Vaccination and Immune Memory - Anatomy and Physiology
- Why are live attenuated vaccines usually avoided in severely immunocompromised people?
- The weakened pathogen can still replicate and may cause disease when immune defenses are poor.
- How does an mRNA vaccine produce immunity?
- Host cells translate the mRNA into a pathogen protein, which the immune system recognizes as an antigen.
- What is the purpose of a booster dose of a vaccine?
- It triggers a secondary response, raising antibody levels and expanding memory cell populations.
- Which antibody class predominates early in a primary immune response?
- IgM, which is produced first, followed by a switch to IgG.
- A snakebite victim receives antivenom containing ready-made antibodies. Which type of immunity is this?
- Artificially acquired passive immunity. It acts immediately but gives no memory.
- Why is passive immunity short-lived?
- The transferred antibodies are gradually broken down, and no memory cells are formed.
- How does a secondary immune response differ from a primary response?
- It is faster, larger and longer lasting, with mainly IgG antibodies of higher affinity.
- Which type of immunity does vaccination produce?
- Artificially acquired active immunity: the body makes its own antibodies and memory cells in response to the vaccine antigen.
- What is herd immunity?
- Indirect protection of unvaccinated people when enough of the population is immune that the pathogen cannot spread easily.
- Which cells give long-term immunological memory after vaccination?
- Memory B cells and memory T cells, which respond rapidly on later exposure to the same antigen.
- Which type of immunity does a fetus receive from maternal IgG crossing the placenta?
- Naturally acquired passive immunity, because the antibodies were made by the mother.
- What is a toxoid vaccine?
- A vaccine made from an inactivated bacterial toxin, such as tetanus toxoid, which induces antibodies against the toxin.