Vaccines

Question 1

4 features of ideal vaccines

Answer 1

1. Induce immunity in most individuals
2. Give long-lived immunity
3. Not be toxic or induce illness
4. Shouldn’t require boosters

Question 2

Vaccination definition

Answer 2

Deliberately giving an antigen so as to elicit an immune response

Question 3

Immunization definition

Answer 3

Providing the body with specific defenses against an antigen

Question 4

Passive immunization features

Answer 4

Transferring antibodies from one individual to another for protection
Immediate and doesn’t elicit memory response

Question 5

Active immunization features

Answer 5

Vaccination: administer antigen to elicit an adaptive immune response
Formation of memory cells: prolonged protection

Question 6

Live vaccines

Answer 6

Contain attenuated organism (limited virulence)
Cause infection, but not disease
Induces TH1 and TH2 responses

Question 7

How attenuation is achieved

Answer 7

Growing organism in vitro until it loses virulence
Mutate virulence gene
Delete virulence gene

Question 8

Disadvantages to live vaccines

Answer 8

Cannot be used with immunocompromised individuals
Not very stable
Can revert to virulence

Question 9

Killed/inactivated vaccines

Answer 9

Killing virus/bacteria, but preserving antigenic integrity

Question 10

Disadvantages to killed/inactivated vaccines

Answer 10

Mostly induce antibodies only
Require large amounts of antigen (organism doesn’t multiply)
Protection is shorter term- boosters are needed

Question 11

Advantages of killed/inactivated vaccines

Answer 11

More stable storage

Unlikely to cause disease in immunosuppressed individuals

Question 12

Subunit vaccines

Answer 12

Contain defined proteins from an infectious agent rather than the whole organism

Question 13

Disadvantage of subunit vaccines

Answer 13

Only stimulates immunity against a single protein- may not impart full protection
Must choose carefully which antigen to target

Question 14

Toxoid vaccines

Answer 14

Type of subunit vaccine
Used with pathogens in which a secreted toxin is the cause of disease (ex- tetanus)
Toxin is inactivated

Question 15

Recombinant vector vaccine

Answer 15

Type of subunit vaccine
Inserting gene for pathogenic antigen into harmless vector (live organism that doesn’t cause disease)
Vector produces protein

Question 16

Conjugate vaccine

Answer 16

Type of subunit vaccine

Covalently linking “poor” antigen to carrier that is immunogenic

Question 17

DNA vaccine

Answer 17

Type of subunit vaccine
Plasmid carries genetic information of antigen
Injection into muscle cells results in temporary production of encoded protein

Question 18

Disadvantage of DNA vaccine

Answer 18

Potential for DNA incorporation into cellular genome

Question 19

Are DNA and recombinant vector vaccines currently in use?

Answer 19

No- still in clinical testing stage

Question 20

Relationship between vaccine safety and efficacy

Answer 20

Safety is inversely proportional to efficacy
Subunit vaccines are more effective than live-attenuated vaccines, but live-attenuated vaccines are safer than subunit vaccines

Question 21

Adjuvants

Answer 21

Substances that enhance immunogenicity of antigen

Question 22

3 ways in which adjuvants work

Answer 22

Convert soluble proteins into particulate material
Stimulate cytokine production by APCs
Slowly release antigen to maintain antigen half life

Question 23

Benefits of adjuvants

Answer 23

Improved immediate responses to antigen
Fewer boosters needed
Overcome immunosuppression
Target antigens to APCs
Activate APCs
Improved response to targets with low antigenicity

Question 24

ISCOM vaccines

Answer 24

Type of adjuvant

Immunostimulating complex: delivers antigen to cytoplasm by forming micelle that fuses with cell

Question 25

Reasons why vaccines can fail

Answer 25

Interference with maternal antibodies
Senescence
Improper application of vaccine
Physiologic state of recipient
Host genetics
Antigenic variation in pathogen strain
Extremely virulent pathogen strain encountered
Insufficient time to mount immune response
Poor technique

Question 26

Advantage of injection

Answer 26

Ease of anatomic site access

Question 27

Disadvantages of injection

Answer 27

Cost of needles
Capture of animal
Artificial route of entry for most pathogens
Primarily induce IgG responses

Question 28

2 ways that allergy shots work

Answer 28

1. Exposes allergen to immune system in a way that favors IgG production over IgE
2. Inducing T regulatory cells that inhibit allergen-specific B and T cells