling, _____ translocate(s) to the nucleus and direct(s) the upregulation of gene expression.
STATs
Binding of _____ to _____ induces T-cell proliferation and differentiation of activated T cells.
IL-2; the high-affinity IL-2 receptor
Fos, a component of the transcription factor AP-1, is activated during T-cell signaling by a process involving a GTP-binding protein called _____.
Ras
Which of the following is a protein tyrosine kinase involved in T-cell activation culminating in T-cell proliferation and differentiation?
ZAP-70
Which of the following is not produced by T follicular helper (TFH) cells?
TNF-alpha
T cells failing to encounter specific antigen leave lymph nodes via the _________.
efferent lymph
Which of the following characteristics permits activated CD8 T cells to destroy any cell type harboring viable and replicating pathogens such as viruses?
MHC class I molecules are expressed ubiquitously by most nucleated cells.
Expression of IFN-gamma is induced in a CD4 TH1 cell under the direction of the transcription factor ______.
T-bet
In a person with lepromatous leprosy, the lesions would contain mRNA for _____.
IL-5
Which of the following statements is false regarding CD8 T cells?
Effector CD8 cells require co-stimulation to kill their target cells.
Identify the mismatched pair:
TH1: GATA3
All of the following statements refer to regulatory T cells except ____.
they enhance the production of new effector T cells
All of the following indicate correct intermolecular associations except _____.
Janus kinases (JAKs): serglycin
Proliferating centroblasts use the DNA-modifying enzyme activation-induced cytidine deaminase for ________.
somatic hypermutation and isotype switching
Engulfment of apoptotic centrocytes is facilitated by _____ in germinal centers.
tingible body macrophages
A primary focus of clonal expansion is best described as _____.
the location in the medullary cords where conjugate pairs of B cells and T cells undergo cellular proliferation and IgM is secreted
Immunoreceptor tyrosine-based activation motifs (ITAMs) are located on _____.
the cytoplasmic tails of Igalpha and Igbeta
The primary focus of B-cell expansion forms in the _____, whereas a secondary focus of B-cell expansion creates the _____.
medullary cords; germinal center
The B-cell co-receptor is composed of _________.
CR2 (CD21); CD19; CD81
A primary focus forms after a circulating naive B cell forms a conjugate pair with _____ in the _____ of a lymph node.
TFH; medullary cords
. If a centrocyte does not interact with antigen and engage CD40 shortly after its derivation, then _____.
it undergoes apoptosis
A B cell’s sensitivity to antigen can be increased 1000-10,0000-fold by _________.
simultaneously ligating the B-cell receptor and co-receptor
Identify the mismatched association.
tyrosine kinase Lyn: CD81
_____ is a mechanism that drives the preferential selection of immunoglobulins with the highest affinity for antigen.
Affinity maturation
Which of the following is consistent with a recently antigen-activated mast cell?
the absence of prepackaged granules
Which of the following is an accurate description of how centroblasts differ from centrocytes?
Centroblasts cease their expression of cell-surface immunoglobulins.
To mount the most effective antibody response that results in the synthesis of high-affinity antibodies, which of the following must occur?
isotype switching and affinity maturation
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 _____.
IgM
C3d and iC3b are breakdown products of _____, which binds to _____ of the B-cell co-receptor.
C3b; CR2
Which of the following is not a function of antibodies?
They exert toxic effects directly.
The symptoms of allergy and asthma are induced after cross-linking of IgE antibody on FcepsilonRI receptors found on the surface of _____.
basophils, eosinophils, and mast cells
The Ig-alpha-associated tyrosine kinase _____ phosphorylates the cytoplasmic tail of CD19, which mediates signal transduction in activated B cells.
Lyn
Of the Fc receptors for IgG, which one is similar to FcepsilonRI in its ability to bind antibody in the absence of antigen but does not transduce an activating signal until antigen cross-linking occurs?
FcgammaRI
Which of the following is able to bind to C1q?
IgM and C-reactive protein
FcRn has which of the following characteristics?
It transports IgG out of the blood into tissue across the endothelium; two molecules of FcRn are required to bind to each Fc region.
IgM is particularly efficient at fixing complement because it _____.
has five binding sites for C1q
Antibody-dependent cell-mediated cytotoxicity (ADCC) is carried out by _____ after cross-linking of IgG1 or IgG3 antibodies on _____ receptors.
NK cells; FcgammaRIII
A distinguishing feature of FcgammaRIIB1 compared with FcgammaRIIA is _____.
the existence of ITIMs in its cytoplasmic tails
Which of the following statements is true regarding the complement component C4B?
The gene for C4B is duplicated or deleted in some individuals.
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 _____.
C3b; CR1 and Fc receptors
The gamma chain of the FcgammaRI receptor is closely related to the _____, which contains _____.
zeta chain of the T-cell receptor complex; ITAM motifs
For IgG2 to be effective at stimulating uptake of IgG2-coated bacteria, _____.
an individual must express allotype H131 of FcgammaRIIA
_____ occurs as a result of influenza virus binding to oligosaccharide components on erythrocyte surfaces causing them to clump together.
Hemagglutination
Some types of B-cell tumor have been treated with rituximab, an anti-CD20 monoclonal antibody, which exerts its effect through a mechanism known as ______ involving the participation of NK cells.
antibody-dependent cell-mediated cytoxicity
_____ is a second messenger in the T-cell signaling pathway leading to the activation of NFAT.
inositol trisphosphate (IP3)
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 _____.
T-cell tolerance occurs as a result of anergy.
The enzyme that generates diacylglycerol (DAG) and inositol trisphosphate (IP3) from phosphatidylinositol bisphosphate (PIP2) is _____.
phospholipase C-gamma (PLC-gamma)
Signal transducers and activators of transcription (STATs) are _____ that are phosphorylated by _____.
transcription factors; JAKs
Which of the following molecules is not elevated on the surface of memory B cells compared with naive B cells?
CD45RA
Which of the following cytokine(s) is not secreted by TH2 cells?
IFN-gamma and lymphotoxin (LT)
Which of the following cytokine(s) is(are) secreted by both CD8 T cells and TH1 cells?
IFN-gamma and lymphotoxin (LT)
Which of the following is produced by CD8 T cells?
IFN-gamma
Tuberculoid leprosy is characterized by a ______-type response in which patients _____.
TH1; usually survive
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.
AP-1, NFkappaB, and NFAT
Many cytokine receptors are associated with cytoplasmic protein kinases called _____, which become activated when the cytokine receptors bind to their respective cytokines.
JAKs
An important way in which effector T cells differ from naive T cells is that ____.
The provision of co-stimulatory signals is not required to induce a response by effector T cells
IL-4 is induced in a CD4 TH2 cell under the direction of the transcription factor ____.
GATA-3
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 y the observation that _____.
Redistribution of lytic granules in the T cell delivers them to confined areas on the target cell in contact with the T cell.
Which of the following statements regarding leprosy is false?
In lepromatous leprosy, the patient makes a TH2 response that clears the mycobacteria from the body.
