Vaccines
description
Transcript of Vaccines
Vaccines
H.Sidra Yasin (BIOT 412)
Learning objectivesLearning objectives
What are the Methods to produce the vaccines
How we can modify the VaccinesWhat are the Routs of administration of
vaccinesWhat are the Types of vaccines
What is Reverse vaccinology and its purpose
Summary of all topics with conclusion
General Method to produce the General Method to produce the vaccinevaccine
Immunisation Department, Centre for Infections
Vaccine compositionVaccine compositionFollowing are:
Component Purpose Example
Adjuvants enhance the immune response to a vaccine
aluminium salts
Preservatives prevent bacterial or fungal contamination of vaccine
thiomersal
Additives stabilise vaccines from adverse conditions such as freeze-drying or heat, thereby maintaining a vaccine’s potency
gelatine
Residuals from manufacturing process
Inactivating agents
Antibiotics - prevent bacterial contamination during manufacturing process
Egg proteins- some vaccine viruses are grown in chick embryo cells
Yeast proteins
formaldehyde
neomycin, streptomycin, polymyxin B
influenza, yellow fever
HepB vaccine
Modifiers of vaccinesModifiers of vaccines
Modifiers of vaccinesModifiers of vaccines
AdjuvantsBoosters
AdjuvantsAdjuvants
Chemical substance that can be added to a vaccine in order to enhance the immune response to the vaccine.
TypesTypes
1. Freund’s Adjuvant
2. Aluminum Hydroxide3. Aluminum Phosphate (Alum)
BoostersBoosters
Periodic “booster” administration must be given in order to strengthen and lengthen the duration of immunity
Routs of administrationRouts of administration
RoutesRoutes Intradermal administration.
◦ Three types are; intravenous
intramuscular subcutaneous.
Oral administration.◦ Vaccine is usually given in
liquid form.◦ Foods
Intranasal administration.
Types of vaccinesTypes of vaccines
Types of vaccinesTypes of vaccines
Traditional Recombinant vaccines
1. TypesA. InactivatedB. Live C. Attenuated
2. Pathogens A. Bacteria B. Virus C. Parasites
1. Subunit Vaccines2. peptide vaccines3. Attenuated Vaccines4. Vector Vaccines5. Bacterial Antigen
Delivery Systems
Traditional vaccinesTraditional vaccines
Live, Attenuated VccinesLive, Attenuated Vccines
Act like natural infection Live, but weakened, viruses or bacteria Altered organisms, either genetically or
chemically but non pathogenic Example: Attenuated virus vaccine for yellow fever,
which utilizes the YF17D strain, a weakened form of the wild virus.
Live, Attenuated vaccinesLive, Attenuated vaccines
Advantages Disadvantages
• Single dose sufficient to induce long-lasting immunity
• Strong immune response • Local and systemic immunity • Others…Polio and Adeno
• Potential to revert to virulence• Contraindicated in
immunosuppressed patients• Interference by viruses or
vaccines and passive antibody
• Poor stability• Potential for contamination
Inactivated VaccinesInactivated VaccinesEither: Suspensions of whole intact killed
organisms ◦ e.g. whole cell Pertussis, Influenza, Rabies, HepA
Or: Acellular and sub-unit vaccines
◦ e.g. Acellular Pertussis vaccine contains between 2-5 components of the whole cell Pertussis bacteria
Inactivated vaccinesInactivated vaccines
1.whole 1.whole actual pathogen killed, either by a heat treatment or chemically Salk vaccine for polio, which utilizes whole
polioviruses that have been inactivated by formaldehyde.
2.Fractional2.Fractional
Protein based; ToxoidsProtein based; Toxoids Stimulates the antibody mediated response Exotoxins Toxoids are vaccines which consist of exotoxins Immunity against the toxins, but not necessarily the bacteria that produce
the toxins. Examples: Botulinum antitoxen Diphtheria antitoxen Pertusis Tetanus toxoids
Protein based; SubunitProtein based; Subunit Pathogenic agent Use components of pathogenic organism instead of whole
organism Advantage: no extraneous pathogenic particles i.e DNA Disadvantage: Costly Exampleso HSVMethod of productiono Tuberculosiso Foot -and-Mouth Disease virus (FMDV)
Polysaccharide based; purePolysaccharide based; pure
pure cell wall polysaccharide from bacteria
Polysaccharide based; conjugatePolysaccharide based; conjugate
Polysaccharide linked to a carrier protein More potent lacks long term immunological memory
Protect against: o Hibo Pneumococcal diseaseso Tetanuso Diphtheria
Inactivated vaccinesInactivated vaccines
Advantages Disadvantages
• Stable • Constituents clearly defined• Gives sufficient humoral
immunity if boosters given• No mutation or reversion• Can be used with immuno-
deficient patients
• Many vaccinees do not raise immunity
• Shorter lasting immunity • Boosters needed• Need several doses• Adjuvant needed• Failure in inactivation and
immunization with virulent viruses
• Others…
Possible Limitations of Traditional Vaccine Possible Limitations of Traditional Vaccine ProductionProduction
Not all infectious agents can be grown in culture
Animal/human cell culture expensive if needed
Yield of viruses from cultures can be low
Safety precautions for culture of live agents
Insufficient killing/attenuation of agents
Reversion of attenuated agents
Traditional vaccines are less diverse
New StrategiesNew Strategies
Delete virulence genes Use live nonpathogenic carriers for immunization
(unrelated pathogenic agent) Clone antigenic determinants into alternative host Address autoimmune system response/problems
So!!!So!!!
Recombinant vaccinesRecombinant vaccines
TypesTypes
1. Subunit Vaccines2. Peptide vaccines3. DNA Vaccines4. Vector Vaccines
Peptide vaccinesPeptide vaccines
Use discrete portion (domain) of a surface protein as Vaccine.
These domains are ‘epitopes’ antigenic determinants are recognized by antibodies
Use highly immunogenic carrier molecule
With carrier proteinsWith carrier proteins
DNA VaccinesDNA Vaccines DNA vaccines consist of plasmids that contains genes for
certain types of antigens. Once administered, the plasmid is taken up by the target
cell and the genes are expressed. The cell then either excretes the antigen or displays it on
an MHC-I molecule.
Genetic ImmunizationGenetic ImmunizationDelivery of a gene for the antigen to a host organism
• Use vector containing cDNA from viral protein/eukaryotic promoter
• Inject into muscle
POTENTIAL• Eliminates purification of antigen• Protein is modified post-translationally
Chimeric VaccinesChimeric Vaccines Consist of attenuated viruses have been engineered to
carry antigens from multiple types of pathogens. The yellow fever vaccine has been engineered to carry
antigens from HIV, different types of bacteria, malaria, even cancer.
immunity against several different diseases with one administration.
Human Diseases for Which Recombinant Vaccines Are Human Diseases for Which Recombinant Vaccines Are Currently Being DevelopedCurrently Being Developed
Vaccine Production methodsVaccine Production methods
Vaccine Production MethodsVaccine Production Methods
Manufacturing strategies:◦In-vivo◦In-vitro◦Chemical Synthesis
Some vaccines can be produced using any one of the three methods while for other vaccines, only one method will work.
In-VitroIn-Vitro Here, using recombinant
DNA technology, vaccines can be produced in yeast cultures, bacterial cultures, or cell cultures.
Recombinant vaccines, such as chimeric and Attenuated virus/bacteria vaccines, are produced in this manor.
In-VivoIn-Vivo
Embryonated Chicken eggs are commonly used as in producing flu vaccines.
Vaccines, like anti-idiotype, can also be produced in lab animals, such as mice.
There are even some species of plant, such as bananas, that have been genetically engineered to produce a vaccine.
Chemical SynthesisChemical Synthesis Produced in a lab.
Vaccines that utilize synthetic peptides as well as conjugated lipids and polysaccharides
Used in combination with either in-vivo or in-vitro production.
Summary!!!Summary!!!
Thank you!Thank you!