Passive Immunization and Vaccination

Question 1

Passive immunization

Answer 1

Transfer of pre-formed immunity (usually Abs) produced in one “individual” into another naive host

Two types:

Natural passive immunization - Ab from other to child through placenta (IgG) or in colostrum/breast mil (IgA)

Artificial passive immunization - transfer of mAb or polyclonal Ab (IVIG)

Question 2

Clinical uses of passive immunization

Answer 2

1. Prevent infectious disease progression after known exposure (i.e. needle stick w/ Hep B)
2. Ameliorate sxs of ongoing disease
3. Protect immunodeficient Pt’s who have been exposed to pathogen
4. Block toxin actions
5. Kill tumor cells (most widespread use of passive immunity)

Question 3

What molecules acts as the strongest immunogens?

Answer 3

Proteins - can be presented by MHC I and II

Question 4

What disease processes can be vaccinated against after exposure?

Answer 4

Hepatitis B or Rabies

Question 5

What vaccines induce the”best” most long-lasting immunity?

Answer 5

Attenuated live vaccines

Replicate within host

Some live-attenuated vaccine strains can cause severe disease in immunocompromised patients and are, therefore, contraindicated in the immunosuppressed, infants, and their close contacts.

Another disadvantage of these vaccines is that there is a low possibility that they can regain virulence via reversion mutations (i.e. polio live vaccine)

Question 6

Inactivated vaccines

Answer 6

Generally require multiple vaccinations to sustain immune response

Tend to induce a primarily humoral response w/ relatively low induction T-cell mediated responses

I.e. Rabies virus, Salk poliovirus and Sinopharm BBIBP SARS-CoV-2 vaccines

Question 7

Subunit vaccines

Answer 7

Purified pathogen protein or carbohydrate Ags

Elicit protective Ags - composed of a pathogen host cell0binding protein that elicits neutralizing Abs

I.e. Hep B and HPV vaccines

Question 8

Avirulent recombinant viral vector vaccines

Answer 8

Use a non- or less- pathogen virus vector (like adeonvirus or vaccinia virus) that has been genetically modified so that:

1. It does not replicate after infection of host cell
2. Expresses protein from other pathogens that will induce a protective adaptive immune response to those pathogens

i.e. J&J SARS-CoV-2 and rVSV-ZEBOV Ebola virus vaccines

Question 9

What types of pathogens are there conjugate vaccines available for?

Answer 9

Streptococcus pneumoniae

Hemophilus influenzae

Neisseria meningitidis

Good for encapsulated bacteria (i.e. those listed above)

Specifically designed to elicit opsonizing IgG to bacterial capsules?

Question 10

Which vaccine type is specifically designed to elicit opsonizing IgG to bacterial capsules?

Answer 10

Conjugate vaccines (becuase of IgG - carbohydrate subunit vaccines produce IgM)

Question 11

Answer 11

B. Revaccinating a member of the nursing staff against Hep B after a needle stick

Question 12

Answer 12

E. Smallpox

Close to eradicating polio

Question 13

Answer 13

A. Subunit vaccine