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Immunity and vaccine technology

Vaccines provide protective immunity and immunological memory to individuals, families and communities against any infectious disease.
Vaccines are cheap, cost – effective , easily administered and adaptable to mass vaccination.
Viral diseases can be managed through vaccination.

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Immunity and vaccine technology

  1. 1. Immunity and Vaccine Technology Presented by Dr. B. Victor., Ph.D. Email: bonfiliusvictor @ Blog:
  2. 2. Presentation outline  Introduction  Kinds of immunity-natural, acquired, active and passive immunity.  Immunization, vaccinationimportance.  Vaccines-prophylactic &therapeutic; monovalent & multivalent;  General classes of vaccines  Adjuvants  Vaccines of general use.  Problems in vaccine development.
  3. 3. Introduction “Disease prevention through immunization” Disease prevention is the key to public health. Vaccination stimulate immunity and immunologic memory similar to natural infection but without the risk of disease. Every year vaccine prevent up to 3 million deaths and save 750,000 children from disability.
  4. 4. Immunity = resistance = defense
  5. 5. Main Types of Immunity in Man
  6. 6. Kinds of immunity Natural or Innate or non-specific immunity Acquired or Adaptive or specific immunity  Prevents the entry of  Eliminates the antigens antigens into the body.  Antigen independent  No time lag  Not antigen specific  No Immunologic memory from the body.  Antigen dependent  A lag period  Antigen specific  Development of memory
  7. 7. Kinds of acquired immunity
  8. 8. Active immunity Active immunity refers to the process of exposing the body to an antigen to generate an adaptive immune response: The response takes days/weeks to develop but may be long lasting—even lifelong. Active immunity is usually classified as natural or acquired. Natural active immunity- The individual has developed immunity to a live pathogen by having been exposed to it. Acquired active immunity - by vaccination 
  9. 9. Passive immunity  Passive immunity refers to the process of providing IgG antibodies to protect against infection;  It gives immediate, but short-lived protection—several weeks to 3 or 4 months.  Passive immunity is usually classified as natural or acquired.  Natural passive immunity – refers to the transfer of maternal tetanus antibody (mainly IgG) across the placenta provides for the newborn baby.  Acquired passive immunity- refers to the process of obtaining serum from immune individuals.
  10. 10. Naturally acquired active immunity Artificially acquired active immunity  Naturally acquired active immunity – it occurs when the person is exposed to a live pathogen, develops the disease, and develops immunity.  Artificially acquired active immunity – It can be induced by a vaccine, a substance that contains the antigen.
  11. 11. Discovery of Vaccination  The word vaccine derived from the word vaca, meaning a cow in Spanish.   Edward Jenner discovered a vaccination for smallpox disease in 1796.  Jenner scratched some pus from a Cowpox sore into the arm of a boy James Phipps to see whether exposure to the virus protect the child from the smallpox virus.    Phipps was became immune, proving that inoculation with cowpox provided resistance against smallpox.
  12. 12. Louis Pasteur treated a boy against rabies by injecting spinal cord fluid of a rabid dog. The spinal cord fluid stimulated the production of antibodies against the rabies virus Louis Pasteur performed first experiment in immunology in July 6,1885.
  13. 13. Jenner introduced vaccination in 1796 using cowpox to protect against small pox. Golden age of vaccine technology – from 1950 – 1970. During this period, vaccines for polio, measles, mumps and rubella was developed.
  14. 14. What is vaccination?
  15. 15. Disease prevention by vaccination is of two types 1. Primary prevention – is an intervention before the biologic onset of disease e.g. prevention of infectious disease by vaccination. 2. Secondary prevention – is an intervention when disease can be detected at a stage before it is symptomatic e.g. AIDS.
  16. 16. Prophylactic and therapeutic vaccines Prophylactic vaccines – the vaccine is used to prevent the effects of a future infection by any natural or wild pathogen. e.g. anti-rabies vaccine. Therapeutic vaccines – the vaccines are devised to harness the immune response to treat diseases ranging from cancer to multiple sclerosis. E.g. cancer vaccine.
  17. 17. Monovalent and multivalent vaccines A monovalent (univalent) vaccine is designed to immunize against a single antigen or single pathogen. E.g. chicken pox. A multivalent (polyvalent) vaccine is designed to immunize against two or more strains of the same microorganism or against two or more microorganisms. E.g. DTP vaccine – (Diphtheriatetanus- pertusis vaccine). MMR vaccine – measles-mumps-rubella vaccine.
  18. 18. Importance of immunization  Vaccines provide protective immunity and immunological memory to individuals, families and communities against any infectious disease.  Vaccines are cheap, cost – effective , easily administered and adaptable to mass vaccination.  Vaccines are safe, thoroughly tested and monitored.  Vaccines stimulate both cell mediated and humoral immunities.  Viral diseases can be managed through vaccination.
  19. 19. Routes of vaccine administration Deep subcutaneous or intramuscular – most vaccines. Oral route – Sabine polio vaccine, oral BCG vaccine. Intra-dermal route – BCG vaccine. Scarification – small pox vaccine. Intranasal route – live attenuated influenza vaccine.
  20. 20. Kinds of vaccines
  21. 21. Broad categories of vaccines
  22. 22. 4-categories of traditional vaccines
  23. 23. Live attenuated vaccines -1 The live vaccine usually contains an attenuated non-pathogenic microorganism able to replicate in the host and produce long term protective immunity. Single dose is effective. No booster dose is required. Live microorganism tends to survive longer in the host and provide a wide range of immune responses.
  24. 24. Live attenuated vaccines -2 Merits Limitations  Relatively safe. Most  Severe reactions are viral vaccines belong to this group.  Offers long term protective immunity.  induces, both antibody as well as cell mediated immune responses.  Only single dose is required. possible.  Present the risk of contamination with unwanted organisms.  Present the risk of reverting back to virulence and cause disease.
  25. 25. Methods of attenuation The aim of attenuation is to eliminate the disease causing properties of the virus without affecting its immunity-inducing properties. 1. 2. 3. 4. 5. Viruses are given several consecutive passages in an unrelated host e.g. small pox virus in calf. Given multiple passages in cell cultures e.g rabies virus human cell cultures. Selecting less virulent strains e.g. cow pox virus for small pox. Long term treatment of viruses with chemicals e.g. BCG in a medium of bile. Culturing viruses under unfavorable conditions-temperature e.g. anthrax virus at40-50 0 C
  26. 26. Killed inactivated vaccines The inactivation process is aimed at destroying the pathogenicity of the microorganism while retaining its immunogenicity. Usually the pathogenic viruses are chemically inactivated. E.g. polio vaccine, rabies vaccine. Killed vaccines induce higher antibody titers but not effective as live vaccines. Killed vaccines are safe with respect to residual virulence. Since antibody titers diminish with time, repeated vaccinations are required.
  27. 27. Toxoids  The toxins of microorganisms are treated with formalin and incubated at 37 0C for 3- 4 weeks.  The denatured toxin is called a ‘toxoid’.  Toxoids often induce low levels of immune response and are often administered with an adjuvant.  Toxoid vaccines often require a booster every ten years.  Toxoids e.g. the diphtheria and tetanus vaccines are usually combined with pertussis vaccine as DPT immunization.  When more than one vaccine is administered together it is called ‘conjugated vaccine.
  28. 28. Subunit vaccines Biotechnology and genetic engineering techniques have been used to produce "subunit vaccines" To create a subunit vaccine, researchers isolate the genes which code for appropriate subunits from the genome of the infectious agent. This genetic material is placed into bacteria or yeast host cells which then produce large quantities of subunit molecules by transcribing and translating the inserted foreign DNA. These subunit molecules are isolated, purified and used as a vaccine.  e.g. Hepatitis B vaccine
  29. 29. DNA Vaccines  With DNA vaccines, the individual is not injected with the antigen but with DNA encoding the antigen.  The DNA is incorporated in a plasmid containing DNA sequences encoding one or more protein antigens.  DNA sequences are incorporated with a promoter that will enable the DNA to be efficiently transcribed in the human cells.  The DNA vaccine can then be injected into a muscle just as conventional vaccines.  DNA vaccines elicit cell-mediated and antibodymediated immune responses.  DNA vaccines has been developed against tuberculosis, SARS, smallpox, and other intracellular pathogens.
  30. 30. Properties of an ideal vaccine 1. Should provide long lasting immunity. 2. Should induce both humoral and cell mediated immunity. 3. Should not induce autoimmunity or hypersensitivity reactions. 4. Should be inexpensive to produce, easy to store and administer. 5. Should be safe and effective.
  31. 31. Adjuvants  The word adjuvant is derived from the Latin word ‘adjuvare’ meaning ‘to help’. Certain substances, when administered simultaneously with a specific antigen, will enhance the immune response to that antigen. Such compounds are routinely included in inactivated or purified antigen vaccines.
  32. 32. Adjuvants in common use: 1. Aluminium salts First safe and effective compound to be used in human vaccines. It promotes a good antibody response, but poor cell mediated immunity. 2. Liposomes and Immunostimulating complexes (ISCOMS) 3. Complete Freunds adjuvant is an emulsion of Mycobacteria, oil and water 4. Incomplete Freund's adjuvant as above, but without Mycobacteria. 5. Muramyl di-peptide Derived from Mycobacterial cell wall. 6. Cytokines IL-2, IL-12 and Interferon-gamma.
  33. 33. Mode of action of adjuvants By trapping antigen in the tissues,  thus allowing maximal exposure to dendritic cells and specific T and B lymphocytes. By activating antigen-presenting cells to secrete cytokines that enhance the recruitment of antigen-specific T and B cells to the site of inoculation.
  34. 34. Vaccines in general use:
  35. 35. Measles vaccine Two types of vaccines are available for measles. Mumps Measles Rubella vaccine, live (MMR-II) Mumps Measles Rubella and varicella virus vaccine (Proquad) MMR vaccine is a live attenuated viral vaccine used to induce immunity against measles, mumps and rubella. The vaccine is administered to all children in the second year of life.
  36. 36. Mumps vaccine A killed mumps  virus vaccine developed in 1948 and used in the United States from 19501978.  Live attenuated virus developed in the 1960's.   MMR vaccine is an immunization vaccine against measles, mumps and rubella(also called German measles). All three diseases are highly contagious. MMR is a mixture of live  attenuated viruses  of the three diseases. The MMR vaccine is administered to children by a subcutaneous injection.
  37. 37. Rubella vaccine Live attenuated virus. Rubella causes a mild febrile illness in children, but if infection occurs during pregnancy, the foetus may develop severe congenital abnormalities. In the USA, the vaccine is administered to all children in their second year of life .
  38. 38. Polio vaccine  Two polio vaccines are used to fight the disease poliomyelitis.  Inactivated polio virus vaccine (IPV) consists of inactivated (dead) polio virus. It was developed by Jonas Salk in 1952.  Oral polio vaccine (OPV) is a live attenuated polio virus. This vaccine was developed by Albert Sabin in 1957.  OPV is adopted in most parts of the world.  The live viral vaccine induce life long immunity.  OPV is sensitive to storage under adverse conditions.
  39. 39. Hepatitis B vaccine Two immunization vaccines are available for use: a serum derived vaccine and a recombinant vaccine. Both contain purified preparations of the hepatitis B surface protein. The serum derived vaccine is prepared from hepatitis B surface protein, purified from the serum of hepatitis B carriers. A second vaccine is produced by recombinant DNA technology.  Three doses are given to children at 6, 10, and 14 weeks of age.
  40. 40. Hepatitis A vaccine, HAV HAV has been developed from formalin- inactivated , Human fibroblast cell culture-derived virus. Hepatitis A is a serious liver disease caused by the hepatitis A virus (HAV). A combination vaccine containing inactivated hepatitis A and recombinant hepatitis B vaccines has been licensed since 1996 for use in children aged one year or older in several countries. The combination vaccine is given as a three-dose series, using a 0, 1, 6 month schedule.
  41. 41. Yellow Fever vaccine  The vaccine consists of a live attenuated, strain of the yellow fever virus called 17D.  Max Theiler developed the yellow fever vaccine in 1937. A single dose induces protective immunity to travellers and booster doses, every 10 years, are recommended for residents in endemic areas.
  42. 42. Rabies vaccine  Rabies is an acute, progressive encephalomyelitis caused by neurotropic viruses in the family Rhabdoviridae.   The human diploid cell rabies vaccine (H.D.C.V.) was started in 1967. Human diploid cell rabies vaccines are  made using the attenuated Pitman-Moore L503 strain of the virus.  Recombinant rabies vaccine (V-RG) was developed in 1984 by inserting the glycoprotein  gene from rabies into a vaccinia virus.
  43. 43. Influenza vaccine  The flu is a respiratory disease that is caused by an influenza virus.  Influenza Virus Vaccine is an inactivated influenza virus propagated in embryonated chicken eggs.  It is an intramuscular injectable vaccine available in two forms:  The trivalent vaccine, which protects against three flu virus strains  The quadrivalent vaccine, which protects against four flu virus strains
  44. 44. Varicella- Zoster virus vaccine The vaccine is developed from a live attenuated strain of varicella zoster virus. It is used to protect individuals from chickenpox. This vaccine is a shot given subcutaneously (under the skin).  It is recommended for all children under 13 or older who has never had chickenpox. Two doses are administered 4 to 8 weeks apart.[
  45. 45. Live vector vaccines A live vector vaccine is a vaccine that uses a chemically weakened virus to transport pieces of the virus in order to induce an immune response. Viral vector vaccines are developed for major infectious diseases like HIV, tuberculosis and malaria. Vector vaccines are developed using recombinant DNA technology. Viral vectors elicit a strong humoral and cell mediated responses and cause immunological memory.
  46. 46. Cancer vaccines  Cancer vaccines can be used as an active immunotherapy and trigger the immune system to attack cancer cells with one or more specific antigens.  Cancer vaccines are developed from proteins or peptide antigens rather than whole tumor cells.  Two kinds of tumor cell vaccines : Autologous and allogenic vaccines.  Autologous vaccine means ‘coming from the self’ = killed tumor cells taken from the same person.  Allogenic vaccine means ‘coming from another’ =mix of cells removed from several patients.
  47. 47. Problems in vaccine development  Many kinds of viruses may cause similar diseases. e.g. common cold. A single vaccine may not prevent such diseases.  Diseases caused by RNA viruses may not be controlled because of antigenic drift and shift.  Diseases present in large animal reservoirs may reinfect after elimination from the human population.  Integration of viral DNA into host chromosomes may cause problems.  There is possibility of recombination and mutation of attenuated viruses in vaccines.
  48. 48. Summary Vaccines provide protective immunity and immunological memory to individuals, families and communities against any infectious disease. Vaccines are cheap, cost – effective , easily administered and adaptable to mass vaccination. Viral diseases can be managed through vaccination.
  49. 49. About the presenter  Dr. B. Victor is a highly experienced postgraduate professor, retired from the reputed educational institution - St. Xavier’ s College(Autonomous), Palayamkottai, India-627001.  He was the dean of sciences, assistant controller of examinations and coordinator several academic research workshops.  He has more than 32 years of teaching and research experience  He has taught a diversity of courses and published 45 research articles in reputed national and international journals.  Send your comments to :