Interleukins

Question 1

What do interleukins consist of

Answer 1

33 different constituent members

Question 2

What do interleukins regulate

Answer 2

• Normal and malignant cell growth
• All aspects of immune response
• Regulation of inflammation

Question 3

Interleukin 2 (IL-2)

Answer 3

• Aka T-Cell growth factor
• First T-Cell growth factor to be identified
• Produced exclusively by T-lymphocytes in response to antigen stimulation
• Role in the immune response

Question 4

Structure of IL-2

Answer 4

• Single chain glycoprotein
• Contains 133 amino acids
• Globular structure - consists of 4 a helical structures and no b conformation

Question 5

Function of IL-2

Answer 5

• Acts as a central autocrine growth factor for T cells - magnitude of t cell response dependant on IL-2 production
• growth factor for activated B lymphocytes
• stimulates enhanced antibody production and secretion
• Promotes the growth and differentiation of NK cells to form lymphokine activated killer cells.

Question 6

How was IL-2 produced before recombinant DNA technology?

Answer 6

produced by transformed cell lines - Jurkat leukaemia cell line

Question 7

How is large-scale IL-2 production achieved today?

Answer 7

heterologous expression against and E. coli background

Question 8

Recombinant IL-2 preparation

Answer 8

Tradename: Proleukin
Manufactured by: Chiron

Question 9

how does Proleukin differ from IL-2

Answer 9

non-glycosylated
lacks N-terminal alanine
cys 125 residue has been replaced by a serine

Yet they display same bio activities

Question 10

What is the significance of IL-2 in cancer treatment?

Answer 10

• Experiments in the 1980s showed that lymphocytes incubated with IL-2 could kill a range of cancer cell lines, including melanoma and colon cancer.
• IL-2 stimulated NK cells (LAK) mediate cancer cell destruction.

Question 11

How is IL-2 used to promote tumour regression in cancer patients?

Answer 11

• LAK cells purified from a patient’s blood and activated with IL-2 in vitro
• Reintroduced into the patient along with more IL-2.
• Complete tumour regression in 10% of patients with melanoma or renal cancer
• Partial regression in 10-25% of such patients.

Question 12

What are tumour-infiltrating lymphocytes (TILs)?

Answer 12

• IL-2 stimulated cytotoxic T cells
• Cytotoxic T-lymphocytes that specifically bind to the tumour antigen - tumour-specific cells.
• These cells can be isolated from a tumour biopsy and further activated with IL-2 in vitro.

Question 13

How effective is IL-2 treatment in promoting tumour regression in cancer patients?

Answer 13

• Further activation of TILs with IL-2, followed by reintroduction into the patient along with more IL-2, promotes tumour regression in >50% of treated patients.
• Additional cancer types, such as ovarian and bladder cancer, non-Hodgkin’s lymphoma, and acute myeloid leukemia, have also shown partial responsiveness to IL-2 treatment.

Question 14

What are intracellular pathogens?

Answer 14

microbial pathogens that replicate within host cells.

Question 15

Why are intracellular pathogens difficult to treat?

Answer 15

• They hide within host cells and evade the immune system.
• They can also develop resistance to antibiotics.

Question 16

What are some examples of intracellular pathogens?

Answer 16

• Mycobacterium tuberculosis
• Listeria monocytogenes
• Legionella pneumophila.

Question 17

What type of immune response is raised against intracellular pathogens?

Answer 17

Largely a T-cell response.

Question 18

How might IL-2 be useful in the treatment of intracellular pathogens?

Answer 18

IL-2’s ability to stimulate T-cells renders it useful

Question 19

What medical conditions are caused or exacerbated by the immune system itself?

Answer 19

• Autoimmune diseases
• Tissue/organ transplantation rejection

Question 20

How is selective immunosuppressant activity achieved in idividuals suffering with autoimmune diseases or organ rejection?

Answer 20

By preventing the synthesis or functioning of IL-2

Question 21

example of immunosuppressive for IL-2

Answer 21

Cyclosporin A

• One of the foremost immunosuppresive agents currently in use
• Functions by preventing IL-2 synthesis

Question 22

What are alternative approaches to IL-2 targeted immunosuppression?

Answer 22

• Soluble IL-2 receptor that competes with native receptor for binding of IL-2
• IL-2 varients that retain the ability to bind but fail to initiate signal transduction
• Monoclonal antibodies that block IL-2 binding

Question 23

What are some examples of monoclonal antibodies that are capable of blocking IL-2 binding?

Answer 23

Zenapax and Simulect

Question 24

Interleukin-1 (IL-1)

Answer 24

• also known as lymphocyte-activating factor (LAF)
• endogenous pyrogen
• catabolin

Question 25

Forms of IL-1

Answer 25

two distinct forms: IL-1α and IL-1β.

Question 26

What cells produce IL-1

Answer 26

a wide range of cells, in varying ratios.

Question 27

What is the structure of IL-1α and IL-1β?

Answer 27

* Globular proteins * Composed of 6 strands of antiparallel β pleated sheets. * Only 20% aa sequence identity but both bind to the same receptor & induce similar biological activities.

Question 28

IL-1 biological activities

Answer 28

* Proinflammatory cytokine - promotes synthesis of substances involved in generating inflammatory mediators. * Role in activating B-Lymphocytes * Synthesis of acute-phase proteins in hepatocytes with IL-6 * Acts as co stimulator of haematopietc cell growth/differentiation

Question 29

IL-1 receptor antagonist (IL-1Ra)

Answer 29

* Third IL-1-like protein * binds to IL-1 receptor without triggering an intracellular response

Question 30

Acute-phase proteins (APPs)

Answer 30

an evolutionarily conserved family of proteins produced mainly in the liver in response to infection and inflammation.

Question 31

Approaches to modulating IL-1 activity

Answer 31

* Anti-IL-1 antibodies * Soluble IL-1 receptor * The native IL-1 receptor antagonist (IL-1Ra)

Question 32

IL-1 mediated condition

Answer 32

**Rheumatoid arthritis** characterised by the presence of high levels of IL-1 in the synovial fluid of affected joints

Question 33

Additional negative influences of IL-1

Answer 33

Cartilage degradation and bone resorption

Question 34

Recombinant form of IL-1Ra for treating rheumatoid arthritis

Answer 34

Kineret

Question 35

Kineret

Answer 35

approved product for treating rheumatoid arthritis based on IFN-1Ra

Question 36

How does kineret differ from native form

Answer 36

* Non-glycosolated * Contains an additional N terminal methionine residue

Question 37

Additional approach to IL-1 down regulation

Answer 37

inhibiting the proteolytic enzymes that realease the active interleukin fromits native inactive precursor

Question 38

Example of additional approach to IL-1 down regulation

Answer 38

IL-1b converting enzyme (ICE) which releases active IL-1b from its precursor

Question 39

What produces Interleukin 11 (IL-11)

Answer 39

IL-1 activated bone marrow stromal cells (connective tissue cells) and fibroblasts (stroma synthesising cells)

Question 40

Function of IL-11

Answer 40

Haematopietic growth factor Stimulates: * growth/differentiation of bone marrow cells * Thrombopoiesis

Question 41

What is Neumega?

Answer 41

* Tradename of an IL-11-based product that has been approved for the prevention of thrombocytopenia. * It works by stimulating platelet production and can partially offset the damage caused by chemotherapy.