Immunology

Question 1

Describe the role of lysozyme in the innate immune system.

Answer 1

Breaks down gram positive cell wall

Question 2

Describe the role of lactoferrin in the innate immune system.

Answer 2

Chelates iron which is normally required for bacterial growth

Question 3

The innate immune system is comprised of soluble factors and cellular factors. Give examples of soluble factors

Answer 3

antibacterial factors e.g. lysozyme and lactoferrin

complement system

Question 4

What are the three pathways of the complement system?

Answer 4

classical pathway: antigen:antibody complex
MB-lectin pathway - sugars bind to pathogen surface
Alternative pathway - pathogen surfaces

Question 5

On which protein to the three pathways of the complement system converge?

Answer 5

C3

Question 6

What are the functions of the complement system?

Answer 6

recruitment of inflammatory cells
opsonisation of pathogens
killing of pathogens

Question 7

From which cell are macrophages derived?

Answer 7

Monocytes

Question 8

Macrophages perform tissue specific functions. T/F?

Answer 8

True

Question 9

Type 1 macrophages produce inflammatory cytokines. Give an example of an inflammatory cytokine.

Answer 9

TNF-alpha

Question 10

Type 2 macrophages produce regulatory cytokines. Give an example of a regulatory cytokine.

Answer 10

IL-10

Question 11

Which type of WBC is most predominant?

Answer 11

Neutrophil

Question 12

Which type of WBC makes up the majority of pus?

Answer 12

Neutrophils

Question 13

Define degranulation.

Answer 13

The extracellular release of toxic granules

Question 14

Which type of WBC classically respond to parasites?

Answer 14

Eosinophils

Question 15

Which types of WBC are particularly involved in the pathology of allergy?

Answer 15

Eosinophils and basophils (mast cells)

Question 16

Which type of WBC guards mucosal sites?

Answer 16

Basophils

Question 17

To which type of T cell, do dendritic cells present to in lymph nodes to initiate an adaptive immune response?

Answer 17

CD4+ T cells

Question 18

Activation of T cells by dendritic cells requires two signals. T/F?

Answer 18

True - the MHC complex binding indicating the presence of a foreign substance and the binding of an activating co-signal

Question 19

Which type of lymphocyte is responsible for humoral immunity?

Answer 19

B cell

Question 20

Describe the structure of an antibody.

Answer 20

2 light and 2 heavy chains
Y shaped
Fab variable antibody region
FC constant region bound to receptors on phagocytes and activates complement

Question 21

What are the three functions of antibodies?

Answer 21

opsonise phagocytosis
activate complement
neutralise toxins and pathogen binding sites

Question 22

Which type of antibody is predominantly secreted in the primary immune response?

Answer 22

IgM

Question 23

Which type of antibody is predominantly secreted in the secondary immune response?

Answer 23

IgG

Question 24

What is the term which describes the switch from mainly IgM to mainly IgG antibody during the switch form primary to secondary immune response?

Answer 24

Isotype switching

Question 25

Which type of antibody can cross the placenta?

Answer 25

IgG

Question 26

Which type of antibody is present in secretions and lines epithelial surfaces?

Answer 26

IgA

Question 27

Which type of antibody has a high affinity for mast cells and therefore plays an important role in allergy?

Answer 27

IgE

Question 28

The peak immune response is larger in the primary immune response compared to the secondary response. T/F?

Answer 28

False - the opposite is true

Question 29

Lymphocytes which strongly bind to self-antigens undergo apoptosis. Where does this occur for B and T cells respectively?

Answer 29

B cells - bone marrow | T cells - thymus

Question 30

Where are B and T cells produced?

Answer 30

Bone marrow

Question 31

What are the primary immune organs?

Answer 31

Bone marrow and thymus

Question 32

What are the secondary immune organs?

Answer 32

Spleen Lymph nodes Mucosal associated lymphoid tissue of the bronchial and GI tract

Question 33

Which type of MHC molecule is present on all nucleated cells, binds to CD8+ T cells and presents intracellular antigens?

Answer 33

MHC 1

Question 34

Which type of MHC molecule is present on APCs, binds to CD4+ T cells and presents extracellular antigens?

Answer 34

MHC 2

Question 35

Which interleukin is released by regulatory T cells to dampen down the immune response?

Answer 35

IL-10

Question 36

Which organ of the immune system is particularly important in responding to encapsulated organisms?

Answer 36

The spleen

Question 37

If a person is infected again with the same pathogen, a secondary immune response occurs. What is the function of preformed specific IgA in this case?

Answer 37

Prevents pathogen binding

Question 38

If a person is infected again with the same pathogen, a secondary immune response occurs. What is the function of preformed specific IgG in this case?

Answer 38

Rapidly opsonises pathogen for phagocytosis

Question 39

If a person is infected again with the same pathogen, a secondary immune response occurs. In this case how is the frequency and activation threshold of memory lymphocytes different to in the primary response?

Answer 39

Higher frequency of memory cells | lower threshold for their activation