Vaccinations Flashcards
Recall the immune response to vaccines
- antigen introduced –> taken by antigen presenting cell
- presents to naive T-helper cell
- presents to Naive B-cell –> plasma cells production and antibody production
+ T- cells might enable and kill infectted cells
What are the criteria that would make an ideal vaccine?
- Generates immunological memory
- Practical - single injection, easy storage, inexpensive
- No adverse effects
What are passive vaccinations? How long does the protection usually last for?
Passive = direct administration of antibodies, not introducing parts that trigger immune reponse
Immunity last for about 3 weeks
Name examples of passive vaccinations that can be gien
- HNIG (Human Normal Ig) – Hep A and Measles
- HBIG (Hep B Immunoglobulin) – Hep B
- HRIG (Human Rabies Immunoglobulin) – Rabies
- VZIG (Varicella Zoster Immunoglobulin) – Varicella
- Paviluzimab – monoclonal antibody for RSV (Respiratory Syncytial Virus)
What is immune senescence?
What are the drivers of it?
= Natural deteriation of immune system by ageing
- Increased frequency of terminally differentiated effector memory T cells
- Increased expression of senescence markers
- Much reduced production of recent thymic emigrants which drive the naïve T-cell repertoire
What is the principle behind a live attenuated vaccine?
Use live pathogen but modified (attenuated) to vaccinate and trigger immune response
What are examples of life atenuated avaccines?
MMR
BCG
Yellow fever
Zostavax
Typhoid (oral)
Polio (oral)
Influenza (nasal spary for children 2-17)
Shat are the advantage and disadvantages of life attenuated vaccines
Advantages
- Genreally very good immune response
- against multiple antigens (different strains)
- all phases of immune system
–> may give life-long prottection
Disadvantages
- possible virulence
- potential spread to immunosuppressed contacts
What is the rationale behhind inactivated /component vaccines?
Administration of inactivated shell or fragments of membranes that antibodies can be formed towards
Name examples of inactivated vaccines
- Influenza (inactivated)
- cholera
- polio (salk)
- hep A
- pertussis
- rabies
Name examples of component/ subunit vaccinations
Hep B [HbS antigen],
HPV [Capsid],
Influenza recombinant (less commonly used - inactivated more commonly in adults, life attenuated more commonly in children)
What are toxoid vaccines?
Name 2 examples
Diseases where the toxoid are causing disease –> vaccination against effect
Examples
Diphteria and Tetanus
What are the advantages and disadvanatages of inactivated or compoundvaccines?
Advantage
- no risk of reversion to virulent form –> immunodeficiency
- easier storge
- lower cost
Disadvantage
* generally poorer immune response –> may need multiple injections or modification to enhance immunogenity
What are conjugate vaccines?
Name 2 examples
Sub-type of inactivated vaccines
Something added to enhance T-cell immunity –> better long term protection
Examples of conjugates:
Polysaccarite + proteins e.g.
Haemophilus Influenzae B
Meningococcus
Pneumococcus (Prevenar)
What is an adjuvant added to a vaccine?
How do they usually work?
Adjuvant = something that increases the immune response without altering its specificity
MOA - many different MOA, but often mimic action of
1. PAMPs on TLR and other PRR
Prolongs antigen exposure: Alumnninim salts that are only slowly absorbed
Explain how mRNA vaccines work
RNA fragment in lipid shells are injected into human
–> RNA integrated and translated to express spike protein on cells
–> stimmulated immune response in T and B cells against expressed protein on cells
What are viral vector vaccines? Can you name some examples?
Similar principle to mRNA vaccine, but mode of delivery is viral vector
DNA of relevant protein (Covid spike protein)
inserted to viral vector
to produce vaccine
What is the difference between monovalent and multivalent vaccines?
Monovalent = protects against one strain
Multivarlent : protects against several different strains of the pathogen
What characteristics should be present in order to make disease eradication possible?
- No reservoir: animal, latent reservoir in humands
- onely one or small number of strain
- vaccine must cause long-lasting immune response
What are dendritic cells vaccines?
How are they manufactured?
What is their clinical significance?
Personalised vaccines against certain malignancies –> Dendritic cells are altered to present malignant proteins to trigger immune response against cancer
- extract dendritic (Antigen-presenting cell, APC) + part of tumour
- Culture them
- implant APC back into patient and thy will present t-cells to boost immune response
What is the routine UK vaccination scedule for adults?
- 50yrs onwards: flu annually
- 65 yrs: Pneumococcal (PPV)
- 70 yrs: Shingles
- Pregnancy (any age): Flu during appropriate season, DTaP/IPV from 16/40
gestation
+ COVID
