BIOL 5500 Exam 3 QUESTIONS
AND ANSWERS
Antibodies consist of
two identical heavy chains and two identical light chains
Regions of TCRs and BCRs that are particularly variable in their amino acid
sequences are known for
binding to antigen
MHC molecules
are recognized by T cells
Based on your knowledge of MHC I and II, predict which cell type would be MOST
likely not to express detectable MHC I
erythrocytes
-MHC I is present on nucleated cells.
Which of the following cell types would be LEAST likely to express MHC class II?
T cells
What defines an exogenous antigen?
It is generated outside of the cell then taken into the cell by endocytosis
Which most accurately represents the general order of the steps to antigen
presentation?
antigen acquisition, antigen breakdown into peptides, encounter of peptides with MHC
molecules, binding of peptides to MHC molecules, and display of the peptide-loaded
MHC molecules on the cell surface
What defines an endogenous antigen?
it is generated within the cell
,The human MHC locus is one of the most polymorphic regions of the genome.
What does this mean?
There are many different alleles of these genes
Peptide-binding diversity is increased by
both multiple MHC alleles in the population and multiple homologous MHC genes in the
genome
Committed lymphocyte progenitors originate in the
bone marrow
-all blood cells originate in the same anatomical location
What term BEST describes a selection process against those cells whose T-cell
receptors bind too strongly to self-peptide/MHC combinations?
negative selection
-against implies negative
Which of the following molecules would double-negative T cells fail to express?
CD4
Signaling through the pre-TCR occurs as a result of
successful assembly of the pre-TCR
-this signaling does not require ligand binding
In negative selection, cells that receive __________ signal through their antigen
receptors die
a strong
Which of the following represents the EARLIEST stage in T-cell development?
DN
-coreceptors are necessary for positive and negative selection
What happens to autoreactive cells that escape the thymus?
-They negatively regulate other autoreactive cells
-They can be rendered anergic
, -They attack self-tissues
-They require TCR ligation and costimulation to be activated
-not all self antigens are expressed in the thymus
What is currently the BEST explanation for what determines whether a T cell
develops into a CD8+ T cell or a CD4+ T cell?
CD4 or CD8 expression is determined by the strength and duration of the TCR/MHC
interaction
Naïve CD4+ and CD8+ T-cells leave the ___________ and enter circulation
thymus
Which of the following molecules provide costimulatory signals to naïve T cells?
CD28
CD4+ T cells recognize
MHC class II peptides
CD8+ T cells exposed to MHC class I peptides are
cytotoxic T cells
Bonds formed between the T cell and a dendritic cell are relatively weak. Which of
the following help to strengthen this association so that a T cell can see which
antigen is being presented by a dendritic cell?
ICAM-1/LFA-1
Which of the following is required for T-cell activation?
Both antigen-specific TCR binding to MHC peptide and interaction with CD80, CD86, or
ICOS-L
CTLA-4 is a costimulatory receptor on T cells that belongs to the same family as
the CD28 costimulatory receptor. However, CTLA-4 is antagonistic to CD28.
Which of the following could be a functional advantage of CTLA-4 expression
within the immune response?
CTLA-4 limits the immune response of TC and TH cells after an infection has been
cleared
Which of the following treatments would most likely inhibit activation of CD4+ T
cells and have little/no effect on CD8+ T cells?
AND ANSWERS
Antibodies consist of
two identical heavy chains and two identical light chains
Regions of TCRs and BCRs that are particularly variable in their amino acid
sequences are known for
binding to antigen
MHC molecules
are recognized by T cells
Based on your knowledge of MHC I and II, predict which cell type would be MOST
likely not to express detectable MHC I
erythrocytes
-MHC I is present on nucleated cells.
Which of the following cell types would be LEAST likely to express MHC class II?
T cells
What defines an exogenous antigen?
It is generated outside of the cell then taken into the cell by endocytosis
Which most accurately represents the general order of the steps to antigen
presentation?
antigen acquisition, antigen breakdown into peptides, encounter of peptides with MHC
molecules, binding of peptides to MHC molecules, and display of the peptide-loaded
MHC molecules on the cell surface
What defines an endogenous antigen?
it is generated within the cell
,The human MHC locus is one of the most polymorphic regions of the genome.
What does this mean?
There are many different alleles of these genes
Peptide-binding diversity is increased by
both multiple MHC alleles in the population and multiple homologous MHC genes in the
genome
Committed lymphocyte progenitors originate in the
bone marrow
-all blood cells originate in the same anatomical location
What term BEST describes a selection process against those cells whose T-cell
receptors bind too strongly to self-peptide/MHC combinations?
negative selection
-against implies negative
Which of the following molecules would double-negative T cells fail to express?
CD4
Signaling through the pre-TCR occurs as a result of
successful assembly of the pre-TCR
-this signaling does not require ligand binding
In negative selection, cells that receive __________ signal through their antigen
receptors die
a strong
Which of the following represents the EARLIEST stage in T-cell development?
DN
-coreceptors are necessary for positive and negative selection
What happens to autoreactive cells that escape the thymus?
-They negatively regulate other autoreactive cells
-They can be rendered anergic
, -They attack self-tissues
-They require TCR ligation and costimulation to be activated
-not all self antigens are expressed in the thymus
What is currently the BEST explanation for what determines whether a T cell
develops into a CD8+ T cell or a CD4+ T cell?
CD4 or CD8 expression is determined by the strength and duration of the TCR/MHC
interaction
Naïve CD4+ and CD8+ T-cells leave the ___________ and enter circulation
thymus
Which of the following molecules provide costimulatory signals to naïve T cells?
CD28
CD4+ T cells recognize
MHC class II peptides
CD8+ T cells exposed to MHC class I peptides are
cytotoxic T cells
Bonds formed between the T cell and a dendritic cell are relatively weak. Which of
the following help to strengthen this association so that a T cell can see which
antigen is being presented by a dendritic cell?
ICAM-1/LFA-1
Which of the following is required for T-cell activation?
Both antigen-specific TCR binding to MHC peptide and interaction with CD80, CD86, or
ICOS-L
CTLA-4 is a costimulatory receptor on T cells that belongs to the same family as
the CD28 costimulatory receptor. However, CTLA-4 is antagonistic to CD28.
Which of the following could be a functional advantage of CTLA-4 expression
within the immune response?
CTLA-4 limits the immune response of TC and TH cells after an infection has been
cleared
Which of the following treatments would most likely inhibit activation of CD4+ T
cells and have little/no effect on CD8+ T cells?
