Vaccination and immune therapies Flashcards
1
Q
natural passive immunity
A
colostrum
2
Q
artificial passive immunity
A
transfer of antibodies from other humans, horses, sheep or rabbits
3
Q
How is therapeutic anti-sera produced ?
A
- Produced by a donor animal
- Donor animal is immunized with non-lethal doses of antigen and the induced response produces neutralizing antibodies
- At certain intervals, the blood from the donor animal is collected and antibodies are purified
4
Q
Applications of anti-sera
A
- Rapid treatment of acute illness such as Ebola, RSV, measles, tetanus, hepatitis A and B, rabies
- Snake venom or toxins
- Preventative measure – cytomegalovirus after transplantation, yellow fever
5
Q
Advantages of anti-sera
A
- Transfer of antibodies is quick acting, passive immunity can support deficient immune systems
6
Q
Disadvantages of anti-sera
A
Antibody levels fall and protection fades within months, antibody treatments must be given via intravenous injection, ‘serum sickness’, antisera is expensive and complication to manufacture and store
7
Q
monoclonal antibody production
A
- Mouse injected with the antigen
- Spleen cells combined (fusion) with myeloma cells
- Hybridomas are cultured
- Antibodies are harvested
8
Q
Advantages of monoclonal antibodies
A
- Single specificity, near unlimited supply, rare specificities can be isolated, antibodies can be manipulated
9
Q
How to humanise a mouse monoclonal antibody
A
- Isolate the CDR (complementarity determining region) and replace the CDR of a human antibody with the murine (Mouse) monoclonal antibody
10
Q
modern monoclonal antibodies
A
- Directly from human B cells, phage display, EBV transformation, in vitro expansion and selection
- Could be used to select for novel pandemics like Ebola
11
Q
ideal vaccines are …
A
- Long lasting, safe, stable in field conditions, easy to store and administer, single dose, affordable and accessible to all, pathogen evolution-proof
12
Q
Live attenuated vaccines are more or less effective than killed or sub-unit ?
A
more
13
Q
Traditional vaccines and their limitations
A
- Inoculation of many different attenuated live vaccines to eggs of a chicken
Limitations:
- Not all organisms grow in culture
- Live pathogens – safety to lab personnel
- Expense
- Insufficient attenuation
- Reversion to infectious state
- May need specialist storage (refrigeration)
- Not applicable for all infectious agents
14
Q
What might a sub-unit vaccine contain …
A
A PAMP like polysaccharide cell walls
15
Q
Advantages to sub-unit vaccines ?
A
o No extraneous pathogenic particles like DNA
16
Q
Disadvantages to sub-unit vaccines ?
A
o Protein may differ when not in situ
o Production can be expensive
17
Q
Vector vaccines
A
antigen gene inserted into the vaccinia virus genome (with all virulent factors removed) e.g., Rabies virus G protein, Hepatitis B surface antigen, influenza virus NP and HA proteins
18
Q
VLP
A
Virus-like particles (VLP):
- Non-enveloped VLPs – protein only, single layer, self-assembled, homogeneous nanoparticles derived from the coat proteins of viral capsids
- Enveloped VLPs – contains lipid layer.
19
Q
What is a protein-polysaccharide conjugate ?
A
contains a polysaccharide tail and carrier protein, binds to the B cells with T cell help
20
Q
What does viral vector vaccine contain and trigger ?
A
Viral vectored – use of a virus to exchange and vector another pathogens genome
- Avoid pre-existing immunity to the vector by using a chimpanzee adenovirus
- Spike protein encoding DNA.
- Triggers type I interferon and proinflammatory cytokines.
21
Q
vaccine delivery routes
A
- Intranasal
- Oral
- Aerosolized
- Intradermal
- Intravenous
- Intramuscular
- Intraperitoneal
- In ovo
22
Q
Vaccine adjuvants
A
– essential for enhancing and directing the adaptive immune response to vaccine antigens otherwise might lead to tolerance
23
Q
examples of new adjuvants
A
dose sparing (less antigens), rapid response to pathogens, vaccine response broadening, vaccines for elderly, therapeutic vaccines, new T cell vaccines, reduced number of immunisation
24
Q
What adjuvants would activate DC
A
most PAMPs: Cell walls, microbe-like DNA, viral RNA, flagellin protein
25
What is the best way of using DC in vaccines
inject intramuscularly
26
criteria for adjuvants
- Extend the presence of antigen (reservoir)
- Locally activate macrophages and lymphocytes
- Support the local production of cytokines
- Activate antigen presenting cells support absorption, migration and present antigen.
27
examples of adjuvants
Alum, MF59, AS04, AS03, AS01, CpG-1018
28
benefits to adjuvants
enhance/ accelerate the immune response, prolong the response, focus the response, diverse the response, increase antibody affinity, improve long term memory, special patient populations, dose sparing.
29
risks of adjuvants
Increase reactogenicity (local, systemic), nonspecific immune activation (immune mediated disease, organ specific, inflammatory disease)
30
polio 2020 vaccine
contained a revertant mutant that actually helped spread the pathogen
31
advantages to live-attenuated vaccines
o Activate all phases of the immune system
o Provide more durable immunity; boosters are required less frequently
o Low cost
o Quick immunity
32
disadvantages to live-attenuated vaccines
o Secondary mutation can cause a reversion to virulence
o Can cause severe complications in immune-compromised patients
o Some can be difficult to transport due to requirement to maintain conditions.
33
OAS
antigenic imprinting
- Original antigenic sin – first exposure shapes immune responses to subsequent infection/vaccination
34
Steps in vaccine development
1) Recognize the disease as a distinct entity
2) Identify etiologic agent
3) Grow agent in laboratory
4) Establish in animal model for disease
5) Identify an immunologic correlate for immunity to the disease – usually serum antibody
6) Inactive or attenuate the agent in the laboratory or choose antigens
7) Prepare candidate vaccine following good manufacturing procedures
8) Evaluate candidate vaccine for ability to protect animals
9) Prepare protocol for human studies
10) Apply for investigational new drug approval
11) Phase 1 – human trials in safety and immunogenicity – dose response (septic shock)
12) Phase 2 – safety and immunogenicity (protection)
13) Phase 3 – efficacy
14) Submit product licensure application
15) Advisory committees review and make recommendations
16) Marketing post-licensure surveillance for safety and effectiveness (Phase 4)
35
radioimmunoassay
- Infected serum sample mixed with radioactive antigen and based on competitive binding we can sense and specify the affinity.
36
ELISA
colour change of substrate-enzyme interaction
37
Immunotherapy for Rheumatoid arthiritis
- TNF-alpha inhibitors, monoclonal antibodies targeting TNF-alpha and cytokine receptors, T cell therapy
- Initiation and progression citrullination of peptides that activates macrophages
38
Immunotherapy for Cancer
- Block: monoclonal antibodies targeting specific cancers
- Deplete: monoclonal antibodies targeting specific proteins
- Block: inhibit checkpoints to activate anti-tumour T-cells
- Enhance: CAR-T cell technology and personalised medicine
39
DMARDs
Disease-modifying antirheumatic drugs
40
Tumour necrosis factor alpha (TNF-alpha)
- A cytokine in systemic inflammation
- Mainly produced by activated macrophages and monocytes, but also by other types such as epithelial cells, astrocytes, adipocytes
- A pyrogen and can induced fever, cell death and inflammation
- Overproduction of TNF-alpha has been implicated in many diseases like arthiritis, inflammatory bowel disease, psoriasis
41
blocking the inflammatory cytokine
- Monoclonal antibodies’ binds to soluble cytokine, neutralizing
- Monoclonal antibody binds to receptor blocking for the cytokine.
42
How does the immune system target cancers ?
1) Cancer cell dies and releases antigen
2) DC uptake antigens
3) APC and T cell communicate at the lymph nodes
4) Trafficking of T cells to the tumor (CTL)
5) Infiltration of T cells into tumours
6) Recognition of cancer cell by T cells
7) Killing of cancer cells
43
HER2
- Epidermal growth factor (EGF)
o Small protein hormone involved in cell proliferation
o Binds to EGFR on cell membrane
o Leads to receptor dimerization and stimulate Ras-MAP kinase
o EGF is a family of proteins
TGF – alpha
AR
EPR
NRG1-4
- HER2 has no ligand: activated when ligand is bound to 1, 3 or 4
- Amplification of HER2 gene leads to increased cell division and growth
- Monoclonal antibodies target HER2 and improve strategies – dual targeting and Ab-drug conjugates
44
Rituximab
- Binds to B cells leads to ADCC and apoptosis
- First Tumour cell-depleting monoclonal antibody ever
45
Tumour antigens
- Neoantigens: mutations in normal human proteins and recognized as ‘foreign’ by the immune system
- Type I MHC will present peptides in the surface
- Recognised as foreign by CD8+ cell (cytotoxic)
- Often CD8+ T cells require further activation to attack tumour cells
46
CAR T cells
chimeric antigen receptor T cell
- CARs lack TCR-alpha and beta-chains: single extracellular domain derived from immunoglobin VH and VL domains
- Intracellular cytoplasmic region also contains co-stimulatory domains that enhance tumour killing activity of T cells
47
why do mRNA vaccines need to be cold-chain stored ?
mRNA degrades easily due to RNases and hydrolysis
48
alum role in vaccine formulation
Enhances the immune response via inflammation
49
A key risk of CAR T cell therapy is:
Cytokine release syndrome (CRS)
50
Checkpoint inhibitors targeting CTLA-4 act primarily on:
Naive T cell activation in lymph nodes
51
Which of the following is most likely to lead to cytokine storm in immunotherapy?
CAR T cell activation
52
History of vaccinations
first scientifically described in 1796 by Dr. Edward Jenner
* tested empirical knowledge: mild cattle disease cowpox
protects against deadly human disease smallpox
* inoculated 8-years-old boy with exudate from cowpox
pustule: full protection against smallpox
53
spleen cells + myeloma cells =
hybridoma
54
what is a toxiod vaccine ?
bacterial toxin that has been chemically/heat treated
can be used for tetanus and diphtheria
55
vaccinia virus vaccinations examples
Rabies, Hepatitis B, influenza
56
outer membrane vesicle vaccines
blebs that are made of gram-negative bacteria contianing LPS, outer membrane proteins and virulence factors
they are meant to mimic bacteria
57
polysaccharide vaccines vs protein-polysaccharide conjugate vaccines
polysaccharide - no production of memory B cells, short-lived antibodies, no affinity maturation
conjugate - affinity maturation, memory B cells, long-lived antibody production, engage T helper cells
58
What does the genes code for inn the viral vectored vaccines ?
spike proteins
59
Which cell takes up the produced antigens from a virally vectored vaccine ?
DC
60
How can a vaccine provide mucosal immunity ?
oral delivery
61
attenuated
edited to not cause the disease but still be a recognisable pathogen
62
adjuvants help which immune system
adaptive
63
Adjuvants can provide .... for immune recognition
PAMPs, like genetic material or cell wall or flagellin
toll like, nod like, rig like
64
What stages do most adjuvants work on ?
antigen uptake and activation of DC, migration
65
live attenuated vaccines can lead to ... mutants that help spread the pathogen
revertant
66
antigenic imprinting
the idea that the first exposure imprints the immune system, so that when you are infected by a different variant your immune system responds based on the first exposure rather than adapting to the new.
immune system uses old B cells on drifting and shifting pathogens like flu and covid
67
4 phases of vaccine development
preclinical
1. human clinical trials
2. expanded clinical trials
3. efficacy and safety of a diverse population
4. post-licensure/surveillance
68
How does a TNF-alpha inhibitor work ?
bind to the cytokine or block the TNF receptors
these could be monoclonal antibodies
69
IL-6 inhibitors
prevents cytokine storms reducing inflammation and CRS
70
CD-80 inhibitors
prevent co-stimualtion of B7 therefore T cells are deactivated
71
rituximab
targets CD20 on b cells, blocking their activation leading to ADCC and apoptosis
72
where are neoantigens presented ?
MHC class 1, recognised by CD8 cells
73
How can a tumour suppress T-cell activation ?
CTLA-4 and PD1
74
How can T-cell suppression from the tumour be prevented ?
use of monoclonal antibodies to target CTLA-4 and PD1
this can be used in combination therapy
75
CARs lack ... but contain ...
TCR alpha and beta chains
intracellular cytoplasmic region that enhances tumour killing activity
