CH 11: Vaccination

study questions plus explanations with questions

What is vaccination?

a deliberate delivery of weakened pathogen antigens that can cause a primary immune response but have little or no pathogenic potential

Explain what happens in our immune system when we get a vaccination:

Our immune system sees the weakened pathogen antigen as foreign; so it starts building defenses, like making memory B and T cell antibodies against the antigen. Those are made because the pathogen triggers an immune response because there is a live pathogen inside of our body.

What is the goal of vaccination?

to develop long-lasting immunological memory to the antigen in the vaccine

Explain the goal of vaccination:

vaccination creates a secondary immune response so then if you encounter the pathogen again, your body will be ready to respond with a secondary immune response to quickly kill and get rid of the already familiar pathogen. E

Example of vaccination- Flu vaccine

Flu antigens from the vaccine are introduced into your body.

Your immune system recognizes them as foreign and starts an immune response.

It creates antibodies and memory cells specific to those flu antigens.

Later, if exposed to the real flu virus, your immune system can respond faster and stronger, preventing you from getting seriously sick.

What is a live-attenuated vaccine?

A vaccine that consists of a live, but weakened pathogen

It is grown in cells of another species then given to humans to damper its strength

Why are live attenuated vaccine microbes grown in other cells then given to human cells?

This makes the microbe more adapted to growing in other cells so when it is injected into human cells it is weakened because it is out of its normal home and it won’t replicate as fast or be as aggressive.

What vaccine typically results in the strongest immune response?

Live attenuated vaccines

Why do live attenuated vaccines result in the strongest immune response?

Because the pathogen is alive (but weakened) it infects cells and replicates in the body as the natural pathogen would. Because of that, it activates all of the mechanisms of the immune response. W

What is a concern with live attenuated vaccines?

The pathogen has the ability to revert back to a pathogenic state in human cells

What is an inactivated vaccine?

a vaccine that uses a whole pathogen that has been killed by chemical or physical treatment.

How is an inactivated vaccine still able to elicit an immune response?

The pathogen, even though it is dead, still contains antigens that the body sees as foreign invaders. So an immune response is still produced to the foreign antigens.

Is the immune response produced from inactivated vaccines stronger or weaker than the immune response produced by live attenuated vaccines?

The response is weaker because the pathogen is dead, so the body is only responding how it would to foreign antigens not foreign pathogen antigens. The dead pathogen does not mimic a real pathogen response.

What vaccine is typically safest for immunocompromised individuals?

inactivated vaccines because the pathogen does not have the potential to revert back into a pathogenic state.

What is a subunit vaccine?

a vaccine that only uses select antigens from a pathogen, not the whole microbe itself

How does the subunit vaccine elicit an immune response?

It does not infect cells, but the body sees the antigens as foreign so they respond with a primary immune response.

What is one way live attenuated vaccines can be produced?

The pathogen can be grown in cells other than human cells. This allows for the pathogen to develop mutations that make it better adapted to species other than humans, therefore decreasing the pathogens ability to cause disease in human cells

What is another way live attenuated vaccines can be produced?

By taking a related strain of the virus that is non-pathogenic to humans and genetically modifying the virus to express proteins from the human strain of the virus. This helps generate immunological memory to the antigens/proteins present in the human strain.

What vaccine type is used mainly for viral vaccines?

Live attenuated

What is an adjuvent?

a substance that stimulates the immune system

What type of vaccine typically uses an adjuvent?

Subunit vaccines

Why do subunit vaccines typically use an adjuvent?

Because the antigen used in the vaccine may not contain PAMPs that would activate the innate immune system

without activation of the immune system then there is no activation of the adaptive immune system which means no memory response could form

What can an adjuvent contain to help stimulate an innate immune response?

It can contain natural PAMPs or chemically made PAMPs that will bind to PRRs and activate an innate immune response.

What vaccine types can cause side effects due to the body’s immune respone?

Live attenuated, subunit, and inactivated vaccines

Do infants produce strong TI-2 responses to encapsulated bacteria?

No they do not.

why do infants not produce strong TI-2 responses to encapsulated bacteria?

Infants have immature B cells and lack sufficient T cell helper support, which limits their ability to mount effective antibody responses to the carbohydrates in capsules.

(B cells recognize that carbohydrate in capsules and drive TI-2 responses)

How is the weak TI-2 response to encapsulated bacteria of infants combatted?

By giving a conjugate vaccine

What does a conjugate vaccine do to help infants strengthen their TI-2 response to encapsulated bacteria?

The vaccine consists of a capsular carbohydrate antigen attached to a protein. The B cells the infant does have will recognize the carbohydrate but the main part is the protein. The protein will be easier for the infant’s immune system to recognize. The protein will help activate T cells. Those T cells will then activate B cells to secrete antibodies and create immunological memory to the encapsulated bacterial pathogen.

What is herd immunity?

when a large majority of immune individuals (vaccinated or ones with developed memory response) protect a small minority of non-immune individuals (non vaccinated or those who do not have a memory response)

What does a strong herd immunity do?

It reduces the probability that non-immune individuals will encounter a specific pathogen because the chain of transmission is not really there.

Who does strong herd immunity protect?

Vulnerable people like infants to young to be vaccinated, kids who are not vaccinated, elderly, and those who are immunocompromised and not able to get vaccinated.