Wk 5 Vaccines

Question 1

What are 5 vaccine strategies?

Answer 1

1. Live vaccines: cross-reactive, attenuated (whole pathogen)
2. Inactivated (killed) vaccines w/ adjuvants (whole pathogen)
3. Sub-unit vaccine (partial pathogen): toxoid vaccines; recombinant protein vaccines; polysaccharide vaccines; conjugate vaccines
4. Vector vaccines: Adenovirus; Poxvirus
5. Nucleic acid vaccines: DNA; RNA

Question 2

What is a live vaccine?

Answer 2

Live organism efficiently stimulate innate and adaptive machinery. The best vaccines tend to be live. They also have the most adverse events.
Cross-reactive epitopes displayed by similar viruses (ie. cowpox and smallpox share some surface antigens, so immunization w/ cowpox induces Abs vs cowpox antigens, the Abs all bind and neutralize smallpox)

Question 3

Example of live vaccine

Answer 3

Smallpox

Question 4

Example of inactivated (killed) vaccine

Answer 4

polio

Question 5

What is an inactivated (killed) vaccine?

Question 6

Inactivated (killed) vs attenuated vaccines

Answer 6

Question 7

What type of vaccines need to be avoided in immunodeficient?

Answer 7

Live (ex oral polio - why we use injected - less effective)

Question 8

What is a subunit vaccine?

Answer 8

Anything that’s part of a pathogen, not all - usually a protein or polysaccharide

includes toxoid vaccines, recombinant, protein or polysaccharide

Question 9

What is a toxoid vaccine?

Answer 9

Only express portion (inert protein part), not the toxic
-keeps toxin from interacting with host cells
-produces Abs against the toxin

-tetanus and diptheria
-HepB (HBsAg) vaccines induces neutralizing Abs that target surface antigens

Question 10

What do polysaccharide sub-unit vaccines induce?

Answer 10

Marginal Zone B cells, which induces low affinity IgM - short-lived, migrate to inflammed tissues

-pneumococcus and meningococcus (both diplococci) (short-lived, 1-3 years)

Question 11

What is special about polysaccharide-specific B cells?

Answer 11

Live in the marginal zone of the spleen
Specialized for T-independent Ab responses
* No isotype switching: IgM only
* No affinity maturation
* No memory
* Many non-protein antigens that T cells can’t respond to

Question 12

Example of sub-unit vaccine?

Answer 12

Hep B

Question 13

What are conjugate vaccines?

Answer 13

Goal - produce long-lived IgG responses to polysaccharides

Question 14

What are conjugate vaccines?

Answer 14

Goal - produce long-lived IgG responses to polysaccharides

Question 15

How does conjugate work?

Answer 15

Conjugate polysaccharide and conjugate it to carrier protein
B cell has something to present on MHC Class II to T cells -> long-lived high affinity IgG

Question 16

What is meningococcal vaccine for?

Answer 16

polysaccharide vaccine that targets the 4 (of 6) main serotypes

Question 17

What are vector and nucleic acid vaccines?

Answer 17

SARS CoV-2

Question 18

Vector vaccine

Answer 18

Take replicating, live adenovirus, add protein you want to immunize against

Question 19

mRNA vaccines

Answer 19

Good for boosting secondary responses

Question 20

DNA vaccines

Answer 20

Hope bead will puncture a cell and induce RNA production

Question 21

What is an ajuvant?

Answer 21

Live viruses induce stronger inflammatory responses.
We want vaccines to produce bigger response w/o being live
Adjuvants produce macrophage activation, recruitment of inflammatory cells, cytokine production, prolonged inflammation (depot effect of oil-in-water emulsions)