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

Thank you