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Flashcards in Exam Study Deck (29):
1

Name 4 cells which present MHC class I molecules.

T & B cells
Macrophages
Dendritic cells
Granulocytes
(No unnucleated cells)

2

Name 4 cells which present MHC class II molecules.

Dendritic cells
B cells (when upregulated to do so)
Macrophages
T cells (As a rule, they don't always have MHC II but they can)

3

B Lymphocytes: ORIGIN

Bone Marrow
(In foetus = liver)

4

B Lymphocytes: DISTINCTIVE MARKERS

CD19 & CD21

5

B Lymphocytes: FUNCTION

- Secrete antibody
- Secrete cytokines
- Antigen presenting cell
- Bind antigens

6

B Lymphocytes: ANTIGEN RECEPTOR

B Cell Receptor (BCR)
- Membrane bound forms of antibodies (IgM & IgD)
- Structurally different
- BCR looks like an antibody

7

T Lymphocytes: ORIGIN

Bone marrow, mature in thymus

8

T Lymphocytes: MAJOR FUNCTIONS

- Recognise antigen in context of MHC Class I & II
- Secretion of cytokines

9

T Lymphocytes: TWO DISTINCT POPULATIONS

- T helper cells = CD4+ (MHC II Restricted) Function is to secrete cytokines.
- T cytotoxic cells = CD8+ (MHC I Restricted) Function is cytotoxic death of infected cell.

10

T Lymphocytes: ANTIGEN RECEPTOR

T Cell Receptor (TCR)
- Associated with CD3 complex

11

Compare MHC Class I and MHC Class II

MHC Class I:
- On most nucleated cells
- Endogenous Antigens
- Present to T Cytotoxic cells

MHC Class II:
- On antigen presenting cells
- Exogenous (foreign) Antigens
- Present to T Helper cells.

12

Neutrophils: % IN BLOOD

40%-75% of WBCs

13

Neutrophils: MAIN FUNCTION

Phagocytosis (Janitor)

14

Neutrophils: 2 TYPES OF GRANULES

Primary: Lysosomes
Secondary: Lactoferrin, Collagenase

15

Eosinophils: % IN BLOOD

1%-6% of WBCs

16

Eosinophils: FUNCTION

Parasite infection (Eg. Malaria)
Allergy

17

Eosinophils: MEDIATES CYTOTOXICITY VIA RECEPTORS

C3b (complement cascade: opsonisation-phagocytosis)
Some proteins are produced by eosinophils too.

18

Basophils/Mast Cells: ORIGIN

Basophils are similar to mast cells.
- Mast cells, final maturation is in tissue and found in tissue.
- Basophils final maturation is in bone marrow and they are found in the blood.

19

Basophils/Mast Cells: RECEPTOR

IgE receptor for its role in immediate hypersensitivity reactions.

20

Basophils/Mast Cells: FUNCTION

Mediators from granules provoke inflammation
- Histamine, serotonin and heparin production/release
- Slow reactive substance of anaphylaxis
- Eosinophil chemotactic factor of anaphylaxis

21

SPLEEN FUNCTION

Filters blood, traps blood-borne antigens. Activation of T and B cells

22

LYMPH NODE FUNCTION

Filters antigens.

23

Two examples of proinflammatory cytokines

IL-1 and IL-18. Important markers. Levels go up in certain conditions that go on for a long time.

24

Immunoglobulin G (IgG)

- About 80% of total serum Igs
- Can cross placenta
- Only has one Y shape (monomer)
- Complement fixation
- Can act as an opsonin

Subclasses: IgG1, IgG2, IgG3, IgG4

25

Immunoglobulin M (IgM)

- 5-10% of total serum Igs
- It's a pentamer of 5 monomers bound together by J chain.
- Great at agglutination.

26

Immunoglobulin A (IgA)

- 10-15% of total serum Igs
- Monomer or two monomer units = dimer
- Secreted immunoglobulin so is associated with mucosal surfaces.

27

Immunoglobulin E (IgE)

- Very low in concentration
- Monomer
- Role in hypersensitivity (allergies), and parasitic infections
- Induces mast cell degranulation
- ADCC

28

Immunoglobulin D (IgD)

- 0.2% of total serum Igs
- Don't know a lot about
- Important membrane bound antibody that functions as a B cell receptor.
- Role in certain function of B cells

29

What is another name for Mature B Cell?

Naive B Cell