Vaccines Flashcards
passive immunization
passive transfer of antibodies that can be used to provide SHORT term protection to an immunocompromised or naive animal
transfer of antibodies generated from an immunized animal
RAPID protection - gives antibody directly
active immunization
transfer of a killed pathogen to an animal in order to generate antibodies in response
provides LONGER term protection
mounting own immune response is SLOW - takes longer
what is the goal of vaccination
generate artificial memory
goal is to generate the same immune response to a pathogen as if the animal were naturally infected but without virulence
vaccine acts as the primary infection resulting in generation of effector T and B cells that are IMMEDIATELY infective
viral neutralization
generation of high affinity IgG and IgA that block the virus from binding to cell surface receptors
what are the components of the vaccine
requires all 3 signals for lymphocyte activation
vaccine signal 1
antigen
either pathogen protein or entire organism
vaccine signal 2
adjuvant providing co-stimulation
signals inflammation
vaccine signal 3
adjuvant providing proper cytokine release (signals differentiation)
do live attenuated vaccines require adjuvant
no - provides all 3 signals without an adjuvant because pathogen is active
opsonization
antibodies coat the pathogen via the front end and bind to Fc receptors on macrophages via the back end leading to phagocytosis of pathogen
depot effect
delaying release of antigen to the immune system
goal is to mimic a real infection - do not want antigen to only be present for a short time then get cleared too quickly
how does adjuvant stimulate innate immune system
activates TLRs, CLRs, or cytosolic sensory receptors
initiates innate immune response required to yield an inflammatory response
how does adjuvant get delivered into the cell cytosol
vaccine mimics and intracellular pathogen to induce an MHC I response
alum adjuvant
very safe adjuvant; induces a strong antibody response but weak CD8 T cell response
antigen depot - antigens absorb aluminum salts and become particulate that slowly releases into solution
MOA of alum adjuvant
- alum binds lipids on DC surface
- moves lipids around and triggers intracellular signaling pathway
- activates DC to phagocytose the antigen in the vaccine
- DC migrates to LN and provides signal 1, 2, 3 to activate T cells
live attenuated vaccines
weakened form of the virus
- generates most appropriate immune response
- can be difficult to do safely
killed pathogen vaccine
modified virus that has been inactivated
- less appropriate CD4 and CD8 T cell responses
- safer, will not cause disease
inactivated toxoid vaccine
toxin produced by the virus that has been inactivated
- less appropriate CD4 and CD8 T cell responses
- safer, will not cause disease
subunit/conjugated vaccine
proteins expressed by the pathogen that are not virulence factors
- can be effective if target antigens are known
- antibody response is critical
spontaneous live attenuated vaccine
isolating the pathogenic virus on a cell culture from intended species and using it to infect a cell line of a related species –> virus mutates to infect new species –> virus no longer grows on original species cells
not controlled –> can not regulate what the mutations are and if they are safe or effective
viruses can revert back to original type
recombinant DNA vaccine
modifying the virus by directly deleting the virulence gene from the genome
controlled version of spontaneous live attenuated vaccines
- ensures virus is unable to revert back
- requires a way that host cells can take up and use the foreign DNA
DIVA vaccine
used to differentiate infected vs vaccinated animals
delete a nonessential gene in a vaccine strain –> inject into animal –> test antibodies on ELISA
function of parabiosis
determine whether circulating or resident memory T cells are more important in response
core vaccines
required vaccines for diseases with significant morbidity, mortality, wide distribution, or public health risk
required for all animals with known or unknown vaccination history
non core vaccines
“elective” vaccines recommended based on geography, age and lifestyle
recommended for at risk animals
when do you start vaccinating puppies
6 to 8 weeks old
window of susceptibility
period of time between 6 and 8 weeks of age during which the puppy has too much circulating maternal antibody that will block vaccines, but not enough to block viral infection
want to vaccinate at start of window of susceptibility to include any outlier puppies
- continue vaccinating regularly until circulating maternal antibodies falls to zero (15 weeks)
minimum and maximum vaccination interval between boosters
minimum: 2 weeks
maximum: 6 weeks
need primary immune response to drop off before giving the second vaccine
juvenile initial series
small animals: vaccinate every 3-4 weeks
large animals: vaccinate every 4-6 weeks
what age do you vaccinate until in juveniles
16-20 weeks old
may require additional vaccine at 6 months or 1 year old
adult initial series
used in adults w/ no or unknown vaccine history
inactivated: every 2-3 weeks for 2-3 total vaccines
live attenuated: one may be sufficient
how often do you vaccinate post initial series
inactivated: annual (except rabies)
live attenuated: every 2-3 years
autogenous vaccines
taking a pathogen from a sick animal on specific farm and creating a vaccine from it to vaccinate healthy animals on that farm
does not have as many safety checks - only use when there is either no appropriate vaccine available or available vaccine does not work
vaccine failure
animal still gets clinical disease despite being vaccinated
caused by:
- vax during window of susceptibility
- lack of booster vaccination
- non-responder
- overwhelming challenge
- strain not covered
- immunosuppressed animal
expected adverse effects
side effects caused by generating a proper immune response
general: lethargy, anorexia
localized: pain, swelling, erythema, irritation, abscess, alopecia
caused by innate response
unexpected adverse effects
side effects caused by generating an improper immune response
- allergic reactions
- injection site sarcomas
allergic reactions
anaphylaxis
type I hypersensitivity that happens immediately
