Immunisation

Question 1

What are the two types of immunisation?

Answer 1

Active and passive

Question 2

What does immunisation involve?

Answer 2

using vaccines or antibody-containing preparations to provide immune
protection to provide immune protection against specific diseases

Question 3

Describe passive immunisation

Answer 3

immediately active, effective for post-exposure prophylaxis, no memory, no need for
fully-functional immune system (eg. use in immunocompromised hosts, young, elderly)

Question 4

Describe active immunisation

Answer 4

Vaccines - long-duration, lag before it is active, usually requires multiple immunisations

Question 5

Describe passive immunisation

Answer 5

Passive immunisation is via immunoglobulins – provides immediate protection
 Standard immunoglobulins (human, animals) – non-specific, pooled plasma from donors,
immunoglobulins vs. many common infections
 Human hyperimmune serum (high titre) – specific, from donor with high titres of antibodies to a
specific virus, against specific (single) pathogen or antigen

Question 6

Examples of when passive immunisation is used

Answer 6

rabies

hep b

Question 7

What are the types of active vaccination?

Answer 7

Live attenuated vaccines
Killed and subunit vaccines
Vectored vaccines
Adjuvants

Question 8

Goal of active vaccination

Answer 8

stimulating the
vaccinee’s immune system, to mount an adaptive
immune response to a specific pathogen

Question 9

Describe live attenuated vaccines

Answer 9

May be attenuated form of virulent organism (eg. Measles, Sabin polio vaccine) or an
immunologically-related organism (eg. vacccinia)

Question 10

Good things about live attenuated

Answer 10

Can still replicate - can spread to vaccines family

Question 11

Bad things about live attenuated

Answer 11

Reversion to full virulence

Question 12

Describe killed or ‘inactivated’ vaccines

Answer 12

May be whole organism, subunit, isolated toxins – antigen preparation chemically treated to
inactivate infectivity and toxicity

Question 13

Describe whole organisms killed vaccines

Examples of whole organism killed vaccines

Answer 13

Heat or formaldehyde inactivated
shorter term immunity than attenuated vaccines (need boosters)
e.g. Cholera , Perussis

Question 14

Describe subunit vaccines

Examples of subunit vaccines

Answer 14

• antigenic viral surface components are isolated
• these elicit a neutralising antibody response

Examples:
Influenza
Genetically engineered protein subunit from HBV
HPV

Question 15

Example of inactivated exotoxin

Answer 15

Tetanus toxoid - need boost every 10 years

Question 16

Describe conjugate vaccines

Answer 16

Antigenic polysaccharide from bacterial cell wall covalently-coupled (conjugated) to protein carrier
(eg. tetanus toxin); gives higher antibody titres than unconjugated polysaccharide vaccine
- Upon vaccination, the protein carrier provides peptides for MHC presentation, thus providing T cell
help for polysaccharide-specific B cells to make antibodies

Question 17

Describe toxoid vaccines

Answer 17

Inactivated derivatives of bacterial endotoxins (eg. diphtheria toxin, tetanus toxin – Clostridium
tetani)
- Rendered non-toxic by chemical (formalin) treatment or genetic engineering, but remain immunogenic

Question 18

Describe recombinant vaccines

Answer 18

Created via genetic engineering; the gene encoding a viral protein is inserted into a different, non-
pathogenic virus
- When the carrier virus replicates, the vaccine protein is produced, eliciting an immune response
- Examples are the hepatitis B vaccine, and human papillomavirus vaccine (HPV: a recombinant virus-
like particle is created in yeast, expressing single proteins of four different HPV strains, thus inducing
immunity to all four strains at once)

Question 19

MMR vaccine issues

Answer 19

 Adverse reactions, rarely serious – 10% of children develop fever, malaise, and a rash 5-21 days
after the first vaccination
 3% develop joint pain lasting on average 18 days
 Anaphylaxis is a rare but serious side effect
 Controversy: Andrew Wakefield, 1998 – MMR vaccine linked to autism and enterocolitis;
discredited, but led to decline in vaccination rates and increase in disease rates

Question 20

What are adjuvants?

Answer 20

Addition of substances that create a state of inflammation, helps stimulate effective immune
response