Vaccines Flashcards
what is the basis for vaccination?
lymphocyte memory
describe the lymphocyte memory/adaptive immune response that is the basis for vaccination (include primary and secondary exposure)
- the primary adaptive immune response is very delayed (10-14d). IgM is secreted first and then IgG
- the secondary exposure yields a response that is much faster (pathogen cleared in approx 3 days) and there is an immediate IgG peak
what are the 2 types of immunization to prevent disease?
- active: vaccination
2. passive: antibody transfer
describe passive immunization via antibody transfer
transfer of immunity from protected individual to susceptible individual
what kind of protection does passive immunization via antibody transfer offer? (2)
- immediate but
2. only temporary
why is passive immunity gained from antibody transfer only temporary? how long last?
cells are not transferred, so more antibodies cannot be made once the transferred antibodies have circulated out of the body, lasts only 2-3 weeks
describe active immunity gained from vaccination; give an added benefit as compared to passive immunity
administration of antigen so susceptible individual mounts their own immune response; will be able to clear antigen quickly upon a secondary exposure
what kind of protection does active immunity via vaccination offer? (2)
- delayed protection but
2. more longterm protection than antibody transfer; the exact time depends on the antigen
give the process of antibody transfer
- administration of antigen to one individual so that individual produced antibodies
- collect plasma and purify antibodies
- Fc portion of antibodies cleaved off, leaving only Fab portion (called immune globulin) to prevent immune response to antibodies
- immune globulins are transferred to another individual for immediate protection
what animals are often used to produce antibodies for antibody transfer and why?
horses; they are large so you can safely collect more blood to be transferred to others
what are the two major types of vaccines used in animals that work woth whole pathogens?
- killed
2. live
how do killed vaccines work?
the pathogen is inactivated (killed) and administered to the animal so the animal produces its own immune response to the pathogen
what must be considered when working with killed vaccines?
must not drastically alter the pathogen in killing it, or will not elicit and effective immune response
how do live vaccines work?
atteunate (modify) the pathogen but keep it alive and administer to animal to cause immune response
what must be considered when working with live vaccines?
you may get a more appropriate immune response if the pathogen is allowed to act normally in the body, but this vaccine type may also cause disease as the animal fights it off
how are viruses usually attenuated for live vaccines?
they are cultured in cells of animals that they are not specifically pathogenic for, and then the mutated version is what will be administered in the vaccine
what are the 6 kinds of vaccines that only work witha portion of the pathogen and are not as common in animals?
- toxoid vaccines
- subunit vaccines
- conjugate vaccines
- recombinant vector vaccines
- DNA vaccines
- mRNA vaccines
what are toxoid vaccines used against?
used against pathogens that produce toxins
what is a toxoid?
inactivated toxin that is administered to animals to elicit an immune response
give example of toxoid vaccine
tetanus vaccine
how do subunit vaccines work?
an antigen is isolated from a virus (often an adhesion molecules) and that antigen is used in the vaccine to produce memory cells and antibodies against that PART of the virus
what is a benefit of subunit vaccines?
they are very safe and do not cause infection
how do conjugate vaccines work?
2 antigens from the same pathogen (one weak and one strong) are combined and administered in order to produce more memory cells)
how do recombinant vector vaccines work?
they use harmless bacteria or an attenuated virus to express pathogenic antigen, basically a gene from a bad pathogen is incorporated into a les bad pathogen that won’t cause as much damage
give an example of a recombinant vector vaccine
Johnson and Johnson COVID vaccine
how do DNA vaccines work?
isolate a gene from a pathogen and inject it into a plasmid, then inject the plasmid into an animal to elicit a response
how do mRNA vaccines work?
basically the same as DNA vaccines with the plasmid, only since mRNA is injected instead of DNA, host cells only have to translate the mRNA into proteins instread of transcribing and translating
what are adjuvants?
additives that maximize the effectiveness of vaccines
what are the 3 groups of adjuvants
- depot adjuvants
- particulate adjuvants
- immunstimulatory adjuvants
what are depot adjuvants?
protect antigen from rapid degradation and prolong theimmune response, allowing for B and T cell activation and memory development
what are particulate adjuvants?
effectively deliver antigen to APCs
what are immunostimulatory adjuvants?
molecules that enhance cytokine production and direct the immune response to different helper T cell responses
how are adjuvants often used?
in combination with each other for more or specific effects; usually a depot or particulate with an immunostimulatory
give the 4 most common routes of delivery of vaccines
- intramuscular
- subcutaneous
- oral
- intranasal
give 5 less common routes of delivery for vaccines
- intraocular
- intraperitoneal
- intrathecal
- intracranial
- immersion
how is vaccine efficacy measure?
as the preventable fraction
give the formula for preventable fraction for a vaccine
(% unvaxxed that contract disease - % vaxxed that contract the diease) divided by % unvaxxed that contract the diease
when is a vaccine considered effective?
when the preventable fraction is at least 80%
what is the whole goasl of vaccination?
to establish herd immunity
