Immunity and vaccines Flashcards
Active immunity
When the immune system produces its own antibodies after being stimulated by an antigen
How can active immunity occur?
Naturally = after catching a disease from a pathogen
Artificially = injection of vaccine containing attenuated antigen
Passive immunity
When antibodies given to you from a different organism that your body did not produce naturally
How can passive immunity occur?
Naturally when a baby is given antibodies via mother’s breast milk/placenta
Artificially by being injected antibodies in a medicine such as antivenom
Passive vs active immunity
Active requires exposure to antigen whereas passive doesn’t
Active takes a while for antibody to develop whereas passive is instant
Active produces memory cells but passive does not
Active gives long term protection as a result but passive does not
Why use vaccines?
Because as the immune response occurs you suffer from the disease, which vaccines allow immune response with no disease + long term protection
What is in a vaccine?
An attenuated pathogen WITH ANTIGEN (GM to not cause disease)
Or RNA to encode for pathogen’s antigen by body cell
How do vaccines work?
Once antigen is injected, body will undergo humoral immunity response which produces memory B-cells that are complementary that if reinfected, can divide into plasma cells to produce specific antibodies complementary to antigen
Herd immunity
Reducing occurrence of pathogen if the majority of the population is vaccinated since it cannot be spread to even those unvaccinated
Ethical issues of vaccines
Animal testing
Using animal based products from blood
Testing on humans can be risky if they believe they are immune
Epidemic means choosing who’s vaccinated first
Antigenic variation
When antigens on surface of pathogen change due to changes in base sequence of primary structure in DNA/RNA
Causing change in tertiary structure
How can antigenic variation be a problem for vaccines?
Vaccines will produce memory cells against a specific antigen
By changing antigen, a new primary response will have to occur
