Lecture 1

Question 1

What are the four main types of pathogens? give an example for each

Answer 1

Viruses (SARS-CoV-2, Influenza, HIV, poliovirus)

Bacteria (Staphylococcus aureus, Mycobacterium tuberculosis, Vibrio cholerae)

Fungi (Candida albicans)

Parasites (Trypanosoma, Leishmania, Roundworms, Tapeworms)

Question 2

What do innate immune cells recognise on the pathogens and how?

Answer 2

Recognise PAMPs (Pathogen associated molecular patterns)

Recognised by PRRs (pattern recognition receptors)

Question 3

Give three examples of phagocytosing cells

Answer 3

1. Macrophages
2. Neutrophils
3. Dendritic cells

Question 4

What is the innate immune system?

Answer 4

non-specific, rapid first line of defence

Question 5

Give an example of humoral innate immune response

Answer 5

Complement system

Question 6

Give an example of a cell mediated innate immune response

Answer 6

Neutrophil phagocytosing and destroying pathogen

Question 7

What is the adaptive immune response?

Answer 7

specific and effective against certain pathogen. memory cells form for more rapid response if reinfection occurs.

Question 8

Give an example of humoral adaptive immune response

Answer 8

Clonal selection and clonal expansion of specific B-lymphocyte to secrete antibodies

Question 9

Give an example of a cell mediated adaptive immune response

Answer 9

Cytotoxic T-lymphocytes

Question 10

How are the PRRs of innate immune response encoded?

Answer 10

Germ line encoded (already present from birth)

Question 11

How are BCRs and TCRs of the adaptive immune response encoded?

Answer 11

encoded by genes created during ransom DNA re-arrangements to give variability in receptors.

Question 12

What is clonal selection?

Answer 12

The binding of an antigen to an individual B or T cell that triggers clonal expansion of the cell to produce a population with the same antigen specificity in order to increase the number of cells responding to the pathogen and form memory cells

Question 13

How does the antigen binding to B and T cells differ?

Answer 13

B cells can bind directly to the antigen

Where as T- cells can only bind to an antigen that is being presented to them by an APC

Question 14

What is the difference between MHC I and MHC II molecules?

Answer 14

MHC I is present on the surface of all nucleated cells. requires CD8 co-receptor

MHC II is present only on the surface of antigen presenting cells. Requires CD4 co-receptor

Question 15

True or false: innate immunity has memory?

Answer 15

True, it has some memory in the form of innate lymphoid cells (ILCs) and trained immunity in macrophages - little known about innate memory - most of the memory is in the adaptive immune response.

Question 16

Give some major cell types of the innate immune response

Answer 16

Phagocytes
Innate lymphoid cells (E.g. natural killer cells)
granulocytes (neutrophils, eosinophils, and basophils)
Antigen presenting cells (macrophages, dendritic cells)

Question 17

Give some major cell types of the adaptive immune response

Answer 17

T-cells
B-cells
(activated by APCs)

Question 18

Where do all immune cells develop?

Answer 18

develop in bone marrow from haematopoietic stem cells

Question 19

What are the two main cell lineages of immune cells?

Answer 19

myeloid and lymphoid

Question 20

What are the primary lymphoid organs?

Answer 20

Bone marrow and the Thymus

Question 21

What is different about the maturation of T-cells?

Answer 21

They are produced in the bone marrow and migrate to the thymus as double negative cells - it moves through the cortex and medulla, where it experiences different microenvironments that allow differentiation into single positive cells.

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2861282/

Question 22

What are the secondary lymphoid organs?

Answer 22

spleen and lymph nodes

Question 23

What is the main role of the secondary lymphoid organs?

Answer 23

location for interaction between B and T cells with antigens to become activated, expand in numbers, and differentiate into effector cells.
- lymph nodes are responsible for filtering the lymph
- the spleen filters blood (functions against blood-borne pathogens)

Question 24

What is Mucosa associated lymphoid tissue?

Answer 24

example of another secondary lymphoid organ - it is a large, dispersed and important lymphoid tissue to protect vulnerable mucosal surfaces (gut, lungs, nasal passages)

• where antigen sampling occurs in small intestine and immune responses are initiated
• epithelia overlying (MALT) contain membranous (M) cells which transport antigenic matter across the mucosal membrane to initiate immune responses.

https://pubmed.ncbi.nlm.nih.gov/10381862/

Question 25

how is the lymph node arranged in terms of zones?

Answer 25

B and T cells separated into distinct microenvironments - B cell = cortex - T cell = paracortex

Question 26

How do antigens enter the lymph nodes?

Answer 26

afferent vessel

Question 27

how do naive lymphocytes enter the lymph nodes?

Answer 27

High endothelial venule (HEV)

Question 28

how do lymphocytes exit the lymph nodes?

Answer 28

efferent vessel

Question 29

What are the three main compartments/components of the spleen and the cells they contain?

Answer 29

Red pulp = red blood cells White pulp = white blood cells marginal zone (boarders white pulp) = macrophages and B cells

Question 30

What are cytokines?

Answer 30

small protein messengers that send signals between immune cells and generate a response by signal transductiong

Question 31

Give some responses generated by cytokines?

Answer 31

differentiation, proliferation, apoptosis

Question 32

what are chemokines?

Answer 32

class of chemoattractants that are small protein messengers that send signals with the main effect of causing movement of target towards source.