Vaccines

What is an antigen?

An antigen is an antibody generator, a substance usually part of a pathogen that the immune system recognizes as foreign and responds to by making antibodies.

How can one antigen give rise to more than one antibody?

One pathogen can have many different antigens, and one antigen can have smaller regions called epitopes. Different regions on the same bacteria or virus can trigger different antibodies, leading the immune system to make multiple antibodies against various parts of the same pathogen.

What is the main idea behind administering a vaccine?

The main idea is to introduce an antigen in a safe form so the immune system can respond without the person getting the disease, allowing the body to make antibodies and memory cells for a faster response to future infections.

What is active immunity?

Active immunity occurs when the body is exposed to an antigen and makes its own antibodies and memory cells, providing long-term protection.

What is passive immunity?

Passive immunity occurs when a person is given antibodies directly, leading to short-lived protection as the body does not create memory cells.

What is naturally acquired immunity?

Naturally acquired immunity happens through natural exposure, such as getting infected or receiving antibodies from mother to baby.

What is artificially acquired immunity?

Artificially acquired immunity occurs through medical interventions, such as vaccinations or receiving antibody treatment.

What are important characteristics of a good vaccine?

A good vaccine should be safe, cause a strong immune response, produce memory cells, give long-term protection, prevent disease without causing illness, and be easy to administer and stable for storage.

What is the primary antibody response?

The primary response happens the first time the body sees an antigen; it is slower and weaker as the immune system must recognize the antigen and activate the correct cells.

What is the secondary antibody response?

The secondary response occurs after re-exposure to the same antigen, being faster, stronger, and longer-lasting due to the presence of memory cells.

What is a live attenuated vaccine?

A live attenuated vaccine contains a weakened form of the pathogen.

What is a killed/inactivated vaccine?

A killed/inactivated vaccine contains a dead pathogen.

What is a subunit vaccine?

A subunit vaccine contains only part of the pathogen, such as a protein.

What is a toxoid vaccine?

A toxoid vaccine contains an inactivated toxin.

What is an mRNA vaccine?

An mRNA vaccine gives instructions for cells to make a harmless antigen.

What is a viral vector vaccine?

A viral vector vaccine uses a harmless virus to deliver antigen instructions.

What is herd immunity?

Herd immunity occurs when enough people in a population are immune, making it difficult for the pathogen to spread, thus protecting those who cannot be vaccinated.

Goal of a vaccine

to make memory T cells

features of a vaccine

safe, protective, cheap, sustained protection, induces protective t cells