principles of immunisation Flashcards
what are antigens?
parts of bacteria and viruses, which are recognised by the immune system
Antigens are usually proteins or polysaccharides (sugars)
The immune system generates a response to antigens – often by the production of antibodies
what are antibodies?
: proteins which bind to antigens
Antibodies are very specific to individual antigens
When an antibody-antigen complex is formed, this alerts other immune cells (lymphocytes: B-cells and T-cells)
what are B cells?
Humoral immune system
mature in the bone marrow
triggered to produce antibody when encounter foreign antigen
what are T cells?
Cell-mediated immune system
mature in the thymus
CD4+ cells CD8+ cells
orchestrate response of immune system by binding to other cells and sending out signals
what are some advantages of passive immunity?
rapid action
post exposure
can attenuate illness
outbreak control
can be used if contraindication to active vaccination
what are some disadvantages to passive immunity?
short term production
short term window
blood derived
hypersensitivity reaction
expensive
what are whole pathogen vaccines?
Live attenuated vaccines
-Rotavirus, nasal flu, MMR, shingles, BCG, oral
polio
Inactivated whole organisms
-Inactivated polio vaccine (IPV), some flu
vaccines (‘split virion’), rabies
what are subunit vaccines?
Recombinant protein vaccines
-Hep B, HPV, MenB
Toxoid (inactivated toxin) vaccines
-Diphtheria, tetanus, acellular pertussis
Conjugate vaccines - polysaccharide +
immunogenic protein
-Hib, MenC, MenACWY, PCV13
what are virus like particles vaccines?
Naturally occurring or manufactured protein structures
Can act as antigen, or present other antigens; also act as adjuvant
what are outer membrane vesicles?
‘Bubble’ of bacterial cell membrane carrying antigens, and acts as adjuvant
what are nucleic acid vaccines?
Provide genetic instructions of antigen for body cells to produce
-mRNA vaccines – Pfizer/BioNTech and
Moderna SARS-CoV-2 vaccines
-DNA vaccines – given with electroporation to
enable cells to take up
what are viral vectored vaccines?
Use naturally harmless or attenuated virus to deliver genes for target antigen into body cells
-Replicating e.g. Ervebo (rVSV-ZEBOV) vs.
Ebola
-Non-replicating e.g. Oxford-AstraZeneca
SARS-CoV-2 vaccine
what are some contraindications to vaccines?
Confirmed anaphylaxis reaction to previous dose of same antigen or vaccine component
Live vaccines:
-Immunosuppression (primary, radiotx, high-
dose steroids/other drugs, HIV)
-Pregnancy
Egg allergy (yellow fever, flu)
Severe latex allergy
Acute or evolving illness – defer till resolved/ stabilised
what is diptheria?
URTI characterized by sore throat, low grade fever
what causes diptheria?
Caused by aerobic gram-positive bacterium Corynebacterium diphtheriae
