Immunology

Question 1

What is IgG?

Answer 1

MONOMER
Most abundant isotype in blood serum. It enhances phagocytosis of bacteria and viruses and fixes complement and passes to the foetal circulation.

Question 2

What is IgA?

Answer 2

MONOMER/ DIMER
(found in tissue fluid only!)
is the most predominant immunoglobulin in breast milk. It is also found in other secretions of the digestive, respiratory and urogenital tract systems. It is the most commonly produced immunoglobulin in the body.

Question 3

What is IgM?

Answer 3

PENTAMER
It is the first immunoglobulin to be secreted in response to an infection. It fixes complement but does not pass on to the foetal circulation.

Question 4

What is IgD?

Answer 4

MONOMER

Role in the immune system is largely unknown. It is involved in the activation of B cells.

Question 5

What is IgE?

Answer 5

MONOMER

It mediates Type I Hypersensitivity reactions. Provides immunity to parasites such as helminths.

Question 6

What are PAMPs?

Answer 6

Pathogen Associated Molecular Patterns.

They are ligands expressed on the surface of pathogens which allow them to be detected by immune cells.

PAMPs have the ability to activate: macrophages, Mast cells and NK cells

Question 7

What are PRRs?

Answer 7

Pattern Recognition Receptors.

Found on innate immune cells that are receptors for PAMPs found on pathogens.

Question 8

What is a Neutrophil?

Answer 8

Primary phagocytic cell in acute inflammation. It is the most common type of white blood cell and has a multi-lobbed nucleus (4 lobes).

Question 9

What is a Basophil?

Answer 9

releases histamine during an allergic reaction. It expresses IgE receptors on the cell surface and has a bi-lobbed nucleus (2 lobes).

Question 10

What is a Mast Cell?

Answer 10

present in tissues and are similar in function to basophils but derived from different cell lines. Releases histamine during an allergic reaction.

Question 11

What is a Eosinophil?

Answer 11

defends the body against protozoan and helminthic infections. They have a bi-lobbed nucleus (2 lobes).

Question 12

What is a Monocyte?

Answer 12

differentiate in macrophages. They are kidney shaped.

Question 13

What is a Macrophage?

Answer 13

involved in phagocytosis of cellular debris and pathogens. They act as an antigen presenting cell.

Question 14

What is a Natural Killer Cell?

Answer 14

they induce apoptosis in virally infected and tumour cells.

Question 15

What is a Dendritic Cell?

Answer 15

act as an antigen presenting cell for T cells,

Question 16

What are Helper T cells?

Answer 16

are involved in the cell mediated immune response. They recognise antigens presented by MHC Class II molecules and express CD4.

Question 17

What are Cytotoxic T cells?

Answer 17

are involved in the cell mediated immune response. They recognise antigens presented by MHC Class I molecules and express CD8. They induce apoptosis in virally infected and tumour cells.

Question 18

What are B cells?

Answer 18

is a major cell of the humoral immune response. they act as an antigen presenting cell and mediates hyper acute organ rejection.

Question 19

What is Opsonisation?

Answer 19

the coating of pathogens by humeral factors (opsonins) to facilitate phagocytosis.
It is mediated by special Fc receptors that bind specifically to the constant region of the IgY (gamma) heavy chain of IgG.
Examples include: C3b, CRP, IgG/ IgM.

Question 20

What is Neutralisation?

Answer 20

is the ability of antibodies to block the site on bacteria or viruses that they use to enter their target cell.

Question 21

What are Cytokines?

Answer 21

are a diverse collection of small proteins produced in response to infection, inflammation and tissue damage.

Question 22

Describe some cytokines and their functions?

Answer 22

1. Interferons: anti-viral activity.
2. TNF-alpha: a pro-inflammatory cytokine.
3. Chemokines: control and direct cell migration.
4. Interleukins: various functions.

Question 23

What is Primary Lymphoid Tissue?

Answer 23

site of leukocyte development. Includes the thymus and bone marrow.

Question 24

What is Secondary Lymphoid Tissue?

Answer 24

site where T cells and B cells become activated by antigen. Includes the adenoid tonsils, lymph nodes, spleen, payer’s patch.

Question 25

What is Secondary Lymphoid Tissue?

Answer 25

site where T cells and B cells become activated by antigen. Includes the adenoid tonsils, lymph nodes, spleen, payer’s patch.

Question 26

What is Agglutination?

Answer 26

the action of an antibody when it cross-links multiple antigens and so produces clumps of antigens.

Question 27

What are Monoclonal Antibodies and why are they used?

Answer 27

they are antibodies that are made by identical immune cells that are all clones of a unique parent cell. They are used in therapy to neutralise TNFalpha

Question 28

What are Monoclonal Antibodies and why are they used?

Answer 28

they are antibodies that are made by identical immune cells that are all clones of a unique parent cell. They are used in therapy to neutralise TNFalpha

Question 29

What are NETs?

Answer 29

They are Neutrophil Extracellular Traps?
Activated neutrophils release intracellular structures (NETs) into the extracellular environment. They serve to immobilise pathogens, preventing them from spreading and facilitating their phagocytosis.