Immuno Test II, Lecture 6 Flashcards

0
Q

Where did the cell mediated immunity term evolve from?

A

The finding that immunity to intracellular pathogens could be transferred to other animals by immune cells from infection-recovered animal.

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1
Q

What is cell mediated immunity?

A

due to the direct action of T cells

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2
Q

How have T cells evolved?

A

To protect us against intracellular microbes (viruses and some bacteria)

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3
Q

What do T cells have to help to mount?

A

A robust Ab-mediated humoral immune responses directed agains extracellular pathogens

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4
Q

What can T cells not do?

A

Cannot directly recognize unprocessed Ags or bind to microbes

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5
Q

How are Ags in host cells broken up?

A

Into…

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6
Q

A

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7
Q

A

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8
Q

Each T cell recognizes only one specific foreign peptide, how does the body over come this?

A

but there is a large TCR repertoire generated in the body

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9
Q

Where are the T cells educated?

A

thymus

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10
Q

T cells are either?

A

selected for survival or eliminated if self reactive

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11
Q

What is the general function of different T cells?

A

each with different functions in the immune response that are dictated by cytokines produced

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12
Q

CD4+ T helper cells recognize?

A

peptide Ags in the context of MHC class II molecules that are expressed by dendritic cells, Mo, and B cells

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13
Q

CD8+ cytotoxic T cells

A

recognize peptides associated with MHC class I molecules

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14
Q

What does the CD4 and CD8 attach to?

A

the non-polymorphic (non variant) part of the MHC class II and MHC class I molecules, respectively.

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15
Q

What needs to happen to T cells in order for them to carry our their function?

A

they need to be activated

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16
Q

What is not sufficient to activate the T cells?

A

recognition of the peptide Ag by the TCR

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17
Q

What are required in addition to recognition?

A

Co-stimulatory molecules, with co receptors involved in signaling events

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18
Q

What does T cells activation lead to?

A

production of IL-2, which controls clonal expansion of specivic T cells

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19
Q

What does IL-2 control?

A

clonal expansion of the specific T cell

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20
Q

What does Th1 do?

A

helps Mo to get rid of intracellular microbes and help the development of cytotoxic T cells to kill virus infected cells

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21
Q

What is IFN gamma produced by?

A

Th1 cells activates Mo

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22
Q

What are Th2 cells involved in?

A

Helping B cells to develop into memory cells and plasma cells that produce antibodies

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23
Q

What is IL-4 produced by?

A

Th2 cells

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24
What is IL-4 important for?
B cell proliferation
25
How is B cell activated?
Self activated, but cannot advance without help from Th cells.
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What do B cells develop into?
memory cells and plasma cells
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plasma cells produce?
antibodies
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What is the TCR of conventional (alpha, beta T cells)?
It is composed of two polypeptide chains, alpha and beta, which have molecular wights of 50 and 39 kDa
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What are the genes coding for TCR polypeptide chains?
members of the Ig super family
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What does the T cell receptor complex consist of?
The TCR, the alpha,beta or gamma,epsilon dimer, in association with CD3
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What is CD3?
A signaling complex composed of gamma, epsilon, and delta
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What is a seperate signaling molecule made up of?
...
38
What does CD4 on T cells bind to?
nonpolymorphic region of MHC class II on APCs restricting Th cells to recognizing only peptides presented on MHC class II molecules
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CD8 on cytolytic T cells binds to?
the non polymorphic region of MHC class I, restricting...
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Know what TCR complex looks like
Slide...
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Proteasome genes structure
TAP1, 2
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Look at Detailed map of Human
MHC
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Class I major
HLA-B, C, A
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Class I region minor
HLA G, F, E
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What is the significance of co dominant expression of both parental allels of each MHC gene are expressed?
increases number of different MHC molecules that can presesnt peptides to T cells
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What is the significance of polymorphic genes: many different alleles are in the population.
Ensures that different individuals are able to present and respond to different microbial peptides
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What is the significance of MHC expressing Cell types: Class II: dendrictic cells, macrophages, B cells
CD4+ helper T lymphocytes interact with dendritic cells, macrophages, B lymphocytes
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Class I all nucle
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What are the two classes of polymorphic MHC genes encode human leukocyte ?
Class I and II, that can bind peptides and are thus critical to Ag presentations
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What are class I genes?
HLA-A, -B, -C
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What doe class I genes do?
encode a polymorphic heavy chain which combines with beta2-micro-globulin and is expressed on the surfaces of all nucleated cells
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What does the heavy chains of class I genes have?
a binding groove for peptides to be recognized by T cells
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What are Class II genes?
HLA-D
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What are Class II genes encoded molecules?
(HLA-DP, -DR....
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What is that alpha chain of the class I molecules?
glycosylated (carbohydrate residues are not shown)
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What does the ribbon diagram show??
The stucture of the ex....
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What do the anchor residues on the peptides do?
Bind to residues in the class I and II grooves and vary for different MHC alleles.
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What are MHC class II molecules expressed on?
professional APCs, only B cells, dendritic cells and macrophages
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What are MHC class I molecules expressed on?
all nucleated cells
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What is expression of MHC class I and II modulated by?
cytokines
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What are peptides that bind to class I MHC molecules derived from?
viruses that have infected host cells and move as the complexes to the surfac (endogenous pathway)
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What doe petides that bind to class I MHC bind to?
recgonized bty CD8+ cytotoxic T lymphocytes CTL
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Ags and pathogens taken from the environment primarily present on?
MHC class II molecules to CD4+ helper T cells
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What are professional APCs?
B cells macrophages, dendritic cells... They are strongly expressed on MHC class I and II
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Dendritic cells recognize?
antigens at the gate..
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CD28 does what?
Binds dendritic cell and naive T cells with the costimulator B7