Immune Systems

Question 1

Describe the action 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 required by bacteria for growth, thereby inhibiting bacterial growth

Question 3

The innate immune system is comprised of soluble and cellular parts. Give examples of soluble components of the innate immune system.

Answer 3

antibacterial factors (lysozyme, lactoferrin)
complement system

Question 4

Which is the main cell involved in the innate immune system?

Answer 4

Phagocytes

Question 5

What are the three pathways by which the complement system can be activated?

Answer 5

Classical pathway: antigen:antibody complex
MB-lectin pathway
Alternative pathway: pathogen surfaces

Question 6

Which protein do the three complement pathways converge on?

Answer 6

C3

Question 7

The complement cascade results in the formation of which protein responsible for lysis of the microbe?

Answer 7

Membrane attack complex

Question 8

What are the three functions of the complement system?

Answer 8

Recruitment of inflammatory cells
opsonisation of pathogens
killing of pathogens

Question 9

From which cell are macrophages derived?

Answer 9

monocytes

Question 10

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

Answer 10

TNF-alpha

Question 11

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

Answer 11

IL-10

Question 12

Which cell is the most predominant WBC?

Answer 12

Neutrophil

Question 13

The remnants of which WBC make up the majority of pus?

Answer 13

neutrophils

Question 14

Define degranulation.

Answer 14

The extracellular release of toxic granules

Question 15

Which WBCs has a major pathological role in allergy?

Answer 15

Eosinophils and basophils (mast cells)

Question 16

Which type of WBC classically responds to parasites?

Answer 16

Eosinophil

Question 17

To what type of T cell do dendritic cells present?

Answer 17

CD4+ T cells

Question 18

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

Answer 18

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

Question 19

Describe the structure of an antibody.

Answer 19

2 light, 2 heavy chains
y shaped
Fab antibody binding region (variable)
Fc region binds to receptors on phagocytes / activates complement

Question 20

Which cells are responsible for humoral immunity?

Answer 20

B cells

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 involved in the primary immune response?

Answer 22

IgM

Question 23

In the later stages of an immune response more specific IgG antibodies take over from IgM antibodies. What is the term used to describe this phenomenon?

Answer 23

Isotype switching

Question 24

Which type of antibody is predominantly involved in the secondary immune response

Answer 24

IgG

Question 25

Which type of antibody has a high affinity for binding to mast cells and therefore has a role in allergy?

Answer 25

IgE

Question 26

Where can IgA antibodies primarily be found?

Answer 26

Secretions and lining epithelial surfaces

Question 27

The primary immune response has a larger peak response than the secondary immune response. T/F?

Answer 27

False - the opposite is true

Question 28

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

Answer 28

B cells - bone marrow | T cells - thymus

Question 29

Where are lymphocytes produced?

Answer 29

Bone marrow

Question 30

Which interleukin is secreted by regulatory T cells to dampen down an immune response?

Answer 30

IL-10

Question 31

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

Answer 31

The spleen

Question 32

What are the primary organs of the immune system?

Answer 32

Bone marrow | Thymus

Question 33

What are the secondary organs of the immune system?

Answer 33

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

Question 34

If a person is infection again with the same pathogen a secondary immune response occurs. In this case, how would the frequency and activation threshold of these lymphocytes differ from lymphocytes in a primary response?

Answer 34

higher frequency of memory b and T cells | lower threshold for their activation

Question 35

In a secondary immune response what is the function of preformed IgA?

Answer 35

Prevent pathogen binding

Question 36

In a secondary immune response what is the function of preformed IgG?

Answer 36

Opsonise pathogen for phagocytosis

Question 37

Which antibody type can cross the placenta?

Answer 37

IgG