Vaccination (Lec 8)

Question 1

Live-Attenuated Viruses

Answer 1

• weakened forms of viruses that can still replicate in the body but don’t cause disease in healthy individuals
• commonly used in vaccines to trigger a strong and lasting immune response
• Not suitable for immunocompromised patients

Question 2

Live-attenuated viruses: new generation

Answer 2

• virulence gene is isolated from the virus and either mutate it or delete it
• makes it harder for the virus to revert to wildtype infectivity
• makes it safer for immunocompromised patients

Question 3

Killed/Inactivated Virus

Answer 3

• Heat or chemically inactivated virus, cannot replicate in the body
• not as strong of an immune response
• requires multiple doses
• suitable for immunocompromised patients

Question 4

Protein Subunit Vaccines

Answer 4

• uses pieces of the pathogen (often proteins or protein fragments) to stimulate an immune response
• No genetic material, cannot replicate
• not as strong of an immune response
• requires multiple doses
• suitable for immunocompromised patients

Question 5

Conjugate Vaccines

Answer 5

• type of subunit vaccine
• protein attached to a carbohydrate to elicit an immune response
• can use toxoids (inactivated toxin) as protein

Question 6

Conjugate vaccine vs polysaccharide vaccine

Answer 6

Polysaccharide:
- no production of memory B cells
- short lived antibody production
- no affinity maturation
- no immune response in infants <2 years
Conjugate:
- affinity maturation
- induction of memory B cells
- long-lived antibody production
- improved immune response in infants

Question 7

How do conjugate vaccines work?

Answer 7

• B cell binds bacterial polysaccharide component of vaccine conjugate
• conjugate is internalized and degraded
• peptides from the toxoid are presented to the T cell, which activates the B cell
• activated B cell differentiates into a plasma cell producing anti-polysaccharide antibodies that bind to bacteria

Question 8

Toxoid Vaccines

Answer 8

• made from inactivated bacterial toxins
• target the toxin produced by certain bacteria, rather than the bacteria itself
• Bacterial toxic proteins are inactivated by formalin

Question 9

Viral Vector Vaccines

Answer 9

• uses a harmless virus (called a vector) to deliver genetic material into cells to produce an immune response
• strong immune response
• May already have immunity to viral vector

Question 10

Nucleic Acid Vaccines

Answer 10

• use genetic material (either DNA or RNA) to instruct cells in the body to produce a protein from the pathogen, which then triggers an immune response
• Nucleic acids produce an antigen
• Easy to develop and produce
• possibility that no immune response is generated or it is generated to nucleic acid or delivery vehicle
• no DNA vaccines in use currently

Question 11

Adjuvants

Question 12

Current Research: HIV Vaccines

Answer 12

• discovery of Broadly neutralizing antibodies (BnAbs) in some HIV infected patients that manage the disease better means we can target an immune response to develop/expand BnAbs conferring HIV immunity

Question 13

Summary of immune response to vaccination