1 syeda hira 08-arid-1152 ph.d (biochemistry) dna vaccines
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Syeda Hira 08-arid-1152Ph.D (Biochemistry)
DNA VACCINES
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Contents
• Introduction
• History
• Difference
• Production of DNA vaccines
• Method of Delivery
• Mode of Action
• Advantages and Disadvantages
• Future Perspective
• Conclusion
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.
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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
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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
Preparation of DNA Vaccine
Viral gene
Expression plasmid
Plasmid with foreign gene
Recombinant DNA Technology
Bacterial cell
Transform into bacterial cell
Plasmid DNA
Plasmid DNA Purified
vaccine
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DNA Vaccines: Optimization strategies
1. Plasmid optimization
2. Gene optimization
3. Formulation adjuvant
4. Immune plasmid adjuvant
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Plasmid Optimization
Plasmid vectors for use in vaccination contain
• Promoter
• Enhancer
• Antigen-encoding
• Polyadenylation sequences
• Antibiotic resistance site
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Gene Optimization
• Selection Requirements
High GC content
Species-specific codon utilization
Consensus immunogens
Nuclear localization sequences
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Formulation Adjuvants
Microsphere/nanoparticle
Liposomes
Polymers
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Immune Plasmid Adjuvants
Cytokine
Chemokine
Co stimulatory molecules
Heat shock proteins
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Methods of Delivery
There are two methods
Intramuscular 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.
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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.
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.
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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.
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mRNA
Antigenic Protein
Antigenic Peptides
MHC-I
Plasmid DNA
Nucleus
ENDOGENOUS PATHWAY
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Multiply
Memory T cells
T- Helper Cell
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EXOGENOUS PATHWAY
Antigenic Protein come outside
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Phagocytosed
Antigen Presenting Cell
Antigenic Peptides
T- Helper Cell
Cytokines
Activated B-Cell Memory B-Cell
Plasma B-Cell
Memory Antibodies
MHC-II
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WHEN VIRUS ENTER IN THE BODY
Viral Protein
Memory T-Cell
Antibodies
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
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
Safety Issues
Genetic toxicity Integration of DNA vaccine into host Genome may result inChromosome 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
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
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
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. 2000. Increased DNA vaccine delivery and immunogenicity by electroporation in vivo. J. Immunol. 164:4635– 4640.• John J. Donnelly,* Britta Wahren, and Margaret A. Liu.2005. DNA Vaccines: Progress and Challenges. J. Immunol. ; 175: 633-639.•Donnelly, J. J., J. B. Ulmer, J. W. Shiver, and M. A. Liu. 1997. DNA vaccines. Annu. Rev. Immunol. 15: 617– 648.•Tang, D.; Devit, M.; Johnston, S.A.; Others. 1992. Genetic immunization is a simple method for eliciting an immune response. Nature 356 (6365): 152–154. •Michele A. Kutzler* and David B. Weiner. 2008. DNA vaccines: ready for prime time? Nature Reviews. 9: 777-788.•M. A. LIU. DNA vaccines. 2003. J. Internal Medicine. 253: 402–410.•Siddhesh D. Patil,1 David G. Rhodes,1 and Diane J. Burgess. 2005. DNA-based Therapeutics and DNA Delivery Systems: A Comprehensive Review. AAPS Journal. 7:61-77.
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