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All of the following are correctly matched except _____.
a.TH1: T-bet
b.Treg: FoxP3
c.IL-12: dendritic cells
d.TH17: ROR T
e.TH2: Bcl6.
Which of the following statements regarding positive selection is correct?
a.All subsets of developing T cells undergo positive selection before export to the
peripheral circulation.
b.T-cell receptor editing is linked to the process of positive selection.
c.Positive selection results in the production of T cells bearing T-cell receptors that have
the capacity to interact with all allotypes of MHC class I and class II molecules, and not
just those of the individual.
d.Positive selection ensures that autoreactive T cells are rendered non-responsive.
e.If there is a genetic defect in AIRE, then T-cell development is arrested as positive
selection commences.
_____ results from alloreactions mediated by donor T cells in the graft subsequent to
hematopoietic stem-cell transplantation.
a.Acute rejection
b.Chronic rejection
c.Graft-versus-host disease (GVHD)
d.Serum sickness
e.Hyperacute rejection.
The C3 convertase that functions in the lectin pathway of complement activation consists
of _____.
a.C3bBb
b.C3b2a
c.C4b2a
d.C4b2b
e.C3b2Bb.
All of the following are released immediately by mast cells after cross-linking
except _____.
a.heparin
b.eicosanoids
c.neutral proteases
d.histamine
e.TNF .
In reference to the interaction between T-cell receptors and their corresponding ligands,
which of the following statements is correct?
a.The organization of the T-cell receptor antigen-binding site is distinct from the
antigen-binding site of immunoglobulins.
b.The orientation between T-cell receptors and MHC class I molecules is different from
that of MHC class II molecules.
c.The CDR3 loops of the T-cell receptor and chains form the periphery of the binding
site making contact with the helices of the MHC molecule.
d.The most variable part of the T-cell receptor is composed of the CD3 loops of both the
and chains.
e.All of the above statements are correct.
The direct pathway of allorecognition involves interaction of _____, whereas the indirect
pathway of alloreaction involves interaction of _____.
a.donor T cells with allogeneic HLA molecule on recipient dendritic cells; recipient T cells
with allogeneic HLA molecules on donor dendritic cells
b.recipient T cells with allogeneic HLA molecules on donor dendritic cells; donor T cells
with allogeneic HLA molecule on recipient dendritic cells
c.recipient T cells with allogeneic HLA molecules on donor dendritic cells; recipient T
cells with peptides of allogeneic HLA molecules on recipient dendritic cells
d.recipient T cells with peptides of allogeneic HLA molecules on recipient dendritic cells;
donor T cells with peptides of allogeneic HLA molecules on donor dendritic cells.
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 chain) and secrete pro-inflammatory
cytokines such as IFN- .
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- and suppress effector T-cell function.
During an infection, _____ are mobilized in large numbers from the bone marrow.
a.dendritic cells
b.memory cells
c.macrophages
d.neutrophils
e.B cells.
_____ is not an opsonin.
a.Mannose-binding lectin
b.IFN-\alpha
c.C-reactive protein
d.surfactant protein-A (SP-A)
e.surfactant protein-D (SP-D).
Peptides that bind to a particular MHC isoform usually have either the same or chemically
similar amino acids at two to three key positions that hold the peptide tightly in the
peptide-binding groove of the MHC molecule. These amino acids are called _____ and the
combination of these key residues is known as its _____.
a.alleles; allotypes
b.anchor residues; peptide-binding motif
c.allotype; haplotypes
d.invariant chains; haplotypes
e.restriction residues; MHC allotype.
Reasons complicating the development of vaccines to combat chronic diseases include
_____. (Select all that apply.)
a.evasion of the host's immune system by the pathogen
b.the polymorphic diversity of MHC class I and class II molecules
c.the generation of inappropriate immune responses that do not eradicate the pathogen
d.survival of the infectious agent for long periods inside the host
e.high mutation rates in the pathogen.
Which of the following is the soluble form of C3 convertase of the alternative pathway of
complement activation?
a.iC3
b.iC3b
c.C3b
d.iC3Bb
e.C3bBb.
