Lecture 2 (Week 1B) - Lymphocyte Formation Flashcards Preview

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Flashcards in Lecture 2 (Week 1B) - Lymphocyte Formation Deck (39):
1

The cells of the immune system work as

an INTEGRATED DEFENSE system to eliminate or control an infectious agent

2

The immune system provides

LONG-LASTING PROTECTIVE IMMUNITY

3

Pathogens target various

compartments of the body
which require different host defense mechanisms for eradication

4

Extracellular host defense mechanisms

blood, lymph, interstitial spaces
• antibodies
• complement
• phagocytosis

epithelial surfaces
• antibodies (IgA)
• antimicrobial peptides

5

Antibodies abbreviation

IgA
Ab

6

Intracellular host defense mechanisms

cytoplasmic
• cytoxic T cells
• NK cells

vesicular
• T cell-dependent macrophage activation

7

Immunogen

anything which elicits an immune response

8

Antigen

anything recognized by a
• B cell receptor (antibody or
• T cell receptor

9

An antigen is a part

of something which our bodes may encounter
• bacteria
• virus
• fungi
• parasite
• food protein
• pollen
etc

10

All immunogens are

all immunogens are antigens
BUT
all antigens are not immunogens

11

Hapten

injected into an animal = no immune response
eg DNP

12

A hapten is

a hapten is a antigen, but it is NOT an immunogen

13

Protein carrier

injected into animal = anti-BSA Ab
eg BSA

14

Hapten-carrier

congugate injected into animal =
anti-BSA Ab
anti-DNP Ab
eg DNP-BSA

15

Epitopes

immunologicallly active parts of an antigen

16

Antibodies (Abs) can bind to

epitopes on antigens

17

The lymphoid system

• primary lymphoid tissue
• secondary lymphoid tissue

18

Primary lymphoid tissue

where lymphocytes are made
• Thymus - T cells
• Bone marrow - B cells and NK cells

19

B of B cell

is for Bursa (the primary lymphoid tissue for B cells in birds)
• NOT FOR BONE-MARROW

20

Bursa

the primary lymphoid tissue for B cells in birds

21

Secondary lymphoid tissue

where immune responses occur
• lymph nodes
• spleen
• tonsils
• Peyer's patches (gut)
• appendix

22

Primary lymphoid tissue size

size is antigen-independent

23

Secondary lymphoid tissue size

size is antigen-dependent
eg secondary lymphoid tissue in the gut

24

Lymphatic vessels

allow fluid to drain from the tissues into lymph nodes
• the lymphatic system is designed to get antigens into lymph nodes, where the antigens can stimlate T cells and B cells

- "draining lymph node"
- afferent lymphatic vessel

25

The lymphatic system is designed to

get antigens into lymph nodes, where the antigens can stimulate T cells and B cells
• "draining lymph node"
• afferent lymphatic vessel

26

T and B cells reside in

different parts of the lymph nodes
• T cells = paracortex
• b cells
• germinal center

27

High Endothelial Venule (HEV)

HEVs are specialized post-capillary venous swellings that allow circulating lymphocytes to leave the blood and enter the lymph nodes

28

The spleen is the lymphoid tissue which

samples antigens in the blood
• splenectomised individuals are more susceptible to blood infections = septicaemia

29

Splenectomised individuals are more susceptible to blood infections = septicaemia

blood infections = septicaemia

30

Splenic structure

white pulp
• primary follicle
• marginal zone
• periarteriolar lymphoid sheath (PALS)

artery and vein

31

In mammals, B cells develop from

stem cells in the bone marrow
• stem cells -->
• Pro-B cells -->
• Pre-B cells -->
• immature B cells
(--> mature naive B cells)

32

B cells become

plasma cells which produce huge amounts of diverse antibodies

33

Plasma cells produce

huge amounts of diverse antibodies

34

T cells recognize antigens using their

T Cell Receptor (TCR)
• αβ TCR
- TCRβ
-TCRα

• γδ TCR
- TCRγ
- TCRδ

35

T cells are generated in

the thymus
( a primary lymphoid tissue)

36

Thymus structure

cortex (outside)
medulla (inner part)

37

The thymic gland ... with ...

involutes with age

38

All T cells develop from

a common bone marrow-derived progenitor in the thymus

39

After eg a serious cut, dendritic cells to go

the draining lymph nodes