Chapter 18: Applications of Immune Responses

Question 1

What are vaccines?

Answer 1

• a suspension of organisms or portions of organisms (antigens) that can stimulate an immune response without causing disease

Question 2

What do vaccines cause?

Answer 2

• immune system produces memory cells to the specific antigen

Question 3

Why are vaccines needed?

Answer 3

• many communicable diseases can be controlled by behavioural or environmental methods
  ex. STI’s can be controlled by condoms
  ex. Cholera can be controlled by proper sanitation

Question 4

What happens when behavioural or environmental methods fail? (2)

Answer 4

• bacterial diseases can be treated with antibiotics
• viral diseases generally cannot be cured`

Question 5

What would be the best method to control diseases that cannot be cured?

Answer 5

VACCINES

Question 6

What are the 5 types of vaccines?

Answer 6

1. Attenuated whole agent vaccines
2. Inactive whole agent vaccines
3. Toxoids
4. Subunit vaccines
5. Conjugated Vaccines

Question 7

What are attenuated whole agent vaccines?

Answer 7

• use weakened (living) microbes
• minor mutations so that it does not cause disease
  ex. a virus that can adsorb, penetrate, uncoat, but cannot reproduce

Question 8

How do attenuated vaccines work?

Answer 8

• closely mimics an actual infection
• stimulates both antibody mediated (B-cell) immune response and cell mediated (T-cell) immune response

Question 9

How long do attenuated vaccines last?

Answer 9

• often confers life-long immunity
  ex. MMRV (measles, mumps, rubella, Varicella)

Question 10

What are the risks of attenuated vaccines? (2)

Answer 10

• may still be able to cause disease in immunocompromised patients
• living micro me revert back to its pathogenic form (ie. through a second mutation!!)

Question 11

What are Inactive whole agent vaccines?

Answer 11

• Use whole microbes that have been killed

Question 12

What are examples of VIRUSES that use inactive vaccines?

Answer 12

rabies, influenza, Polio (Salk vaccine)

Question 13

What are examples of bacteria that use inactive vaccines?

Answer 13

• Vibrio cholera

Question 14

What are toxoids?

Answer 14

• inactivated toxins from purified proteins

Question 15

What occurs in toxoid vaccination? (2)

Answer 15

• immune response acts against toxoid
• stimulates only the Ab mediated response (B cells)

Question 16

how many vaccines do you need for toxoid vaccination? (3)

Answer 16

• usually requires a series of injections for full immunity
• may require booster shots
  ex. It’s recommended to get the DTaP vaccine (diphtheria, tetanus, pertussis) every 10 years

Question 17

How long does immunity last for toxoids?

Answer 17

not very long

Question 18

What are subunit vaccines?

Answer 18

• contain only purified components from viruses or bacteria

Question 19

What is most likely to induce an immune response in subunit vaccines? (2)

Answer 19

• antigens most likely to induce immune response
• stimulates only the Ab mediated response

Question 20

How is S. pneumoniae vaccine a subunit vaccine?

Answer 20

• Pneumoshot contains purified capsule polysaccharides

Question 21

How is the Hep B vaccine a subunit vaccine?

Answer 21

• viral coat proteins produced in genetically modified yeast

Question 22

Are subunit vaccines even safe?

Answer 22

• extremely safe because disease causing agent is not present

Question 23

What are conjugated vaccines? (2)

Answer 23

A polysaccharide antigen is combined with a protein antigen
- results in a stronger immune response

Question 24

When are conjugated vaccines used?

Answer 24

• children’s immune systems do not respong well to capsule polysaccharides (in subunit vaccines)

Question 25

How is the Haemophilus influenzae vaccine a conjugated vaccine? (2)

Answer 25

• capsule combine w diphtheria toxoid
• can induce response in children as young as 2 months