Immunomodulation Flashcards
What is the definition of immunomodulation?
The act of manipulating the immune system using immunomodulatory drugs to achieve a desired immune response
What may the therapeutic effects of immunomodulation lead to?
Immunopotentiation, immunosuppression or induction of immunological tolerance
it is used to turn down a part of the immune system that is causing harm, or to potentiate part of the immune system
What is the definition of biologic immunomodulators?
Medicinal products produced using molecular biology techniques including recombinant DNA technology
these complex molecules are similar/the same as proteins in the body
What are the main classes of biologic immunomodulators?
- Substances that are (nearly) identical to the body’s own key signalling proteins
- monoclonal antibodies
- fusion proteins
What are the differences in these anti-TNF drugs?
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The immune system is more likely to react if there is a foreign murine component to the molecule
Adalimumab is a fully human monoclonal antibody so is less likely to cause an immune response
Etanercept is a fusion protein
What is meant by a “chimeric molecule”?
A chimeric molecule has a component that is from an animal origin
What are the 3 methods of immunopotentiation?
- Immunisation (active or passive)
- Replacement therapies
- Immune stimulants
What is the definition of passive immunisation?
The transfer of specific, high-titre antibody from a donor to a recipient
this provides immediate but transient protection
What are the types of passive immunisation?
What are the problems associated with this mechanism?
Types:
- pooled specific human immunoglobulin
- animal sera (containing antitoxins and antivenins)
Problems:
- risk of virus transmission
- serum sickness - type III hypersensitivity reaction
What are the uses of passive immunisation?
- Hepatitis B prophylaxis and treatment
- Botulism
- VZV in pregnancy
- Diptheria
- Snake bites
What is the definition of an active immunisation?
To stimulate the development of a protective immune response and immunological memory
this generates long lasting immune responses that provide long term protection
What immunological material can be used in an active immunisation?
- Weakened forms of pathogens
- killed inactivated pathogens
- purified materials (proteins, DNA)
- adjuvants
adjuvants are added to direct immune responses in certain directions
What are the problems associated with active immunisation?
- Allergy to any vaccine component
- Limited usefulness in immunocompromised patients
- There is a delay in achieving protection
What 4 methods are used in replacement therapies/immune stimulation?
- Pooled human immunoglobulin (IV or SC)
- G-CSF / GM-CSF
- Alpha-interferon
- Y-interferon
When is pooled human immunoglobulin used as a replacement therapy?
In patients with a diagnosis of antibody deficiency states
immunoglobulins are taken out of the serum of the donor
When is G-CSF / GM-CSF used?
Neutropenia
it acts on the bone marrow to increase the production of mature neutrophils
When are a-interferon and y-interferon used?
Alpha interferon:
- used in treatment of Hep C
y-interferon:
- used in treatment of intracellular infections (atypical mycobacteria)
- used in chronic granulomatous disease
- used in IL-12 deficiency
What are the 5 types of immunosuppressants?
- Corticosteroids
- Cytotoxic agents
- Anti-proliferative/activation agents
- DMARDs
- Biological DMARDs
When to corticosteroids tend to be used in treatment?
They are used to reduce the inflammatory response quickly
they affect all functions of the immune system so it is hard to target the use of steroids
they limit unintended damage during acute infection
What are the 6 actions of corticosteroids?
- Decreased neutrophil margination
- reduced production of inflammatory cytokines
- inhibition of phospholipase A2 - reduced arachidonic acid metabolites production
- lymphopenia
- decreased T cell proliferation
- reduced immunoglobulin production
What are the 5 main side effects of corticosteroids?
- Carbohydrate and lipid metabolism problems leading to diabetes and hyperlipidaemia
- reduced protein synthesis leading to poor wound healing
- osteoporosis
- glaucoma and cataracts
- psychiatric complications
In which conditions do corticosteroids tend to be used?
Autoimmune diseases:
- CTD
- vasculitis
- rheumatoid arthritis
inflammatory diseases:
- Crohn’s disease
- sarcoid
- GCA/polymyalgia rheumatica
malignancies:
- lymphoma
allograft rejection
Why are corticosteroids not used for long term therapy?
They are used to achieve a quick and profound immune response
other agents are used to maintain the immunosuppression after the corticosteroids have been administered
this is due to the side effects
Why are costimulatory molecules important in the immune response?
Which cytokine is secreted by T cells allowing for more activation?
Costimulatory molecules allow T cells to be fully stimulated
IL12 is secreted by T cells, which allows T cells to continue with the program of activation