Lecture 2 - Cells & Tissues of the Immune System I Flashcards Preview

MIIM30002 - Principles of Immunology > Lecture 2 - Cells & Tissues of the Immune System I > Flashcards

Flashcards in Lecture 2 - Cells & Tissues of the Immune System I Deck (41):
1

What is a major difference between the lymphatic system and the circulatory system?

Lymphatic is an open circuit, unlike the circulatory system

2

Where do most infections occur? Why is this important?

In the tissue
The tissue fluid is drained into lymphatics, so that the immune system can respond accordingly

3

Describe lymph circulation

1. Tissue fluid drains into lymphatic capillaries
2. Travels through lymphatics
2. Passes through at least one lymph node
3. Draining into subclavian veins

4

Where are T cells produced?

In the bone marrow, but they develop in the thymus

5

Which cell is very important for representing what is happening in the periphery in lymph nodes?

Dendritic cells

6

Describe the structure of a lymph node

• Capsule
• Cortex
• Medulla

• Follicles w/ Germinal centres : B cells
• Paracortex : T cells
• Afferent & efferent lymphatics

7

Where are B cells found in lymph nodes & white pulp?

Follicle, Germinal centre

8

Which organs receive lymph?

Lymph nodes

NOT spleen

9

Which fluids does the spleen receive?

Blood

10

Describe the structure of the spleen

Trabecular artery & vein

Red pulp: Erythrocytes

White pulp:
• PALS: peri-arteriolar lymphatic sheath : T cells
• Germinal centre: B cells
• B cell corona
• Marginal zone
• Perifollicular zone

11

Describe in general the role of the white pulp

Basically like a lymph node; immune response

12

What is the role of the spleen?

Collects up old, dying red blood cells

13

What is the rationale for the naming of eosinophils, basophils and neutrophils?
What is the collective name for these cells?

Eosinophils: stain with eosin
Basophils: stain with a basic dye
Neutrophils: don't stain

These are the granulocytes

14

What is the general function of the granulocytes?

Phagocytosis

15

Describe how neutrophils can kill bacteria

1. Phagocytosis
2. Degranulation
3. NETs

16

Where are neutrophils normally found?

In the blood
They are rarely found in healthy tissue

17

Where are eosinophils found?

Majority found in the tissues (opposite of neutrophils)

18

Describe the function of eosinophils

Releases toxic granules that kill parasites
Two types of granule:
1. Microbicidal:
• Radicals
• Toxic proteins

2. Immunomodulatory
• Leukotrienes
• Protaglandins
• Cytokines

19

What are the two types of granules released by eosinophils?

• Microbicial
• Immunomodulatory

20

What is the function of basophils?
Where are they found?

Granule release:
• Release of histamine from cytoplasmic granules (similar to Mast cells)
• Cytokines

• Role in parasitic infection & allergy (similar to eosinophils)
• Have IgER (similar to Mast cells)
• Role in T cell development

Location
• Recruited out of the blood to the site of infection (similar to neutrophils)
• Are also found in tissue

21

What is the difference between macrophages and monocytes?

Monocytes: in the blood
Macrophages: in the tissues

22

What are some features of Mast cells?

• Contain granules; release of histamine (also cytokines)
• Release in response to Fc receptor cross linking

• Have FcER; binds IgE

23

Where are DCs normally found?

In tissues

24

What is very important about DCs?

They are innate cells, but they activate the adaptive immune system

25

What is the function of NKs?
Be specific!

Kill cells through toxic granule release that are missing 'self' components on surface

Contents of granule:
• Perforin
• Granzymes

26

What is the differentiation between NKs and CTLs?

NKs do not have T cell receptors, which which they can recognise specific cells

NKs only kills cells that are recognised as generically expressing non-self components

27

How many amino acids in an epitope?

8

28

What are the functions of antibodies?

• Neutralisation
• Opsonisation
• Complement activation
• Cell mediated immunity (ADCC)

29

What are the important organs of the immune system?

• Bone marrow
• Thymus
• Spleen
• Lymph nodes
• Tonsils

30

Where is the thymus?

In the chest at the base of the neck
Sitting in from of the thyroid cartilage of the larynx

31

What are the two progenitor cells in the bone marrow, and what do they give rise to respectively?

Myeloid progenitor: innate cells + erythrocytes
Lymphoid progenitor: adaptive cells (+ NKs)

32

What are the stem cells in the bone marrow?

Haematopoetic stem cells

33

Describe phagocytosis

1. Pseudopods extend out around the bacterium
2. Phagosome forms
3. Lysosome fuses with the phagosome
4. Degredation of phagolysosome contents

34

Describe the most important role of neutrophils

Phagocytosis of invaders in infected tissue

35

How do eosinophils kill invaders?

Release of toxic granules

36

What is in the immunomodulatory granules release by eosinophils?

• Histamine

37

Where are the following cells found:
• Mast cells
• Basophils
• Eosinophils
• Neutrophils

MS: Connective tissue

Basophils: tissue & blood

Eosinophils: tissue

Neutrophils: in circulation

38

What is the effect of histamine?

• Increased vascular permeability
• Vasodilation

39

Where do B cells develop?

They are produced and develop in the bone marrow

40

Which cell type releases histamine?
Which cell type releases it most potently?

• Mast cells (most potent releaser)
• Basophils

NB Eosinophils release immunomodulatory granules containing leukotrienes & prostaglandins etc.

41

Which cell type are basophils quite similar to?

Mast cells