Vaccination Flashcards
Clinical correlation.
-young species = highly susceptible to infectious disease
-they dont have memory lymphocytes (naïveT & B cells)
-immunization prevents death from infectious diseases
Describe how modern vaccination begun.
-Edward Jenner noticed milkmaids rarely had smallpox due to prior infection with cowpox virus = immunity to small pox
-collected pus from lesion of cowpox in milkmaid & injected into boy ‘James Phipps’ = later infected him w small pox virus & boy survived
Describe the essentials of useful vaccines.
- Safe = doesnt cause illness/death (min side effects)
- Protective = prevents/reduced illness caused by pathogen
- Long lasting effects = sustained resistance
- Formation of protective antibodies = stim prod of antibodies reactive w antigenic epitopes
- Formation of protective T cells = stim prod of cell immunity (imp for intracellular pathogens)
- Others = low cost, stability, easy administration
Describe passive immunity.
-obtained by transfer of maternal antibodies to newborn
-administration of globulin fraction of serum (antiserum or antibodies)
-necessary during:
>primary/secondary immunodeficiency
>not possible for active immunity to develop/prevent disease
>infections where best immunity can only be provided by transfer of antibodies
Describe passive immunity in humans & its disadvantages.
Humans:
-rabies, botulism, diphtheria, measles, snake bite
Disadvantage:
-probability of hypersensitivity of type I or III
-immunity wanes w time & doesnt lead to memory
Describe how hyper immune serum is made.
-horse, goat, sheep for immunization
-serum collected from hyperimmunized animals
-immunoglobulins harvested from serum
-avoid immunogenicity from antibodies = cleaved to Fab2
Describe active immunity.
Acquired by:
-infection w pathogen
-vaccination w = attenuated vaccines, inactivated vaccines, subunits vaccines, recombinant vaccines
*GOAL = long term immunity w effector T & B cells to make memory
Describe the considerations for selecting a vaccine to induce active immunity.
-measurable IR = doesnt always mean protection
-vaccines can provide primary protection but may not leave immunological memory = not protective in long term
Describe the different types of vaccines.
• live-attenuated vaccines
• heat-killed/inactivated vaccines
• Subunit/component vaccines
• toxoid vaccines
• conjugate vaccines
• recombinant vaccines
• naked DNA vaccines
• vector vaccines
Describe live attenuated vaccines.
-live pathogen used as vaccine (ex. K9 distemper)
-non/less virulent form of pathogen (weakened)
-must replicate to be effective
-immunity w one dose (not oral tho)
-effective & induce longer lasting effect than killed vaccine
ADVANTAGES:
-replication of pathogen increases amount of antigen required to gen IR
-antigenic epitopes presented to induce T & B cells for antibody prod
Describe how attenuation is achieved - passaging.
- Passaging
-virulent pathogen cultured under conditions that dont support virulence
-EX: K9 parvovirus cultured in insect cells leading to loss of capability to effectively infect dog cells
>attenuated virus min infects dog
>if used as vaccine = wont cause disease but does induce protective IR
-EX: FluMis = vaccine against influenza virus replicated under low temp & cant replicate at 37c (can only replicate in URT)
Describe how attenuation is achieved - genetic engineering.
- Genetic engineering (modified vaccines)
-site directed mutagenesis or removing genes resp for virulence of a pathogens
-severe reaction possible
-must be stored properly
-interference from circulating antibody
Describe killed/inactivated vaccines.
-inactivated viruses, dead bacteria, killed pathogens that cant cause disease (EX: H3N8)
-retain immunogenicity
-heat, radiation, chemicals, antibiotics = methods used to kill
-cant replicate
-less interference from circ antibody than live vaccines
-require 3-5 doses
-IR mostly humoral
-antibody titer diminish w time
Describe subunit/component vaccines.
*made from purified antigens obtained from pathogens
1. Toxoids = (tetanus, diphtheria) purified toxins inactivated w formaldehyde but retain immunogenicity
-induces neutralizing antibodies
-genes encoding toxins are expressed in bacterial cells
2. Bacterial polysaccharides
-polysaccharides that cover the bacterial cell surface
-pathogenicity of bacteria depend on inhibition of phagocytosis by surface polysaccharides
-antibodies against polysaccharides can opsonize bacteria = efficient phagocytosis by neutrophils & macrophages
Describe recombinant vaccines.
-genes encoding immunogenic proteins cloned & expressed in prokaryotic or eukaryotic cells
Describe naked DNA vaccines.
-ID gene encoding immunogenic proteins
-clone gene & insert it into a plasmid vector
-plasmid DNA injected into animal
-DNA in cell gen mRNA from which the antigenic protein can be expressed
-antigen presented by DC to lymphocytes = IR
Describe vector vaccines.
-ID gene encoding immunogenic protein
-gene is cloned & inserted into vector (virus)
-recombinant virus serves as vector for inserted immunogenic protein
-vaccinated host infected w vector = doesnt cause disease but induces IR
Describe DIVA vaccines (marker).
differentiation of infection from vaccinated animals
-infections diagnosed by detection of serum antibodies as evidence of exposure
-discrimination between IR induced by vaccine VS natural exposure
Describe the 3 types of adjuvants.
- Antigen depot formation = slowly dissipate into intravascular tissue
- Antigen carrier effects = net pos charge of carrier attracts them to APCs = fuse w APC & incorporate antigens into antigen presentation pathways -> enhance IR
- Immune stim = adjuvant mol mimic PAMPs or DAMPs that bind to PRRs & activate APCs
Describe the adverse consequences of vaccinations.
DONT VACCINATE ILL/MEDICALLY IMMUNOSUPPRESSED ANIMALS
