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BBD Bonneau Lec 3/31/2010 @10am
Cell-Mediated Immune Responses I
38
Medical
Professional
04/04/2010

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Term
What are the two processes involved in the destruction of intracellular bugs?
Definition
Phagocytic and Non-Phagocytic
Term
What do the phagocytic cells attack during intracellular bug infestation?
Definition
intracellular bacteria. Fungi. Protozoa.
Term
What do the phagocytic cells attack during extracellular bug infestation?
Definition
Viruses, Ricksettsiae...and some types of protozoa. Done by destroying the cells which harbor the pathogen.
Term
what do you call a cell that has left the thymus and has yet to encounter an antigen?
Definition
Naive T lymphocyte.
Term
what needs to happen when a naive T cell encounters a microbial antigen?
Definition
1) the number of antigen-specific cells needs to increase. 2) Naive T cells become "armed" effector T cells.
Term
which cells present antigen to naive T cells? which of these cells is the strongest activator of naive T cells?
Definition
Macrophages, B cells, and Dendritic Cells (strongest)
Term
what is so special about APCs that they can turn a naive T cell into an effector T cell?
Definition
they express a co-stimulatory molecule known as B7
Term
what happens when activation of a T cell occurs?
Definition
1) cytokines are secreted. 2) Cytokine receptor expression.
Term
what is the first key step in T cell activation?
Definition
Interleukin 2 (cytokine) is secreted and binds to IL-2 receptor.
Term
what is the function of IL-2?
Definition
clonal expansion.
Term
what is "differentiation" in a T cell response?
Definition
develop a phenotype that allows a function such as "effector cells" and "memory cells"
Term
name two Co-Receptor molecules, and what do they do?
Definition
CD4 and CD8. stabilize interaction between T cell receptor and peptide/MHC complex
Term
which class of MHC does CD4 recognize?
Definition
class II
Term
which class of MHC does CD8 recognize?
Definition
Class i
Term
T/F: the CD4/8 recognition of the MHC molecule occurs in the peptide binding cleft.
Definition
False. this cleft is reserved for peptide and MHC class I/II
Term
what is the major function of CD4+ T cells?
Definition
cytokine producing helper cells
Term
what is the major function of CD8+ T cells?
Definition
cytolytic activity
Term
what is the minimum number of T cell receptors needed for antigen recognition?
Definition
at least two. and it could need to hang onto the cell on the order of minutes to hours to days.
Term
T/F: the TCR provides the necessary signaling to activate a T cell.
Definition
False. mediated by different molecules such as a CD3 complex (Gamma, delta, epsilon chains).
Term
what does Muromorab (drug) do?
Definition
it reacts with the epsilon chain of the CD3 complex and blocks it. Thereby blocking the function of T cells and can help reduce acute allograft rejection in transplant patients (its just an immunosuppressant).
Term
what else helps the binding of a TCR with antigen?
Definition
Integrins such as LFA-1
Term
what does LFA-1 bind to?
Definition
ICAM-1 on APCs.
Term
what do chemokines do to LFA-1 affinity and clustering?
Definition
increases them so you get a much tighter bond between T cell and APC, thus provoking T cell activation.
Term
In general, how do integrins help TCR-peptide/MHC interactions?
Definition
increase the number and length of interactions.
Term
what is the first signal in T cell activation?
Definition
the T cell receptor.
Term
what is the second signal in t cell activation?
Definition
co-stimulatory molecules
Term
what are three examples of co-stimulatory molecules?
Definition
B7.1 and B7.2 and CD40
Term
T/F: components of innate immune response can increase expression of B7.1 and B7.2
Definition
tRuE.
Term
What is CD40 again?
Definition
co-stimulatory molecule.
Term
where does CD40 bind?
Definition
binds to CD40L on T cells
Term
what does CD40 do once bound?
Definition
increases expression of B7 and IL-12 secretion (help activate T cells)
Term
what is the defining feature of a professional APC?
Definition
the ability to express co-stimulatory molecules
Term
what is cross-presentation?
Definition
antigen that has been chopped up into peptides in another cell and is presented on dendritic cells
Term
T/F: CD8+ T cells need activation of CD4+ T helper cells to become activated.
Definition
True. because these T helper cells can make cytokines which can help drive activation.
Term
Where does the "near-ness" of CD4+ and CD8+ T cells take place?
Definition
secondary lymphoid tissues.
Term
HIV destroys which T cells?
Definition
CD4+ T helper cells.
Term
why do infected people have defective CD8+ CTL responses?
Definition
The need for CD4+ T cell help to generate CD8+ CTL responses.
Term
what does "CTL" mean?
Definition
Cytotoxic T Leukocyte
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