Lecture 1 - Cells of the Immune System Flashcards Preview

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Flashcards in Lecture 1 - Cells of the Immune System Deck (42):
1

What do HSC niches consist of?

What is the importance of niches?

1. Osteoblasts

2. Sinusoidal Endothelial Cells (blood from bone marrow)

3. Stromal Cells

HSC's would die without niches

- attracted via signal gradients

2

Why is it important to have a constant supply of Immune Cells (HSC)?

HSCs are multi-potent, self-renewing sources of white blood cells, red blood cells & platelets

The bone marrow provides structural & molecular support for stem cell renewal & differentiation

3

What cells provide support and growth factors for HSC maintenance?

Stromal Cells

4

What happens to HSC's If they don't return to circulation?

"Mobilized" to differentiate into immune cells
- thus replenish WBC's, RBC's, or platelets
- especially during stressful periods

5

What cells are of common myeloid origin? (2, 5)

RBC:
1. Thrombocytes
2. Erythrocytes

WBC:
1. Mast cells
2. Basophil
3. Neutrophil
4. Eosinophil
5. Monocyte
- Dendritic
-Macrophages

6

What cells are common lymphoid progenitors?

1. Natural Killer cells

Lymphocytes:
2. B Cell --> plasma cell

3. T cell
- helper
-killer

7

What does differentiation into Myeloid or Lymphoid Cells depend on?

Stimulating Growth Factors & Cytokines

- important research tools to study immune cells
- therapeutic tools for patients

Ex: G-CSF to stimulate Neutrophils!

8

How do antigens from sites of infection reach lymph nodes?

VIA LYMPHATICS

9

Where does the thoracic duct drain into?

Left Subclavian Vein

10

Which of the following are specific to ONE pathogen and response results in immunological memory & protective immunity?

1. Innate
2. Adaptive

ADAPTIVE

11

What cells comprise most of the INNATE immune cells and function as the first line of defense, and responsible for carrying and presenting microbes?

Myeloid White Blood Cells!

12

Describe the following for Neutrophils:

1. Activated Function
2. Structure

1. Activated Function
- phagocytosis and activation of bactericidal mechanisms

2. Structure
- 3-4 nuclear lobes
- AKA PMNs (polymorphonuclear neutrophilic leukocytes)
- Light pink H& E staining granules ELECTRON DENSE

13

Both Phagocytes & neutrophils form what when they bind the pathogen and internalize it?

Describe the next 4 steps

1. PHAGOSOME

2. Phagosome is acidified

3. Granules called lysosomes fuse with phagosome

4. Phagolysosome formed

5. Enzymes & Other antimicrobial substances released & pathogen is destroyed

14

What can neutrophil granules also function as besides forming phagolysosome?

DEGRANULATE other antimicrobial substances

1. Primary Granules
- direct/toxic activity

2. Secondary Granules
(specific)
- free radical formation using oxygen and enzymes

15

What comprises 70% of the WBC's in the body?

Where are they normally found?

Where do they migrate during infection?

Life span?

Besides phagocytosis, what else can they participate in?

NEUTROPHILS!

1. Circulating blood, not in tissues (enter during infection)

2. Migrate from blood to TISSUES

3. Short - lived, die after 1 round of phagocytosis

4. Participate in EXTRACELLULAR PATHOGEN killing

16

How do neutrophils effectively immobile EXTRACELLULAR pathogens?

NETS!

- neutrophil extracellular traps

17

What is green sputum a sign of?

Dead Neutrophils

18

Describe the following for macrophages:


1. Activated Functions (2)
2. Structure

1. Phagocytosis & activation of Bactericidal Mechanisms

2. ANTIGEN PRESENTATION!
-generate an antibody

1. Large cells w/ eccentrically placed, vesicular nuclei

2. Many LYSOSOMES in macrophages/monocytes

19

What two cells have the best antibody generation?

Dendritic and Macrophages

(monocytes)

20

How are monocytes Different from macrophages?

Monocytes are mononuclear cells in blood, not usually in tissues (macrophages are in tissues and first to recognize a breech via their receptors)

21

The following is a description of which cell?

1. Located in tissues
2. First to recognize breech
3. Key Mediators of Systemic Inflammation
4. Work Horses of the ADAPTIVE Immune Response
5. SCAVENGERS "pick up debris" so the body doesn't generate another response

Macrophages

22

The following is a description of which type of cells?

1. Circulating mononuclear cells (in blood, not in tissues usually)
2. Continuously patrolling & replenish tissue macrophages & dendritic cells
3. Upregulated & recruited to sites of infection

MONOCYTES

23

What important cell recognizes many conserved microbial patterns via TLR, Mannose, or other receptors?

Macrophages

24

What cells mediate inflammation due to

1. Bacteria in tissue
2. Bacteria in Blood

MACROPHAGES

25

Describe the following for Dendritic Cells:


1. Activated Functions (2)
2. Structure

1. Antigen Uptake into peripheral sites
2. ANTIGEN PRESENTATIOn ( like macrophages)

1. Long finger like processes to increase surface area for antigen display

- found under most surface epithelia & solid organs

26

What are the key roles of Dendritic Monocytes? (3)

1. Initiate Adaptive Immunity

2. Antigen presentation to naive T-Cells

3. Signal T-cells to proliferate & Attack

- differentiation of naive T-cells to effector T cells

27

Where do Dendritic Cells migrate to present the antigen?

Travel through Lymphatics to Lymph nodes

- Tcells enter endothelial cells & find match on dendritic cells

- T - cells activate

28

Describe the following for Eosinophils:


1. Activated Functions (2)
2. Structure

1. Killing of ANTIBODY COATED parasites


Structure:
1. Bi-lobed nucleus
2. basic granules that stain BRIGHT PINK

29

What 4 major substances are released from Activated Eosinophils?

Which of these triggers mast cell histamine release?

Which causes smooth muscle contraction & increased vascular permeability?

1. Major Basic Protein
- toxic to parasites/tissues
-trigger MAST CELL HISTAMINE RELEASE

2. Eosinophil Collagenase
- remodels connective tissue matrix (better contact)

3. Leukotrienes
- cause smooth muscle contraction
- increased vascular permeability
-increased mucous secretion

4. Eosonophil Derived Neurotoxin

30

Where are Eosinophils mostly found?
- What do they kill and how
- how do they augment the inflammatory response

What is an important time that they are recruited?

1. Subepithelial Connective Tissue

2. Kills parasites with toxic granule proteins & free radicals

3. Synthesize chemical mediators to augment inflammatory response

** RECRUITED IN ALERGIC REACTIONS**

31

What myeloid derived cells are recruited in allergic reactions?

Eosonophils

- Can help to sustain allergic reactions

Chronic activation in allergy can lead to tissue remodeling

Ex: Chronic Allergic Asthma - damages tissue due to increased Eosinophil Activation

32

Describe the following for Mast Cells:


1. Activated Functions (2)
2. Structure

1. Release of granules containing HISTAMINE and active agents

Structure:
1. Large cells
2. Mono Nuclear
3. Dark Basophilic granules
(highly acidic) --> rich in histamine & heparin

33



Where are mast cells found?
What does activation cause?
What is the main result of activation? (5)

MAST CELL!

1. Vascularized connective tissue beneath epithelial surfaces

2. Activation causes DEGRANULATION

a). LOCAL INCREASE IN BLOOD FLOW

b) increased vascular permeability (by smooth muscle constriction)

c)Increased fluid & antibody accumulation in tissue

d) Extravasation of immune cells

e) Increased flow of antigen in lymph to regional lymph nodes (due to swelling)


34

What are the results of inappropriate Mast Cell activation? (2)

1. Systemic Anaphylaxis - allergen DIRECTLY in blood stream/absorbed from gut

2. Local Activation:
SKIN ONLY
--> allergic urticaria ex: lips(swelling)

35

Describe the following for Basophils Cells:


1. Activated Functions (2)
2. Structure

1. Participates in Immunity Against Paracitic Infection
- participates in allergic responses

Structure:
- 2-3 poorly defined/obscured nuclear lobes

- Dark basophilic granules rich in histamine & heparin (like mast cells!!)


Participates in anti-parasitic & allergic responses with mast cells & eosinophils

36

Which of the following are innate and which are adaptive from the Lymphoid Family of WBCs?

1. Lymphocytes (T & B cells)

2. Natural Killer Cells (NK)

1. Lymphocytes - Adaptive

2. NK = INNATE!

37

Where are T cells and B cells made?

LYMPHOID ORGANS

1. T cell = thymus

2. B cell = Bone marrow

Circulate in the blood & often stop off at Secondary Lymphoid Organs:

Lymph nodes, spleen, mucosal lymphoid tissue

38

Describe the following for Natural Killer Cells:


1. Activated Functions (2)
2. Structure

1. Front line defense:
-cancer cells
- virus cells

Structure:
- large cells
-mononuclear
-distinctive granular cytoplasm

39

What cells prevent a viral infection from "going viral"

Are these receptors variant or invariant? (innate/adaptive?)

What do they release onto the surface of the cell?

What is induced?

1. Natural Killer Cell

2. INVARIANT receptor aka INNATE and not specific for one protein

3. Release Cytotoxic granules onto surface

4. APOPTOSIS!

40

Describe the following for Small Lymphocytes Cells:


1. Activated Functions (2)
2. Structure





Structure:

Naïve circulating lymphocytes are small, mononuclear & transcriptionally quiescent with condensed chromatin & scant cytoplasm

- they become more vesicular once they find a matching antigen

41

Are B cell receptors variant or invariant?

What is the effector form of B cells? What do they produce?

1. variant


-Recognize a specific antigen

-Proliferate & differentiate into plasma cells

2. Plasma Cells
- produce antibodies which bind specific antigen


42

Are the surface T cell receptors similar to B cell?

What type of cells can T cells differentiate into?

1. Yes, VARIANT receptors

2. Cytotoxic T cells
- directly kill infected cells

3. Helper T cells - make antibody & macrophage responses
- does this via various CYTOKINES

can cause:
1. Inflammation
2. activate Macrophages
3. Regulate T & B cell activity