1. Syeda Hira 08-arid-1152 Ph.D (Biochemistry)
DNA VACCINES
Syeda Hira
08-arid-1152
Ph.D (Biochemistry)

2. Contents Introduction History Difference Production of DNA vaccines
Method of Delivery
Mode of Action
Advantages and Disadvantages
Future Perspective
Conclusion

3. Introduction Small circular piece of bacterial DNA.
Genetically Engineered to produce one or two specific protein from microorganism.
The 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.

4. History
In 1990, University of Wisconsin, Jon Wolff found that injection of DNA plasmids produce a protein response in mice
Since then concept of DNA vaccines started

5. Difference between DNA vaccine and Traditional vaccine
Traditional medicine
Uses weak or killed form of an infectious agent
Provide humoral immunity
DNA vaccines
Uses only the DNA from the infectious organism
Provide both humoral and cell mediated immunity

6. Preparation of DNA Vaccine
Viral gene
Recombinant DNA Technology
Expression plasmid
Plasmid with foreign gene

7. Transform into bacterial cell
Plasmid DNA
Bacterial cell

8. Plasmid DNA Purified
vaccine

9. DNA Vaccines: Optimization strategies
Plasmid optimization
Gene optimization
Formulation adjuvant
Immune plasmid adjuvant

10. Plasmid Optimization Plasmid vectors for use in vaccination contain
Promoter
Enhancer
Antigen-encoding
Polyadenylation sequences
Antibiotic resistance site

14. Gene Optimization Selection Requirements High GC content
Species-specific codon utilization
Consensus immunogens
Nuclear localization sequences

15. Formulation Adjuvants
Microsphere/nanoparticle
Liposomes
Polymers

16. Immune Plasmid Adjuvants
Cytokine
Chemokine
Co stimulatory molecules
Heat shock proteins

17. Methods of Delivery Intramuscular There are two methods
immunizations both directly transfected dendritic cells and macrophages can present antigen
i.m. immunizations are largely independent of DNA expression in the muscle target
intramuscular deliveries of DNA tend to raise type 1 T-cell help for intracellular and plasma membrane antigens but type 2 T-cell help for secreted antigens.

19. Continue… Gene Gun Method
Covering gold micro particles with recombinant DNA
Shoot them by gas pressure normally helium
gene gun immunizations directly transfected dendritic cells present antigens
Gene gun immunizations depend on antigen expression at the skin target 
Gene gun immunizations tend to raise type 2 T-cell help for both cell-associated and secreted antigens. 

20. The “gene gun”
The Helios Gene Gun is a new way for in vivo transformation of cells or organisms (i.e. gene therapy and genetic immunization (DNA vaccination)). This gun uses Biolistic ® particle bombardment where DNA- or RNA-coated gold particles are loaded into the gun and you pull the trigger. A low pressure helium pulse delivers the coated gold particles into virtually any target cell or tissue. The particles carry the DNA so that you do not have to remove cells from tissue in order to transform the cells.

22. Mechanism of Action The DNA vaccine works in two pathways. ENDOGENOUS
Antigenic Protein is presented by cell in which it is produced.
EXOGENOUS
Antigenic Protein is formed in one cell but presented by different cell.

23. ENDOGENOUS PATHWAY Nucleus Plasmid DNA MHC-I mRNA Antigenic Peptides
Antigenic Protein

24. T- Helper Cell
Multiply
Memory T cells

25. EXOGENOUS PATHWAY
Antigenic Protein come outside

26. Phagocytosed
Antigen Presenting Cell
Antigenic Peptides
Memory Antibodies
T- Helper Cell
Cytokines
Plasma B-Cell
MHC-II
Activated B-Cell
Memory B-Cell

27. WHEN VIRUS ENTER IN THE BODY
Memory T-Cell
Viral Protein
Antibodies

28. Advantages Elicit both humoral and cell mediated immunity
Plasmid vectors can be constructed and produced quickly  and the coding sequence can be manipulated in many ways.
Focused on antigen of interest
Stable for storage
Not require refrigeration
Another important advantage of genetic vaccines is their therapeutic potential for ongoing chronic viral infections

29. Disadvantages
Prolong immunostimulation may lead to chronic inflammation
Limited to protein Antigen only.DNA can be used to raise immune responses against pathogenic proteins, certain microbes have outer capsids that are made up of polysaccharides.  This limits the extent of the usage of DNA vaccines because they cannot substitute for polysaccharide-based subunit vaccines

30. Safety Issues Genetic toxicity
Integration of DNA vaccine into host Genome may result in
Chromosome instability, turn ON Oncogenes ,Turn OFF tumor Suppressor Genes
Over expression of DNA vaccine may cause acute or chronic inflammation and normal tissues destruction
Generation of autoimmune diseases
Resistance to antibiotics

31. Future Prospects
Plasmid with multiple genes provide immunity against many diseases in one booster
DNA Vaccines against infectious diseases such as AIDS, rabies, Malaria can be available

32. Conclusion
Simple ,safe and cheap alternative method for generation of humoral and cell mediated immunity
DNA Vaccines are in their early phase
DNA vaccines are going to be Vaccines of next generation

33. References
Widera, G., M. Austin, D. Rabussay, C. Goldbeck, S. W. Barnett, M. Chen, L. Leung,G. R. Otten, K. Thudium, M. J. Selby, and J. B. Ulmer Increased DNA vaccine delivery and immunogenicity by electroporation in vivo. J. Immunol. 164:4635– 4640.
John J. Donnelly,* Britta Wahren, and Margaret A. Liu DNA Vaccines: Progress and Challenges. J. Immunol. ; 175:
Donnelly, J. J., J. B. Ulmer, J. W. Shiver, and M. A. Liu DNA vaccines. Annu. Rev. Immunol. 15: 617– 648.
Tang, D.; Devit, M.; Johnston, S.A.; Others Genetic immunization is a simple method for eliciting an immune response. Nature 356 (6365): 152–154. 
Michele A. Kutzler* and David B. Weiner DNA vaccines: ready for prime time? Nature Reviews. 9:
M. A. LIU. DNA vaccines J. Internal Medicine. 253: 402–410.
Siddhesh D. Patil,1 David G. Rhodes,1 and Diane J. Burgess DNA-based Therapeutics and DNA Delivery Systems: A Comprehensive Review. AAPS Journal. 7:61-77.