Immunology 7 - Immune-modulating therapies 1 & 2 Flashcards
What mediates immunological memory?
WHat are the characteirstics of memory T cells and memory B cells?
T and B cells
T cells
- different expression of cell surface markers - allows migration to non-lymphoid tissue where microbes may enter
- longevity
- rapid, robust response to subsequent antigen exposure
B cells
- lonevity
- pre-formed antibody - IgG, high affinity
- rapid, robust response to subsequent antigen exposure
By what mechanism can B cells provide immunological memory?
High affinity IgG remains circulating in blood
What antibody is used in influenza vaccine?
WHen does the vaccine start to work and how long is it effective for?
Antibody against haemagluttinin - this is the protein used by influenza to enter the cell
Starts working after 7 days; provides protection for up to 6 months
What is the best predictor of immunity to influenza following a vaccine?
IgG against haemaglutinnin (moreso than CD8 T cells)
Why is adjuvant used in some vaccines?
It stimulates an innate immune response
What are the indications for antibody replacement in a patient (general antibody replacement) and what is the process?
- Prepare from a pool of donors
- Infusion will contain IgG to a wide range of unspecified organisms
- Administer either IV or subcutaneously
Indications:
- Primary antibody deficiency (3):
- X-linked agammaglobulinaemia
- X-linked hyper IgM syndrome
- Common variable immune deficiency
- Secondary antibody deficiency (3):Haematological malignancies:
- CLL
- Multiple myeloma
- After bone marrow transplantation
- Ohers
- ITP
- kawasaki’s disease
- guillan barre syndrome
- measles
Give examples of specific immunoglobulins that can be given to patients
Hep B
tetanus
rabies
VZV
HIV - post exposure prophylaxis contains HIV immunoglobulin
explain the 4 main ways of adoptive cell transfer
- virus specific T cell expansion
- used to prevent EBV associated post transplant lymphoproliferative disease
- you take out T cells from Patient/another donor and inject virus (EBV) so the T cells are now able to mount an immune response against EBV
- the active T cells can then be transferred back to the patient so after the transplant they can mount a response against EBV - Tumour infiltrating lymphocyte (TIL) T cell therapy
- take tumour out and culture with IL2
- this stimulates T cell expansion within population
- isolate the T cells and inject them back into the patient - T cell receptor T cell therapy
- take out T cells from patient with malignancy
- insert gene that codes for specific TCR - targeting tumour surface antigen
eg CD19 to target ALL
- Chimeric antigen receptor T cell therapy
- like T cell receptor T cell therapy but with chimeric antigen receptor (made of an antibody and TCR)
What monoclonal antibody can be used in melanoma treatment?
Ipilimumab (anti-CTLA4) or Nivolumab, an antibody specific for PD-1
These are immune checkpoint inhibitors - enhance the T cell response
In what disease can IFN gamma be given therapeutically?
Chronic granulomatous disease
In what disease can IL2 be given therapeutically?
Renal cell carcinoma
IL-2 expands NK and T cell responses via the IL-2 surface receptor
**think you have 2 kidneys; IL2**
In what diseases can INF alpha be given therapeutically?
what about interferon beta?
- Interferon alpha
ABC
Alpha for hepB
CML
+ multiple myeloma
+ hairy cell leukamiea
- interferon beta
- relapsing MS (past) - bechet’s (B FOR BECEHETS)
How do steroids inhibit the immune response?
Side effects of corticosteroids
Inhibit phospholipase A2 which is a key enzyme in prostaglandin formation
Also decrease phagocyte trafficking (hence there is a transient increase in neutrophil count)
Also cause lymphopenia - as lymphocytes get sequestered in lymphoid tissue
Side effects
Metabolic effects:
- Cushingoid Sx
- Diabetes
- central obesity
- moon face
- lipid abnormalities
- osteoporosis
- hirsutism
- adrenal suppression
- Other effects:
- Cataracts
- glaucoma
- peptic ulceration
- pancreatitis
- avascular necrosis of hip and knee
- Immunosuppression
Can use the mnemonic BECLOMETHASONE
Buffalo hump
Easy bruising
Cataracts
Larger appetite
Obesity
Moonface
Euphoria
Thin arms & legs
Hypertension/ Hyperglycaemia
Avascular necrosis of femoral head
Skin thinning
Osteoporosis
Negative nitrogen balance
Emotional lability
*causes transient leukocytosis and neutrophilia
Recall 4 examples of anti-proliferative agents
Cyclophosphamide
Azothioprine
Mycophenalate
METHOTREXATE
CAMM
**not calcineurin inhibitors
What is the mechanism of action of cyclophosphamide?
Alkylating agent.
Alkylation of guanine –> inhibition of DNA synthesis (damages DNA)
*can’t use for too long due to toxicity
B cells > T cells
Side effects of cyclophosphamide
- Toxic to proliferating cells:
- Bone marrow suppression
- Hair loss
- Sterility (male >> female)
- Haemorrhagic cystitis
- Malignancy:
- Bladder cancer
- Haematological malignancies
- Non-melanoma skin cancer
- Infection:
- Pneumocystis jirovei
MAIN ONES TO. BE AWARE OF: HAEMORRHAGIC CYSTITIS
(C AND C)
as it is excreted by the kidneys
What is the mechanism of action of azothioprine?
6-mercaptupurine : it’s a purine analogue
That interferes with normal purine synthesis
Affects T cells > B cells
What must always be checked before prescribing azothioprine?
TPMT activity
polymorphism means that they cannot metabolise azathioprine which leads to excess bone marrow toxicity
Explain how methotrexate works, main side effects to be aware of
How can plasma exchange be used to treat autoimmune diseases?
Removes problematic antibody (in exchange - you exchange it for albumin)
Need to give alongside an antiproliferative agent as it can cause a rebound increase in antibody production…
Only for severe disease
Indications: type II hypersensitivity reactions eg goodpasture’s, myasthenia gravis, vascular rejection, antibody mediated rejection
How do calcineurin inhibitors work?
Calcineurin causes an upregulation of IL2 - inhibition of this allows cell proliferation
**rmb il2 is a key cytokine that drives T cell proliferation**
Examples of inhibitors of cell signalling
- calcineurin inhibitors
- JAK inhibitors
- PDE4 inhibitors
(also mTor inhibitor - sirolimus- inhibits IL2 pathway)
Give examples of a calcineurin inhibitor?
Mechanism?
Tacrolimus vs ciclosporin
Ciclosporin and tacrolimus
*inhibit calcineurin production which inhibits IL2 production (T cell activation and proliferation is blocked)
Indications: rejection prophylaxis in transplantation
Side effects: Nephrotoxic, hypertension, neurotoxic (+ dysmorphic features + gingival hyperrophy with ciclosporin)
CICLOSPORIN HAS MORE SIDE EFFECTS THAN TACROLIMUS
**cycling is dangerous** **taxi is safe**
Give 2 diseases in which JAK2 inhibitors can be useful?
Example
Rheumatoid and psoriatic arthritis
Tofacitinib- Jak1/3 inhibitor
**none of the haematological malignancies!!
rmb PCV is treated with venesection
By what mechanism do PDE4 inhibitors work, and in what disease are they useful?
Inhibition of PDE4 –> inceased cAMP
cAMP modulates cytokine production
–> fewer cytokines
Useful in psoriasis and psoriatic arthritis
Example: Apremilast
Recall 2 immune-modulating therapies that are useful in the prophylaxis of allograft rejection
Anti-thymocyte globulin - blocks T cell proliferation
Anti-CD25- daclizumab
Wha type of antibody is rituximab?
Anti-CD20
attacks mature B cells, but leaves plasma cells intact, so antibody production is not affected much
Uses:
- lymphoma
- rheumatoid arthritis
- SLE
- vasculitis
What monoclonal antibody can be used in IBD treatment?
Vedolizumab
Anti - alpha4beta7 integrin
What is infliximab?
Indications
Anti-TNF alpha
Indications: \
Rheumatoid arthritis
Ankylosing spondylitis
IBD
Psoriasis and psoriatic arthritis
Familial Mediterranean feve
What monoclonal therapy can be used in osteoporosis?
anti-RANK/RANK-ligand
Denosumab
What is the mechanism of action of tofacitinib
JAK inhibition (jak 1 or jak 3)
What is the mechanism of action of apremilast?
Anti-PDE4
What is the mechanism of action of basilixumab?
Anti-CD25 (alpha chain of interleukin 2 receptor)
What is the mechanism of action of Abatacept?
when is it used?
CTLA4 infused immuonglobulin
it enhances the activity of CTLA4 (opposite of imilimumab)
used in rhuemtaoid arthritis
What is the mechanism of action of rituximab?
Anti-CD20
What is the mechanism of action of natalizumab?
Anti-alpha4 integrin
What is the mechanism of action of tocilizumab?
Anti-IL6-R
What is the mechanism of action of muromonab
Mouse monoclonal against CD3
3 vowels in this
What is the mechanism of action of dacilizumab?
Anti-CD25 (alpha chain of interleukin 2)