Vaccines Flashcards
(12 cards)
What is immunization and what types are there?
- produce to increase concentration of antibodies and effactor T cells ( Protective against agents/cancer)
- Active: vaccines
- Passive: preformed anitbodies.
When was smallpox declared eradicated, and why was this possible?
Smallpox was eradicated through Jenner’s cowpox vaccine.
Compare passive vs. active immunization with examples.
Passive: Preformed antibodies (e.g., maternal IgG, rabies antitoxin).
Active: Induces immune memory (e.g., polio vaccine).
What are the key features of an effective vaccine?
Safe, protective, sustained immunity, induces neutralizing antibodies/T-cells, practical (low-cost, stable).
Why do inactivated vaccines (e.g., Salk polio) require boosters?
They elicit mainly humoral (antibody) responses without prolonged antigen exposure.
How do attenuated vaccines (e.g., Sabin polio, measles) provide long-term immunity?
Live pathogens replicate weakly, mimicking natural infection → robust cellular/humoral responses.
What is the risk of attenuated vaccines?
Reversion to virulence (e.g., Sabin polio back-mutation).
How are subunit vaccines (e.g., hepatitis B) produced?
Recombinant DNA technology (e.g., yeast-expressed HBsAg).
Name 2 adjuvants and their mechanisms.
-Alum: Delays antigen release.
-ISCOMs: Deliver antigens to cytosol for CTL responses.
How do DNA vaccines work?
Plasmid DNA encodes pathogen antigens → host cells express them, inducing cellular/humoral immunity.
What is a live recombinant vector vaccine? Give an example.
Engineered virus (e.g., vaccinia) carrying pathogen genes → expresses antigens (e.g., HPV L1 protein).
Why is the Sabin polio vaccine (OPV) more effective for eradication than IPV?
Induces gut IgA → blocks transmission; but rare reversion risks paralysis.
