dna vaccine
DESCRIPTION
Dna vaccine and its whole mechanisms, and future aspectsTRANSCRIPT
DNA VaccineSmit Banker
Government science college
ContentIntroductionHistoryTypes of vaccineHow DNA vaccines are madeDelivery methodMechanism of actionAdvantageDisadvantageFuture of DNA vaccine
IntroductionDNA vaccine is DNA sequence used as a
vaccine.This DNA Sequence code for antigenic
protein of pathogen.As this DNA inserted into cells it is translated
to form antigenic protein. As this protein is foreign to cells , so immune response raised against this protein.
In this way ,DNA vaccine provide immunity against that pathogen.
HistoryIn 1990, University of Wisconsin, Jon Wolff
found that injection of DNA plasmids produce a protein response in mice.
In 1993, Merck Research Laboratories, Dr. Margaret Liu found that intramuscular injection of DNA from influenzae virus into mice produced complete immune response
In 1996, trials involving T-cell lymphoma, influenzae & herpes simplex virus were started
DNA vaccines Vs Traditional vaccines
» Uses only the DNA from infectious organisms.
» Avoid the risk of using actual infectious organism.
» Provide both Humoral & Cell mediated immunity
» Refrigeration is not required
» Uses weakened or killed form of infectious organism.
» Create possible risk of the vaccine being fatal.
» Provide primarily Humoral immunity
» Usually requires Refrigeration.
DNA vaccines Traditional vaccines
Types of vaccine
3.1 FIRST GENERATION VACCINES Are whole-organism vaccines – either live and
weakened, or killed forms.
Live, attenuated vaccines, such as smallpox and polio
vaccines, are able to induce killer T-cell (TC or CTL)
responses, helper T-cell (TH) responses and antibody
immunity.
However, there is a small risk that attenuated forms of a
pathogen can revert to a dangerous form, and may still
be able to cause disease in immunocompromised people
(such as those with AIDS).
Second generation vaccinesecond generation vaccines were developed to minimize
the risks of the live attenuated vaccines.
protein antigens (such as tetanus or diphtheria toxoid)
or
recombinant protein components (such as the hepatitis
B surface antigen).
These, too, are able to generate TH and antibody responses,
but not killer T cell responses.
Third generation vaccineDNA vaccines are third generation vaccines, and
are made up of a small, circular piece of bacterial DNA (called a plasmid)
The vaccine DNA is injected into the cells of the body, where the "inner machinery" of the host cells "reads" the DNA
and converts it into pathogenic proteins.
Because these proteins are recognized as foreign, when they are processed by the host cells and displayed on their surface, implies;
the immune system is alerted, which then triggers a range of immune responses.
DNA vaccine is made
Viral gene
Recombinant DNA Technology
Expression plasmid
Plasmid with foreign gene
Transform in to bacteria
Plasmid DNA get Amplified
Plasmid DNA isolated
Stored in vials
Ready for Apply
Methods of deliveryInjection: Large amount of DNA
vaccines applied directly to the skeletal tissues.Gene Gun: Small amount of vaccine
applied through DNA coated gold beads
to the abdominal skin.Pneumatic Jet Injection: Very high amount
of vaccine applied to the abdominal skin.
How DNA vaccines work?BY TWO PATHWAYSENDOGENOUS :- Antigenic Protein is presented by cell
in which it is produced.
EXOGENOUS :- Antigenic Protein is formed in one cell but presented by different cell.
mRNA
Antigenic Protein
Antigenic Peptides
MHC-I
Plasmid DNA
Nucleus
Endogenous Pathway
Multiply
Memory T cells
T- Helper Cell
EXOGENOUS PATHWAY
Antigenic Protein come outside
Phagocytosed
Antigen Presenting Cell
Antigenic Peptides
T- Helper Cell
Cytokines
Activated B-Cell Memory B-Cell
Plasma B-Cell
Memory Antibodies
MHC-II
When Virus Enter in the Body
Viral Protein
Memory T-Cell
Antibodies
Advantages Vaccination with no risk for infection.Immune response focused only on antigen of interest.Stability of vaccine for storage and shippingCost-effectiveness.Long-term persistence of immunogen.Elicit both Humoral & cell mediated immunityRefrigeration is not requiredStable for storage
DisadvantagesLimited to protein immunogens.
Risk of affecting genes controlling cell growth.
Possibility of inducing antibody production against DNA.
Possibility of tolerance to the antigen (protein) produced.Limited to protein immunogens (not
useful for non-protein based antigens such as bacterial polysaccharides)
Future of DNA vaccinePlasmid with multiple genes provide immunity against
many diseases in one booster.DNA vaccines against infectious diseases such as AIDS,
Rabies, Malaria can be available.In future DNA vaccines can be applied to boost up the
immune system.
References
> www.medscape.com> www.wikipedia.org> www.sciencedirect.com> www.nature.com> www.biokenyon.com> www.biolife.com Immunology by Kuby 6th Edition
Immunology by Tizard 4th Edition
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