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Immunology Exam 3 Practice Questions

Immunology Exam 3
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True or False
MHC class I & II are like T and B cell Recptors in that they undergo genetic rearrangement
FALSE
What are 4 primary interactions that take place between the surface of an APC & CD4T
1) Peptide/MHC & TCR
2) MHC Class II and CD4
3)Co-Stimulator Pairs (B7 w/ CD28 & CD152, CD40, CD154)
4)Adhesion Molecules (CD54 w/ CD11a/CD18 & CD58 w/ CD2)
What are the characteristics of an Activated Dendritic Cell?
-Increase expression of B7 on Surface
-Increase expression of MHC class II molecules on the surface (or if infected w/ virus, MHC class I molecules)
-Synthesizes high levels of chemokines (pro-inflammatory cytokines)
What are 3 types of APC's?
-DendriticCells
-Macrophages
-B cells
CD4T cells are activated by which type of antigen?
Exogenous Antigen
What are the functions of Effector T cells?
-Helper T cells produce cytokines that affect many cells
-Cytotoxic T cells kill infected target cells.
An activated T cell produces antibody...True or False
FALSE
MHC class II molecules present to which class of T cells?
CD4T
MHC Class II molecules are present on APC's
True or False
TRUE
MHC Class I presents which type of antigen
Endogenous
Nearlyh all cells present MHC class I molecules...
True or False
TRUE
This cell determines whether or not a developing T cell can bind too tightly to self-antigen in MHC pocket
Thymic Dendritic Cell
T cells have CD40L on surface, which interacts w/ CD40 on the surface of the B cell...
True or False
TRUE
Helper T cells interact w/ MHC class I molecules...
True or False
FALSE
CD4 is found on which type of T cell
Helper T Cell
What does the TCR complex consist of?
-TCR
-CD3 (gamma epsilon epsilon sigma)
-Zeta Chains
RAG 1 and Rag 2 are involved in the generation of a T cell receptor..
True or False
TRUE
T cells that leave the thymus have both CD4 and CD8 on their surface.
True or False
FALSE
Which form of selection ensures that T-cells will bind to MHC?
Positive Selection
Coritcal Thymus Epithelial cells are involved in which form of selection for T-cells?
Positive Selection
The TCR antigen binding is the result of VDJ and VJ rearrangements...
True or False
TRUE
The TCR and BCR are identical in their valence and conformation...
True or False
FALSE
A thymocyte that enters the thymus is double positve...
True or False
FALSE
What makes up a pre-T cell receptor?
-Beta chain and pre T alpha chain
-CD3
-Zeta Chain
Which co-receptor does a helper T cell have?
CD4
Cytotoxic T cell binds to which MHC molecule?
MHC class I
A T cell that directly kills infected targel cells is what kind of T cell?
CytotoxicT Cell
Where do T cells Develop?
Thymus
Erp57, calreticulin & tapasin are invovled in the assembly of which MHC molecule?
MHC class I
To what molecules do Superantigens bind?
Superantigens bind to MHC class II and to one or more Vbeta regions of TCR.
What is the Danger Hypothesis?
States that exposure to foreign antigen induces tissue damage that sends danger signals to provide the secodary signal necessary to generate activated T cells.
What does calnexin do?
Chaperone that binds to partially folded MHC class I and maintains conformation for Beta2-microglobulin to bind.
Where are exogenous antigens processed?
Endosome or phagosome
Exogenous antigens are presented by which MHC molecule?
MHC class II
The peptide binding groove of MHC class II molecules have the capacity to bind to peptide have how many Amino Acids?
12-17
MHC class II molecules present to which class of T cells?
CD4T cells
The peptide binding groove of MHC class I is referred to as _______________?
Closed
The fragments processed in the proteasome are then transported across the membrane of endoplasmic reticulum by ________________.
Transporter proteins TAP-1 and TAP-2
During Endogenous processing, peptides are processed in the ________________.
Proteasome
What is the function of HLA-DM molecule?
Removal of CLIP from the antigen binding pocke of MHC class II and assists in loading peptide into MHC class II pocket.
The invariant chain blocks the antigen binding pocket of which MHC molecule in Endoplasmic Reticulum?
MHC class II
MHC class II molecules are present on APC's and can be induced to be expressed on endothelial cells...
True or False
TRUE
MHC Class I presents which type of Antigen?
Endogenous
The Antigen Binding Pocket of MHC class II is make of which domains?
Alpha 1
Beta 1
Which domains does MHC class II have?
-Alpha 1
-Alpha 2
-Alpha 3
-Beta-microglobulin
Nearly al lcells present MHC class I molecules...
True or False
TRUE
What are 3 genes that encode for MHC class I?
-HLA-A
-HLA-B
-HLA-C
True or False....The immunological synapse is rigid and unchanging?
FALSE
Which transcription factors are activated as a result of intracellular signaling within CD4t cells following stimulation?
-NF-KB
-NF-AT
-AP-I
True or False....Superantigens are not processed like normal antigens?
TRUE
Which subset of helper T cells switches B cell isotypes to IgE and activate eosinophils in response to allergens and parasitic worms?
TH2
The subset of T cells regulates TH1, TH2, and TH17 cells
TREG
__________ make by THI can inhibit TH2 cell generation
IFN-gamma
Activation of a B cell by a T cell dependent antigen allows for isotype switching...true or false?
TRUE
What are the 2 Pathways of Killin by Cytotoxic T cells?
-1st and most frequent is use of cytotoxic granules, released after attachment by exsocytosis
*Major Cytotoxins*
-Perforin polymerizes into transmembrane pores that increase membrane permeability
-Granzymes are serine proteases that pass into the cell and induce apoptosis (preventing lysis and releasing virus)

-2nd pathways uses interaction of CD178 (Fas Ligand) on CD8+ cell with CD95 (Fas) on host cell, using caspase proteolytic enzymes to activate apoptosis of target cells.
A polysaccharide is an example of what type of antigen in B cell activation?
T independed antigen
True or False.....Cytotoxic T cells do not required co-stimulatory signals.
FALSE
What is the co-receptor for the cytotoxic T cell?
CD8