Immunology 3 - Initiation of Acquired Immune Responses

Question 1

Where do B cells mature?

Answer 1

Bone marrow

Question 2

What cells are responsible for humoral immune responses?

Answer 2

B cells

Question 3

What are “humors”?

Answer 3

Body fluids

Question 4

What do B cells produce?

Answer 4

Antibodies

Question 5

Where do T cells mature?

Answer 5

Thymus

Question 6

What are antibodies?

Answer 6

Proteins that bind to one specific antigen

Question 7

What are antibodies a complex of?

Answer 7

Four polypeptide chains - two light chains and two heavy chains

Question 8

How can antigens cause an adaptive immune response?

Answer 8

Activating B and T cells

Question 9

What are antibodies also known as?

Answer 9

Immunoglobulins

Question 10

What is the part of the antigen that an antibody attaches to called?

Answer 10

Epitope

Question 11

What does BCR stand for?

Answer 11

B cell receptor

Question 12

What are the five classes of antibodies?

Answer 12

IgM, IgG, IgA, IgE, IgD

Question 13

What is the difference between PAMPs and antigens?

Answer 13

There are a limited number of PAMPs, which are common to many different pathogens
Antigens are unique to an individual pathogenic species

Question 14

What is an antigen?

Answer 14

A substance which can cause an adaptive immune response by activating B and T cells

Question 15

What are sites where T and B cells are activated by antigens?

Answer 15

Secondary Lymphoid Tissues

Question 16

Where do inactive T and B cells circulate between?

Answer 16

The blood, secondary lymphoid tissues and lymphatic vessels

Question 17

What class of antibodies is used to bind to B cells’ target antigens?

Answer 17

IgM or IgD

Question 18

What do B cells do once activated?

Answer 18

Multiply and differentiate into plasma cells and memory B cells

Question 19

What do plasma cells do?

Answer 19

Produce and secrete soluble, antigen specific antibodies

Question 20

What are memory B cells?

Answer 20

Long lived cells that continue to circulate around the body

Question 21

What process do naive B and T cells use to enter the lymph nodes?

Answer 21

Transendothelial migration

Question 22

Where do naive T and B cells enter the lymph nodes from?

Answer 22

High endothelial venules (HEV)

Question 23

What does opsonise mean?

Answer 23

To make a cell more susceptible to phagocytosis

Question 24

How does a B cell encounter antigens?

Answer 24

An opsonised antigen travels to the B cell zone

Eventually the right B cell will come and bind to the opsonised antigen

Question 25

Where are B cell zones located?

Answer 25

Lymph nodes

Question 26

What needs to happen for a B cell to become fully activated?

Answer 26

It must receive two signals: An antigen 'Helping' signals

Question 27

What is the other signal a B cell must receive to become activated when the antigen is a protein?

Answer 27

A help signal from a helper T cell

Question 28

What is the other signal a B cell must receive to become activated when the antigen is not a protein?

Answer 28

A PRR binding to a PAMP

Question 29

What must happen for a B cell to become activated when the antigen has repetitive antigenic epitopes?

Answer 29

Multiple BCR and antigens must be engaged

Question 30

What do the daughter cells of B cells form?

Answer 30

A secondary follicle within the B cell zone called the Germinal Centre

Question 31

What antibodies are first produced by short-lived plasma cells?

Answer 31

IgM

Question 32

What affinity are IgM antibodies?

Answer 32

Low

Question 33

What classes of antibodies are produced after IgM

Answer 33

IgG, IgA, IgE

Question 34

What kind of antigens are B cells that secrete IgG antibodies reacting to?

Answer 34

Protein antigens

Question 35

What affinity are IgG antibodies?

Answer 35

High

Question 36

Why does the antibody level have a lag period?

Answer 36

The process of B cells becoming activated, dividing, differentiating and producing antibodies takes time

Question 37

When are the highest levels of antibodies?

Answer 37

7-10 days after infection

Question 38

What two functions do antibodies have, which part of the antigen performs that function, and what is involved?

Answer 38

``` Recognition function - Variable region sites - Binding to antigen Effector function - Heavy chain constant region - Clearance mechanisms to inactivate to eliminate the microbe ```

Question 39

What are the functions of IgM antibodies?

Answer 39

B cell activation Agglutination Complement system activation

Question 40

What is agglutination?

Answer 40

The formation of immune complexes

Question 41

What does the Ig mean in the names of the classes of antibodies?

Answer 41

Immunoglobulin

Question 42

Where is IgM present and why is it there only?

Answer 42

Plasma and secretions | It is too large to enter tissues

Question 43

What is the process of agglutination?

Answer 43

Antibodies cross-links multiple antigens to produce clumps of antigens

Question 44

What is agglutination mediated by?

Answer 44

Specific antigen binding to IgM and IgG antibodies

Question 45

How does agglutination help to eliminate pathogens?

Answer 45

Enhances phagocytosis | Prevents viruses from binding to and infecting host cells (neutralisation)

Question 46

Which classes of antibodies activate the complement system?

Answer 46

IgM | IgG

Question 47

How do antibodies activate the complement system?

Answer 47

Specific antigens bind to IgM and G receptors, inducing a change in conformation in the fc region. This exposes multiple binding sites for C1, the first component of the classical activation pathway

Question 48

What is the fc region of antibodies?

Answer 48

The tail region that interacts with cell surface receptors

Question 49

What are the functions of IgG antibodies? (6)

Answer 49

``` Agglutination Complement system activation Foetal immune protection Neutralisation Opsonisation NK cell activation ```

Question 50

What is the most abundant class of antibody and the dominant type produces during a secondary immune response?

Answer 50

IgG

Question 51

Which class of antibody has the longest half life?

Answer 51

IgG

Question 52

Which antibodies are transported across the plasma into the foetal blood circulation?

Answer 52

IgG

Question 53

What is neutralisation?

Answer 53

The prevention of viruses from binding to and infecting host cells The prevention of microbial toxins from disrupting normal cell function

Question 54

Why is there a window when babies are at high risk of infection?

Answer 54

After birth babies are no longer being given IgG antibodies by the mother so IgG levels decline. Before IgM, G and A levels increase there is a window where the level of antibodies is low

Question 55

What antibody classes cause neutralisation?

Answer 55

IgG | Secretory IgA

Question 56

What is the structure of IgM antibodies?

Answer 56

Pentamers

Question 57

What is opsonisation?

Answer 57

The process of coating pathogens in immune proteins called opsonins to enhance phagocytosis

Question 58

Which class of antibodies are the most effective opsonins?

Answer 58

IgG

Question 59

Which class of antibodies is the most effective activator of NK cells?

Answer 59

IgG

Question 60

What are the functions of NK cells?

Answer 60

Killing of infected host cells | Production of pro-inflammatory mediators

Question 61

What is the function of IgD antibodies?

Answer 61

B cell activation

Question 62

In what form do IgD antibodies activate B cells?

Answer 62

Membrane-bound form

Question 63

What is the second most abundant type of antibody?

Answer 63

IgA

Question 64

What form of IgA antibody is present in serum?

Answer 64

Monometric form

Question 65

What is the function of the monometric form of IgA antibodies?

Answer 65

Neutralisation

Question 66

What are the functions of the dimetric form of IgA antibodies?

Answer 66

Neonatal defence | Neutralisation at mucosal sites

Question 67

Where is the dimetric form of IgA antibodies present?

Answer 67

Secretory fluids

Question 68

What is the shorthand for the IgA antibodies that are found in secretory fluids?

Answer 68

sIgA

Question 69

Where are sIgA antibodies transported into and why?

Answer 69

Colostrum (colostrum and breast milk | To protect the GI tract of neonates

Question 70

What is colostrum?

Answer 70

A form of milk produced by the mammary glands of mammals in late pregnancy

Question 71

What can IgE antibodies trigger?

Answer 71

Allergic responses

Question 72

Which antibody class(es) are involved in neutralisation?

Answer 72

IgM IgG IgA

Question 73

Which antibody class(es) are involved in agglutination?

Answer 73

IgM | IgG

Question 74

Which antibody class(es) are involved in opsonisation?

Answer 74

IgG

Question 75

Which antibody class(es) are involved in complement activation?

Answer 75

IgM | IgG

Question 76

Which antibody class(es) are involved in NK cell activation?

Answer 76

IgG

Question 77

Which antibody class(es) are involved in placental transfer?

Answer 77

IgG

Question 78

Which antibody class(es) are involved in B cell activation?

Answer 78

IgM | IgD

Question 79

Which antibody class(es) are involved in allergic responses?

Answer 79

IgE