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MMD 1229 (Patho) > APP 3 - Système immunitaire adaptatif > Flashcards

APP 3 - Système immunitaire adaptatif Flashcards

(56 cards)

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1
Q

Quel type de molécule CMH sont exprimé sur TOUTES les cellules nucléées?

A

MHC I

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2
Q

CMH-II est exprimé sur quels types de cellules?

A

Cellules présentatrices d’antigène (CPA)

  • Macrophages
  • Cell. dendritiques
  • B-cells
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3
Q

Helper T-cells (CD4) recognize which type of MHC?

A

MHC-II

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4
Q

Cytotoxic T-cells (CD8) recognize which type of MHC?

A

MHC-I

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5
Q

Which type of T-cells can bind on receptors that are present on all nucleated cells?

A

Cytotoxic T-cells

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6
Q

Which type of T-cells are effective against virus-infected cells?

A

Cytotoxic T-cells

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7
Q

Which type of cells are effective ONLY against extracellular pathogens?

A

Helper T-cells

- Because they bind to MHC-II on CPA

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8
Q

Which type of molecules does MHC-I present?

A

Endogenous peptides (ex: viral antigens)

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9
Q

Do CPA also express MHC-I?

A

Yes!

If infected by a virus, they will bind CD8 t-cells

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10
Q

Combinaison des allèles d’HLA (human leukocyte antigen) chez un individu

A

Haplotype HLA

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11
Q

T or F?

MHC molecules are specific for one peptide

A

False

MHC molecules have a broad specificity for peptide binding

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12
Q

T of F?

Each MHC molecules can only present one peptide at a time

A

True

However, a single cell has many MHC molecules and they can present many different peptides from the same pathogen

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13
Q

Can cells express “empty” MHC molecules (which do not present an antigen) on their surface?

A

Only MHC which present a peptide are expressed in a stable manner on cell surface

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14
Q

CD28 receptor

A

Co-receptor on T-cells

- Bind B7 expressed on APC upon pathogen infection

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15
Q

Role of co-activators (CD28 on T-cells)

A
  • Control T-cell migration into tissues

- Amplify activation signal via Signal 2 (to avoid false positives)

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16
Q

B-cell receptor complex (BRC) are composed of

A
  • IgM

- Signal molecules (Ig-alpha and Ig-beta)

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17
Q

CD21 (also known as CR2)

A

B-cell co-receptor

  • Binds C3d (complement protein fragment) often found on pathogen
  • Induces signal 2 (= activation of B-cell)
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18
Q

How do macrophages participate in the humoral response?

A

They bind to pathogens that are opsonized by

  • Ab
  • Complement proteins

Phagocytoses them
Destroys them

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19
Q

How do macrophages contribute to the adaptive cellular immune response?

A

Reciprocal activation between Helper T-cells and macrophages

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20
Q

2 types of dendritic cells

A
  • Cellules dendritiques interdigitées (conventionnelles)

- Cellules dendritiques folliculaires

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21
Q

Which type of dendritic cells activate T lymphocytes?

A

Cellules dendritiques interdigitées

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22
Q

Which type of dendritic cells activate B lymphocytes?

A

Cellules dendritiques folliculaires

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23
Q

Where are Cellules dendritiques interdigitées located?

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A
  • Immature: in epithelium (ex: cellules de Langerhans)

- Mature: dans zones de lymphocytes T (tissus lymphoides)

24
Q

Where are Cellules dendritiques folliculaires located?

Study These Flashcards
A

Rate et ganglions:

dans les centres germinaux des follicules lymphoides

25
Where are T-cells located?
- In circulation | - Rate et ganglions: zones périartériolaire ("pulpe blanche" et interfolliculaire
26
Where are B-cells located?
- In circulation | - Follicule des tissus lymphoides périphériques (ganglions, rate, amygdales, tissus muqueux)
27
Les DC des ganglions lymphatiques captent quel types d'antigènes?
Antigènes solubles | Dans la lymphe
28
Les DC dans la rate captent quel types d'antigènes?
Antigènes solubles | Dans le sang
29
Rôle du chimiokine CCR7
Guider la migration des DC Épithélium --> Vx lymphatiques --> Ganglions lymphatiques (site de rencontre avec T-cells)
30
Quelles cellules expriment le chimiokine CCR7? (pour attirer DC)
- cellules épithéliales des vx lymphatiques - cellules dans la zone des ganglions lymphatiques - Lymphocytes T naifs
31
Pourquoi les DC migrent vers la rate, les ganglions, tissus lymphoides?
Car plus grande concentration de T-cells à ces endroits = plus grande chance de rencontrer T-cell avec le bon récepteur
32
Les macrophages activent quels lymphocytes?
Lymphocytes T
33
Comment les macrophages activent les T-cells?
En présentant antigènes sur leurs MHC | et en sécrétant des cytokines (IL-6, IL-12, IL-23)
34
Quel type de protéines sont présentées sur les MHC-I ?
Antigènes cytoplasmiques (produits par virus)
35
Naive B-cells produce which type of antibodies?
- IgM+ | - IgD+
36
Production of functionally different Ab, all with the same specificity, relies on which process?
Heavy-chain class (isotype) switching
37
What does the T-cell receptor (TCR) recognize on APC?
Antigen-MHC complex
38
What are CD4 and CD8? (function)
Co-receptors on T-cells | - Function as co-activators along with TCR (signal 1)
39
What does CD4 recognize?
MHC-II molecules
40
What does CD8 recognize?
MHC-I molecules
41
Do CD4 and CD8 play a role as co-stimulators?
No. They contribute to activating Signal 1 along with the TCR.
42
Which molecules on CPAs work as co-stimulators?
B7 (CD80 and CD86) | their expression is up-regulated upon infection
43
Which receptor do CD80 and CD86 on CPAs bind to?
CD28 receptor on T-cells | = signal 2
44
What is the role of adherence molecules on T-cells? (ex: integrines)
Stabilize the interaction between T-cell & CPA (to allow sufficient stimulation to occur to activate T-cell)
45
Quel est le rôle du ligand CD40 (CD40L) sur les lymphocytes T?
Lier récepteur CD40 sur les CPA - Stimulate APC expression of B7 + cytokine production = indirectement favoriser la différenciation des T-cells
46
Pourquoi faut-il ajouter un adjuvant dans certains vaccins protéiques?
AG protéines: pas toujours suffisants pour déclencher réponses immunitaires dépendantes des T-cells (ce qui est nécessaire pour générer des cellules mémoires) Adjuvant: induit l'expression de molécules de co-stimulation sur les CPA (ex: B7)
47
What are the 2 primary lymphoid organs?
- Thymus (for T-cell development) | - Bone marrow (for B-cell development)
48
Name some secondary lymphoid organs
- Spleen (rate) | - Lymph nodes (ganglions)
49
T or F: | DC can phagocytose infected cells, and then present antigen peptides from these cells on their MHC-I
True! This is especially useful with infected cells that cannot display antigens (ex: RBC)
50
Where do T-cells undergo (+) and (-) selection?
In the thymus
51
Negative selection of T-cells
If TCR binds to self-antigen presented by MHC-I or MHC-II on thymic cell: T-cell will undergo apoptosis
52
Positive selection of T-cells
CD8 and CD4 on T-cells = able to recognize and bind specifically to MHC-I and MHC-II (respectively) Otherwise: T-cell will undergo apoptosis
53
How does a T-cell become a CD4 or CD8 T-cell?
At first, after undergoing both + and - selection in the thymus, T-cells express both CD4 and CD8 co-receptors. It is by CHANCE that they will interact more strongly with either MHC-I (= up-regulate CD8) or MHC-II (= up-regulate CD4). The other type of MHC will be down-regulated.
54
Role of regulatory T-cells
Prevent auto-immune reactions
55
Where are regulatory T-cells found
Corpuscule de Hassal (dans thymus)
56
T or F: T-cells are made in the thymus
False | They are made in the red bone marrow

MMD 1229 (Patho) (9 decks)

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