Gene Vaccine Dr. Sina Soleimani Human Viral Vaccines Quality Control Laboratory (HVVQC)
Titles 1. A short Introduction of Vaccine History 2. First Lineage of Vaccines 3. Second Lineage of Vaccines 3. New Lineage of Viral Vaccines 3-1- Production 3-2- Protection 3-3- Inoculation 3-4- Advantage 3-5- Disadvantage
History of Vaccines production century Live attenuated Killed whole organism Purified protein or polysacharide Genetically engineered 18 Small pox(1798) 19 Rabies(1885) Rinder pest(1897) Yellow fever(1935) Rabies (new)(1967) Haemophilus Influenza Hepatitis B (Recombinant) (1980) (1986) 20 Measles(1960) IPV(1955) Hepatitis B (plasma derived)(1976) OPV(1962) Japanese encephalitis(1970) Rubella(1964) Hepatitis A Mumps(1967)
Properties of an ideal vaccine 1. 100% safe 2. Do not cause disease in others 3. No residual pathogenicity 4. Will prevent disease 5. Effective against all strains 6. Only one dose required 7. Compatibility with other vaccines 8. Indefinite room temperature storage 9. Cheap to manufacture 10. Capable of inducing effective herd immunity
First lineage of Vaccines 1. Inactivated (Killed) IPV, Rabies, Japanese Encephalitis B, Hepatitis A 2. Attenuated (Live) OPV, MMR, Yellow Fever, Varicella Or cross-reactive strains, e.g., vaccinia virus (cowpox) protects against smallpox 3. Toxoid diphtheria, tetanus
First lineage of Viral Vaccines (con.) 4. Acellular components Purified polysaccharides or proteins New pertussis vaccine (Bordetella pertussis components) 5. Conjugate vaccines poorly immunogenic component bound to protein (capsular polysaccharide from H. influenzae bound to e.g., diphthera toxoid)
Advantages of Attenuated Vaccines 1. Activates all phases of immune system. Can get humoral IgG and local IgA 2. Raises immune response to all protective antigens. 3. More durable immunity; more cross-reactive 4. Low cost 5. Quick immunity 6. Easy administration (In case of Polio and Adeno vaccines) 7. Easy transport in field 8. Can lead to elimination of wild type virus from the community
Disadvantages of Live Attenuated Vaccine 1. Mutation; reversion to virulence (often frequent) 2. Spread to contacts of vaccine who have not consented to be vaccinated (could also be an advantage in communities where vaccination is not 100%) 3. Spread vaccine not standardized--may be back-mutated 4. Poor "take" in tropics 5. Problem in immunodeficiency disease (may spread to these patients)
Advantages Inactivated Vaccines 1. Gives sufficient humoral immunity if boosters given 2. No mutation or reversion 3. Can be used with immuno-deficient patients 4. Sometimes better in tropics Disadvantages 1. Many vaccines do not raise immunity 2. Boosters needed 3. No local immunity (important) 4. Higher cost 5. Failure in inactivation and immunization with virulent virus
Second Lineage of Vaccines (Recombinant Vaccines) By Viral Genome Sequencing & cloning and by Recombinant DNA Technology with Genetic engineering 1. Live Recombinant Vaccine 2. Recombinant Vector Vaccine 3. Sub unit Vaccine (Protein Recombinant Vaccine) 4. Anti Idiotype Vaccine 5. Synthetic peptide vaccines
1. Live Recombinant Vaccine Production of Attenuated live Vaccine With Mutation in Virulance Gene VEE Vaccine
2. Recombinant Vector Vaccine Isolation of Immunogen gene from pathogenic organism Transfer of Gene to Virus or Bacterial Vector (live without virulance such as Vaccinia, Polio, Adenovirus, Salmonella) Propagation of vector Immunogen protein synthesis stimulate an immune response against the specific protein Main Problem: Disease in Immunodificiency
RECOMBINANT VECTOR VACCINE Advantages: 1. Risk Elimination of reversion to virulence 2. Both CMI and Humoral Immunity (If the vector is capable of intracellular replication) Disadvantages: 1. Weak CMI response ( If vector is incapable of intracellular replication) 2. Very specific protective proteins 3. Reduction of the immune response in some animals
RECOMBINANT SUBUNIT VACCINES Identify and isolate a specific gene from virulent bacteria or virus (gene that codes immuno protective protein). Gene is inserted into plasmid DNA and ligated with ligase. New (engineered) plasmid inserted into another bacterium (transform). Allowed to grow and actually produce the antigenic protein. The vaccine is comprised of purified proteins recovered from the expression vector. Hepatitis B Recombinant Vaccine (HBsAg) Target gene
RECOMBINANT SUBUNIT VACCINES Advantages: 1. No risk of pathogenicity 2. Defined composition 3. Simplified large scale production 4. Further engineering possible Disadvantages: 1. Multiple doses typically require 2. Adjuvants needed
4. Anti Idiotype Vaccines Ab Against Idiotype (Anti- Idiotype) Immunogen because of similarity of antigen and Ab against idiotype For dangerous Organisms HBV, rabies, Newcastle disease virus and FeLV, reoviruses and polioviruses
Anti idiotype Vaccines Virus antibody epitope Antibody with epitope binding site
Anti-Idiotype vaccine (cont) Antiidiotype antibody antibody Make antibody against antibody idiotype Anti-idiotype antibody mimics the epitope
Anti-idiotype antibody (cont 2) Use anti-idiotype antibody as injectable vaccine Anti-idiotype antibody Anti-anti-idiotype antibody Antibody to antiidiotype antibody Use as vaccine Anti-anti-idiotype antibody Binds and neutralizes virus Anti-anti-idiotype antibody
5. Synthetic peptide vaccines Synthesis of short chain peptide by immunogen epitopes(amino acid imminogen) with natural structure in lab which would be a great advantage for unstable viruses such as influenza
Synthetic peptide vaccines Advantages 1. Production and quality control simpler 2. No NA or other viral or external proteins 3. Production of humoral and cellular immunity without side effect Disadvantages 1. May be less immunogenic than conventional inactivated whole-virus vaccines 2. Requires adjuvant (Neutralization Ab) 3. Requires primary course of injections followed by boosters 4. Fails to elicit CMI 5. No total antigenic factors in synthetic peptide
New Lineage of Vaccines (Gen Vaccines) 1.DNA Vaccines 2. RNA Vaccines
Definition Insertion of the gene encoding the antigen into an bacterial plasmid(plasmid containing cloned DNA) Injection of the plasmid into the host The antigen is expressed and induces humeral and cellular immunity The antigenic protein(s) that are produced are processed in the same way as the proteins of the virus against which protection is to be produced.
Advantage of DNA Vaccine 1. Induction in cells and production of Immunogen protein & Ab like natural infectious (special & strong) 2. Encode multiple immunogenic epitopes 3. Safer than live virus vaccines 4. Cannot cause disease 5. No significant side effects (hundreds of patients; plasmid DNA vaccines) 6. Can not cause allergic and anaphilactice reactions by protein in booster injection 7. There is no protein component and so there will be no immune response against the vector itself 8. No infectious in immunodeficiency 9. Can generate both cell mediated and humoral immune responses 10. Treat and prevent
Advantage of DNA Vaccine (con.) 11. Injection of plasmid contains differnet antigenic genes (polyvalent) 12. There is a cell-mediated response that may be directed against any antigen in the pathogen 13. Protection against different lineages and against Antigenic Variation Factors 14. Mixtures of plasmids could be used that encode many protein fragments from a virus or viruses so that a broad spectrum vaccine could be produced 15. Can be combined with other vaccine approaches prime/boost approach 16. Longer shelf life (thermo stable) and long Immune memory in different temperatures and don t need to cold chain 17. Reduction of vaccine untill 100 to 1000 18. Easier and faster to manufacture (in comparison to recombinant) 19. Large Scale manufacturing procedures available
20. Commodious in comparison to recombinants 21. Allows a more simplified & effective quality control process 22. Faster design & development 23. A DNA sequence can be changed easily in the laboratory. This means that we can respond to changes in the infectious agent 24. This also offers protection against diseases caused by certain obligate intracellular pathogens (e.g. Mycobacterium tuberculosis) 25. No interfrance with maternal Ab 26. Don t need adjuvant 27. Similarity in production process of different genes vaccines
Possible Problems 1. Potential integration of plasmid into host genome leading to insertional mutagenesis 2. Induction of autoimmune responses (e.g. pathogenic anti-dna antibodies) 3. Induction of immunologic tolerance (e.g. where the expression of the antigen in the host may lead to specific non-responsiveness to that antigen)
Different types of Gen Vaccines In Designing & Researching: 1. Hepatitis C & G & E 2. Rabies 3. Papiloma Virus 4. Rotavirus 5. Mumps In Human clinical trial: 1. AIDS 2. Hepatitis B 3. Influenza 4. Cytomegalovirus
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