T Cell Mediated Immunity Flashcards
Adaptive cell-mediated immunity involves the generation of activated antigen-specific effector
a. antibodies.
b. B cells.
c. cytokines.
d. macrophages
e. T cells.
e. T cells.
T cells are activated to armed effector cells when they encounter antigen on
a. blood-borne pathogens.
b. bone marrow stromal cells.
c. professional APC.
d. virus-infected tissues.
e. all of the above.
c. professional APC.
T cells move from the circulation into the peripheral lymphoid tissues when they bind
a. antigen.
b. APC.
c. B7.
d. homing molecules.
e. vascular addressins.
e. vascular addressins.
LFA-1 is a(n)
a. co-receptor on T cells.
b. co-stimulatory molecule on APC.
c. cytokine receptor on APC.
d. integrin on T cells.
e. vascular addressin on HEV.
d. integrin on T cells.
The antigen specificity of Th activation by macrophages is enhanced by the
a. ability of each macrophage to present only specific epitopes to T cells.
b. binding of T cell adhesion molecules only to macrophages presenting the antigen recognized by the T cell.
c. specificity of CD4 binding to Class II MHC on the macrophage.
d. upregulation of CD4 or CD8 co-receptors following antigen binding.
e. upregulation of co-stimulatory molecules only on macrophages which have contacted foreign antigen
e. upregulation of co-stimulatory molecules only on macrophages which have contacted foreign antigen
Membrane events required for Th activation include all of the following EXCEPT binding of T cell
a. CD4 to APC Class II MHC.
b. CTLA-4 to APC B7.
c. high affinity IL-2 receptor to IL-2.
d. LFA-1 to APC ICAM.
e. TCR to peptide on APC Class II MHC.
b. CTLA-4 to APC B7.
Cytoplasmic signals generated in response to antigen binding and co-stimulatory signals to Tc cells include all of the following EXCEPT
a. activation of transcription factors that upregulate synthesis of IL-2.
b. aggregation of TCR and CD8 in the T cell membrane.
c. increased free intracellular Ca++.
d. induction of RAG synthesis.
e. tyrosine kinase binding to the cytoplasmic domains of CD3 and CD8.
d. induction of RAG synthesis.
Th1 cells secrete cytokines which
a. activate macrophages.
b. increase susceptibility to allergic reaction
c. inhibit macrophage secretion of inflammatory cytokines
d. stimulate B cells to secrete neutralizing antibodies
e. stimulate proliferation of Th2 cells
a. activate macrophages.
A T cell which binds antigen without undergoing a co-stimulatory signal from an APC
a. becomes inactivated.
b. can become a helper cell but not a killer cell.
c. can get a co-stimulatory signal from a different APC
d. dies.
e. divides but doesn’t make effector molecules.
a. becomes inactivated.
Dendritic cells are the best APCs for activating
a. CTL.
b. helper T cells.
c. naïve T cells.
d. Th1 cells.
e. Th2 cells.
c. naïve T cells.
Macrophages normally have low levels of B7 and MHC, but express more after they phagocytose
a. bacterial antigens.
b. peptide antigens.
c. Tc cytokines.
d. Th cytokines.
e. viral antigens.
a. bacterial antigens.
B cells differ from the other professional APC because B cells
a. activate T cells in the secondary lymphoid organs.
b. present exogenous antigen to T cells on Class II MHC.
c. present only peptides from antigens they bind with their membrane Ig.
d. use B7 as their co-stimulatory molecule.
e. None of the above is true.
c. present only peptides from antigens they bind with their membrane Ig.
Once T cells have received antigen plus co-stimulatory signals, they divide in response to IL-2 secreted by
a. B cells.
b. dendritic cells.
c. macrophages.
d. themselves.
e. whichever APC activated them.
d. themselves.
The a chain of the IL-2 receptor
a. causes the receptor to associate with TCR in the T cell membrane.
b. changes the specificity of the receptor to bind IFNg.
c. increases the affinity of the receptor for IL-2.
d. increases the signal transduction ITAMs of the receptor.
e. All of the above are true.
c. increases the affinity of the receptor for IL-2.
It takes ________________ after antigen contact before T cells are armed effector cells.
a. 5 minutes.
b. 30 minutes.
c. 24 hours.
d. 4-5 days.
e. 7-10 days.
d. 4-5 days.
Armed effector T cells differ from naïve T cells in that effector cells
a. are not antigen-specific.
b. do not need to bind co-stimulatory molecules.
c. do not need to bind peptide plus MHC.
d. do not use CAMs to bind other cells.
e. have CD28 instead of CTLA-4 to bind B7.
b. do not need to bind co-stimulatory molecules.
The effector molecules of cytotoxic T cells do NOT include
a. Fas.
b. granzymes.
c. IFNg.
d. perforin.
e. TNFb.
a. Fas.
Interferons
a. activate B cells to make virus-specific antibodies.
b. are Th2 cytokines.
c. are virus proteins that interfere with activation of cytotoxic T cells.
d. interfere with virus entry into host cells.
e. inhibit virus replication by infected cells.
e. inhibit virus replication by infected cells.
The ability of a cytokine to change gene expression in the target cell is influenced by all of the following EXCEPT
a. presence of high-affinity receptors on the target cell.
b. presence of soluble cytokine receptors.
c. proximity of the producing and target cells.
d. rate of transport of cytokine-receptor complexes into the cytoplasm.
e. simultaneous production of another cytokine whose receptor uses the same signal transducing subunit.
d. rate of transport of cytokine-receptor complexes into the cytoplasm.
IL-1 is produced by macrophages and acts on the hypothalamus to induce fever. This is an example of ____ cytokine action.
a. autocrine.
b. endocrine.
c. paracrine.
d. pleiotropic.
e. synergistic.
b. endocrine.
CD40 on macrophages binding to CD40L on Th1 cells signals the macrophages to
a. die.
b. kill cytoplasmic viruses.
c. phagocytose the Th1 cells.
d. respond to IFNg by expressing more membrane MHC.
e. secrete IL-2.
d. respond to IFNg by expressing more membrane MHC.
Activated CTL can regulate immune responses by signaling activated lymphocytes to undergo
a. apoptosis.
b. clonal deletion.
c. clonal proliferation.
d. cytotoxicity.
e. somatic hypermutation.
a. apoptosis.
Cellular immunity includes all of the following except
a. activated macrophages killing phagocytosed bacteria.
b. CD8 T cells inducing apoptosis using Fas-FasL binding.
c. complement-mediated lysis of bacterial cells.
d. MHC-restricted cytotoxic T cells killing virus-infected cells.
e. NK cells performing natural killing of tumor cells.
c. complement-mediated lysis of bacterial cells.
CTL binding and destruction of target cells depends on
a. a co-stimulatory signal from the target cell.
b. antigen presentation on the surface of the target cell.
c. lack of a negative signal from MHC to prevent cytotoxicity.
d. presence of virus proteins in the membrane of the target cell.
e. secretion of cytokines by the infected cell to attract CTL.
b. antigen presentation on the surface of the target cell.
