Lecture 11: Lymphoid Tissues

Question 1

What are primary lymphoid organs?

Answer 1

Where lymphocytes are produced

Question 2

What cells are lymphocytes?

Answer 2

B cells,
T cells
Natural killer (NK) cells

Question 3

Name some primary lymphoid organs

Answer 3

Thymus
Bone marrow
Foetal liver

Question 4

What is the adaptive immune response comprised of?

Answer 4

B and T cells

Question 5

What are the hallmarks of the adaptive immune response?

Answer 5

Specificity - provided by range of T cell and B cell receptors
Memory - rapid expansion in response to 2ndary encounter

Question 6

What are primary lymphoid organs?

Answer 6

Organs where lymphocytes are produced

Question 7

What cells are lymphocytes?

Answer 7

B Cells
T Cells
Natural Killer (NK) cells

Question 8

Name some primary lymphoid organs

Answer 8

Thymus
Bone marrow
Foetal liver

Question 9

B cells and T cells make up what response?

Answer 9

The adaptive immune response

Question 10

What are the hallmarks of adaptive immunity?

Answer 10

Specificity - provided by vast range of unique T cell and B cell receptors
Memory - rapid expansion in response to secondary encounter

Question 11

Bone marrow is the primary site of what?

Answer 11

haematopoiesis

Question 12

What is the definition of repertoire in immunology?

Answer 12

the range of genetically distinct BCRs (B cell receptors) or TCRs (T cell receptors) present in a given host

Question 13

Where is the B cell repertoire generated?

Answer 13

In the bone marrow

Question 14

Where do immature T cells migrate to after leaving the bone marrow?

Answer 14

To the Thymus (above the heart)

Question 15

What is special about double negative T cells?

Answer 15

Don’t show CD4 or CD8 receptors

Question 16

What is the definition of self in immunology?

Answer 16

anything recognised by the immune system as part of your normal molecular make-up

Question 17

What is the definition of non-self in immunology?

Answer 17

anything recognised by the immune system as foreign

Question 18

Outline T cell selection in the Thymus

Answer 18

Stepwise differentiation
Positive selection - can the T cell receptor signal?
Negative selection - does it react against our own body?
Final selection and exit

Question 19

Why is negative selection important?

Answer 19

protects against our autoimmune diseases

Question 20

Define Thymic involution in immunology

Answer 20

Shrinking of thymus with age. Associated with change in structure and a reduced mass

Question 21

What happens to the thymus as we get older?

Answer 21

It declines with age. The cortex decreases whilst fat increases leading to a much reduced output of new T cells

Question 22

What are secondary lymphoid organs?

Answer 22

Where lymphocytes can interact with antigens and other lymphocytes

Question 23

Name some secondary lymphoid organs

Answer 23

Spleen
Lymph nodes
Appendix
Mucosal associated
Lymphoid tissue

Question 24

How are the lymphoid tissue locations around the body connected ?

Answer 24

They are interconnected via the lymphatic system and the blood

Question 25

What is the purpose of lymphoid tissues and their various locations?

Answer 25

To bring cells in close proximity to antigen

Question 26

Describe the structure of lymph nodes.

Answer 26

Distinct T and B cell zones Afferent (in)lymphatic vessels and efferent (out) lymphatic vessels Arterial and venous connections

Question 27

Describe the structure of the spleen.

Answer 27

Distinct T and B cell zones Afferent (in)lymphatic vessels and efferent (out) lymphatic vessels Arterial and venous connections

Question 28

What is beneficial about the epithelial barriers?

Answer 28

First line of defence against infection Physical barrier Extensive lymphatic network

Question 29

What is the definition of germinal centre in immunology?

Answer 29

Anatomically restricted site where B cells undergo mutation and selection to generate high affinity antibodies

Question 30

Describe gut associated lymphoid tissue.

Answer 30

Specialised secondary lymphoid tissues called Peyer’s patches Found below epithelium of ileum of small intestine

Question 31

How often does a naive T cell recirculate?

Answer 31

Once every 24 hours

Question 32

How do T cells get into the lymph nodes?

Answer 32

T cells enter the lymph nodes through high endothelial venules, and move around within the T-cell area, transiently interacting with large numbers of dendritic cells. They finally leave the node via the efferent lymphatic vessels.

Question 33

Define antigen presentation in immunology.

Answer 33

Display of peptides in major histocompatibility complex (MCH) I or II proteins such that the T cell receptor can attempt to bind them.

Question 34

What are dendritic cells?

Answer 34

Antigen-presenting cells of mammalian immune system.

Question 35

What is the main function of dendritic cells?

Answer 35

To process antigen material and present it on the cell surface to the T cells of immune system. Act as messengers between innate and adaptive immune systems

Question 36

Where do dendritic cells migrate to?

Answer 36

To the lymph nodes via afferent lymph vessel

Question 37

What do dendritic cells do when they enter the lymph nodes?

Answer 37

They present antigen to T cells