DNA VACCINESDNA VACCINESCompiled byCompiled by

Dr. Taruna Anand, Scientist

VTC, NRC Equine, Hisar (Haryana)-India

Dr. Dharmendra Kumar, Scientist

CIRB, Hisar (Haryana)- India

&

Divya Kamboj (B. Sc)

What is immunity ?What is immunity ?

Mechanisms used by our body to fight Mechanisms used by our body to fight against antigensagainst antigens

Immunization is done to generate immunityImmunization is done to generate immunity

Passive Vs Active ImmunityPassive Vs Active Immunity

Passive immunization is immunotherapy Passive immunization is immunotherapy (transfer of antibodies)(transfer of antibodies)

Active immunization is immunity due to Active immunization is immunity due to natural infections or vaccinesnatural infections or vaccines

Passive ImmunizationPassive Immunization

Lasts as long as antibodies are present

Does not establish memory

Vaccines Provide Active ImmunityVaccines Provide Active Immunity

Vaccines provide active immunity & hence Vaccines provide active immunity & hence protect from diseases by establishing protect from diseases by establishing memory memory TT & & BB cells cells

Some vaccines prevent disease but do not Some vaccines prevent disease but do not cause infectioncause infection

What are Vaccines?What are Vaccines?

Preparations of materials such as virus or bacteria which are injected into a person to provide immunity against a particular disease

TYPES OF VACCINESTYPES OF VACCINES

VACCINES EXAMPLES

Attenuated (live) vaccines eg: Measles, Mumps & Rubella virus vaccine

Inactivated (killed) vaccines Influenza virus vaccine & Polio vaccine

Polysaccharide vaccines Pneumococcal pneumonia

Toxoid vaccines Tetanus vaccine

Recombinant vaccines Hepatitis B vaccines

DNA vaccines Influenza virus vaccine

It consists of a DNA molecule, generally a plasmid, with a gene that codes for the protein against which an immune response is desired.

DNA vaccines are actually made up of a modified form of an infectious organism’s DNA.

What is a DNA Vaccine?What is a DNA Vaccine?

Genetic ImmunizationGenetic Immunization

Vectors for DNA vaccinesVectors for DNA vaccines

Plasmid backbone Transcription unit comprising a strong viral

promoter / enhancer sequences. Antibiotic resistance gene

DNA Vaccine PlasmidDNA Vaccine Plasmid

Site of DNA Vaccine DeliverySite of DNA Vaccine Delivery

SubcutaneousSubcutaneous Intramucosal (nasal, tracheal) Intramucosal (nasal, tracheal) IntramuscularIntramuscular Intradermal Intradermal

Mechanism of ActionMechanism of Action

ApplicationsApplications

DNA vaccines used to prevent influenza in DNA vaccines used to prevent influenza in animalsanimals

DNA vaccine being developed for diseases DNA vaccine being developed for diseases such as HIV, tuberculosis and malaria.such as HIV, tuberculosis and malaria.

AdvantagesAdvantages

Evoke both humoral & cell mediated Evoke both humoral & cell mediated immune responsesimmune responses

Large scale manufacturing procedures Large scale manufacturing procedures availableavailable

Longer shelf life (thermostable)Longer shelf life (thermostable) Allows a more simplified & effective control Allows a more simplified & effective control

process.process.

Concerns & Potential DisadvantagesConcerns & Potential Disadvantages

The potential for integration of the DNA into the The potential for integration of the DNA into the host chromosomeshost chromosomes

Possibility of generating Ab to DNAPossibility of generating Ab to DNA Risk of effecting the expression of genes Risk of effecting the expression of genes

controlling cell growthcontrolling cell growth Unsuccessful when evaluating non protein based Unsuccessful when evaluating non protein based

Ag such as bacterial polysaccharideAg such as bacterial polysaccharide

Future ProspectsFuture Prospects

The relative ease of development & production as well The relative ease of development & production as well as their efficacy in animal models make DNA vaccines as their efficacy in animal models make DNA vaccines an attractive mode of treatment & investigationan attractive mode of treatment & investigation

While not all safety concerns have been completely While not all safety concerns have been completely addressed, human trials in HIV patients are addressed, human trials in HIV patients are encouragingencouraging

DNA vaccination shows promise in a no. of areas DNA vaccination shows promise in a no. of areas including infectious diseases, allergy & cancer including infectious diseases, allergy & cancer immunotherapiesimmunotherapies

Thank youThank you