Active and passive immunity

Active and passive immunity

1. Active and passive immunity Rizwan Abbas Baho

2. The Nature of Disease Pathogenic Organisms Genetic Disorders Toxic Chemicals Other Environmental Factors Physical Damage to Organs Nutritional Disorders

3. Types of Pathogenic Organisms Viruses Bacteria Protozoan Fungi Animal Parasites

4. Mechanisms of Disease by Pathogens Utilization of host nutritional resources Physical damage to host tissues Production of toxic substances Chromosomal and gene damage Body cells behave abnormally

5. Defense Mechanisms External Defense Internal Defense Immune Defense

6. Skin acts as barrier to microbes and viruses - sweat has a low pH Mucus traps foreign particles Tears - Lysozyme has antimicrobial action Gastric stomach acid 1 st Line of Defense

7. Body Coverings: The Skin sebaceous glands sweat gland epidermis

8. Body Coverings: Mucous Membranes mucus cilia

9. Phagocytic cells (WBCs ) Natural Killer (NK) Cells: attack virus infected cells Inflammatory Response Antimicrobial proteins Lysozyme Interferon Antibodies 2 nd Line of Defense

10. Nonspecific Phagocytosis Neutrophils Monocytes Eosinophils

11. Mechanism of Phagocytosis Macrophage

12. Inflammatory Response Histamine & prostaglandins released Capillaries dilate Clotting begins Chemotactic factors attract phagocytic cells Phagocytes consume pathogens & cell debris

13. Lymphatic System 3 rd Line of Defense

14. Immunity: The state of being immune from or insusceptible to a particular disease. The condition that permits either natural or acquired resistance to disease . The ability of the cell to react immunologically in the presence of antigen.

15. How immunity develops During the body’s first encounter with a pathogen there will be few lymphocytes with specific receptors It takes time to divide to form clones, B lymphocytes to secrete antibodies, T lymphocyte production If the same pathogen invades again persisting memory cells can give a faster, more effective response

16. Characteristics of Immunity Recognition of self versus non-self Response is specific Retains a “memory” allowing an accelerated second response Can respond to many different materials Involves lymphocytes and antibodies

17. Types of Immunity Active Immunity Naturally-Acquired Active Immunity Artificially-Acquired Active Immunity Passive Immunity Naturally-Acquired Passive Immunity Artificially-Acquired Passive Immunity

18. Types of Immunity

19. An infection is an example of acquiring natural immunity. It is called ACTIVE as your body needs to work to produce the necessary antibodies When a mother breast feeds her baby she passes antibodies to it. This is a way of acquiring PASSIVE immunity as it is a way of gaining antibodies without the immune system having to produce them. The thick, yellowish milk (colostrum) that is produced for the first few days after birth is particularly rich in antibodies. Natural immunity: active and passive

20. Artificial immunity: active and passive An alternative to natural immunity developing is to give vaccinations (artificial immunity) Antigen is injected into the body . This may be in the form of an inactivated bacterial toxin or attenuated (not harmful) virus which would promote ACTIVE immunity; or the injection of antibodies or antitoxins which would promote PASSIVE immunity ( eg Clostridium tetani )

21. The production of antibodies against a specific disease by the immune system. Naturally acquired through disease Artificially acquired through vaccination Vaccines include inactivated toxins, killed microbes, parts of microbes, and viable but weakened microbes. Memory cells are only produced in active immunity. Protection for active immunity is permanent whereas in passive immunity it is only temporary. Antigens are only encountered in active immunity. Active immunity takes several weeks to become active but passive is immediate Active Immunity

22. A vaccinated person has a secondary response based on memory cells when encountering the specific pathogen. Routine immunization against infectious diseases such as measles and whooping cough, and has led to the eradication of smallpox, a viral disease. Unfortunately, not all infectious agents are easily managed by vaccination. HIV vaccine in the works

23. Passive Immunity- Protection against disease through antibodies produced by another human being or animal . Ex . Maternal antibodies , Colostrum Passive immunity doesn’t last as long as active immunity (only weeks or months): No lymphocytes are stimulated to clone themselves No memory cells have been made Effective, but temporary as t his type of immunity can only last as long as the antibodies/toxins last in the blood Passive Immunity

24. Passive immunity can be transferred artificially by injecting antibodies from an animal that is already immune to a disease into another animal. Rabies treatment: injection with antibodies against rabies virus that are both passive immunizations (the immediate fight) and active immunizations (longer term defense).

25. Immune System Response to Antigens A. Humoral Immunity Involves antibodies (secreted from B cells) dissolved in the blood plasma. Demonstrated as a immune response using only the blood serum. Defense against bacteria, bacterial toxins, & viruses . B. Cell-Mediated Immunity Involves the activities of specific white blood cells (T cells). Defense against cancer cells, virus-infected cells, fungi, animal parasites, & foreign cells from transplants.

26. Lymphocyte Formation

27. B Cells Mature in bone marrow Involved in humoral immunity Once activated by antigen, proliferate into two types of clones P lasma cells that secrete antibodies and memory cells that may be converted into plasma cells at a later time

28. B Cells antibodies

29. Activation of B Cells by Antigen antigen

30. Clonal Selection

31. Clonal Selection plasma cells memory cells antibodies

32. T Cells Mature in thymus Involved in cell-mediated immunity Activated when another cell presents antigen to them Several types of T cells: cytoxic T cells, helper T cells, suppressor T cells, memory T cells

33. There are two main types of T cells, and each responds to one class of MHC molecule. Cytotoxic T cells ( T C ) have antigen receptors that bind to protein fragments displayed by the body’s class I MHC molecules. Helper T cells (T H ) have receptors that bind to peptides displayed by the body’s class II MHC molecules. T Cells

34. Cytotoxic T Cell perforin pores in target cell

35. Helper T Cells interleukin 1 macrophage helper T cell bacterium bacterial antigens T cell receptor

36. Humoral Immune Response time (days) antibody concentration first exposure to antigen A

37. Humoral Immune Response time (days) antibody concentration first exposure to antigen A primary response: concentration of anti-A antibody second exposure to antigen A

38. Humoral Immune Response time (days) antibody concentration secondary response: concentration of anti-A antibody second exposure to antigen A first exposure to antigen B

39. Humoral Immune Response time (days) antibody concentration primary response: concentration of anti-B antibody first exposure to antigen B

40. Antibodies constitute a group of globular serum proteins called immunoglobins ( Igs ). A typical antibody molecule has two identical antigen-binding sites specific for the epitope that provokes its production. Antibody Molecule antigen binding sites antigen light chains heavy chains

41. Mechanisms on Antibody Action Precipitation of soluble antigens Agglutination of foreign cells Neutralization Enhanced phagocytosis Complement activation leading to cell lysis Stimulates inflammation The binding of antibodies to antigens to form antigen-antibody complexes is the basis of several antigen disposal mechanisms

42. The classical complimentary pathway, resulting in lysis of a target cell

43. Overview of Immune System Responses

44. Malfunctions of the immune system can produce effects ranging from the minor inconvenience of some allergies to the serious and often fatal consequences of certain autoimmune and immunodeficiency diseases. Abnormal immune function can lead to disease Abnormal Immune Function Autoimmune Disease Allergy Immunodeficiency

45. vaccines Types of vaccines

46. Vaccination Vaccination is a method of giving antigen to stimulate the immune response through active immunization. A vaccine is an immuno-biological substance designed to produce specific protection against a given disease. A vaccine is “antigenic” but not “pathogenic”. One of the most effective « weapons » in medicine 1798 Edward Jenner immunizes first time against smallpox 1 885 Louis Pasteur prepares the 1st vaccine against Rabbies 1927 BCG (bacillus Galmette -Guerin ) 1955 Salk vaccine against poliomyelitis 1960 MMR (Measles, Mumps and Rubella ) … …..

47. Types of vaccines Live vaccines Attenuated live vaccines Inactivated (killed vaccines) Toxoids Polysaccharide and polypeptide (cellular fraction) vaccines Surface antigen (recombinant) vaccines

48. Live vaccines Live vaccines are made from live infectious agents without any amendment. The only live vaccine is “ Variola ” small pox vaccine , made of live vaccinia cow-pox virus (not variola virus) which is not pathogenic but antigenic, giving cross immunity for variola .

49. Live attenuated ( avirulent ) vaccines Virulent pathogenic organisms are treated to become attenuated and avirulent but antigenic. They have lost their capacity to induce full-blown disease but retain their immunogenicity. Attenuated – live microbe (usually virus) which has a vital function inactivated by heat, chemicals or genetic manipulation e.g. Rabies virus vaccine, MMR (Measles, Mumps and Rubella), BCG (Bacillus Calmette Guerin vaccine for M. tuberculosis Risk it could revert back to infectious agent will stimulate both cell mediated and antibody mediated immune response

50. Live attenuated ( avirulent ) vaccines contd.. Live attenuated vaccines should not be administered to persons with suppressed immune response due to: Leukemia and lymphoma Other malignancies Receiving corticosteroids and anti-metabolic agents Radiation pregnancy

51. Inactivated (killed) vaccines Organisms are killed or inactivated by heat or chemicals but remain antigenic. They are usually safe but less effective than live attenuated vaccines. The only absolute contraindication to their administration is a severe local or general reaction to a previous dose

52. Toxoids They are prepared by detoxifying the exotoxins of some bacteria rendering them antigenic but not pathogenic. Adjuvant (e.g. alum precipitation) is used to increase the potency of vaccine. The antibodies produces in the body as a consequence of toxoid administration neutralize the toxic moiety produced during infection rather than act upon the organism itself. In general toxoids are highly efficacious and safe immunizing agents.

53. Polysaccharide and polypeptide vaccines They are prepared from extracted cellular fractions e.g. meningococcal vaccine from the polysaccharide antigen of the cell wall, the pneumococcal vaccine from the polysaccharide contained in the capsule of the organism, and hepatitis B polypeptide vaccine . Their efficacy and safety appear to be high.

54. Surface antigen (recombinant) vaccines It is prepared by cloning HBsAg gene in yeast cells where it is expressed. HBsAg produced is then used for vaccine preparations. Their efficacy and safety also appear to be high.

55. TYPES OF VACCINES Live vaccines Live Attenuated vaccines Killed Inactivated vaccines Toxoids Cellular fraction vaccines Recombinant vaccines Small pox variola vaccine BCG Typhoid oral Plague Oral polio Yellow fever Measles Mumps Rubella Intranasal Influenza Typhus Typhoid Cholera Pertussis Plague Rabies Salk polio Intra-muscular influenza Japanise encephalitis Diphtheria Tetanus Meningococcal polysaccharide vaccine Pneumococcal polysaccharide vaccine Hepatitis B polypeptide vaccine Hepatitis B vaccine

56. Routes of administration Deep subcutaneous or intramuscular route (most vaccines) Oral route ( oral BCG vaccine) Intradermal route (BCG vaccine) Scarification (small pox vaccine) Intranasal route (live attenuated influenza vaccine)

57. Scheme of immunization Primary vaccination One dose vaccines (BCG, variola , measles, mumps, rubella, yellow fever) Multiple dose vaccines (polio, DPT (diphtheria , pertussis, tetanus toxoids ), hepatitis B) Booster vaccination To maintain immunity level after it declines after some time has elapsed (DT, MMR).

58. Periods of maintained immunity by vaccines Short period (months): cholera vaccine Two years: TAB vaccine Three to five years: DPT vaccine Five or more years: BCG vaccine Ten years: Yellow fever vaccine Solid immunity: MMR (measles, mumps, and rubella vaccines)

59. Levels of effectiveness Absolutely protective(100%): yellow fever vaccine Almost absolutely protective (99%): Variola , measles, mumps, rubella vaccines, and diphtheria and tetanus toxoids. Highly protective (80-95%): polio, BCG, Hepatitis B, and pertussis vaccines. Moderately protective (40-60%) TAB, cholera vaccine, and influenza killed vaccine.

60. The Cold Chain The "cold chain" is a system of storage and transport of vaccines at low temperature from the manufacturer to the actual vaccination site. The cold chain system is necessary because vaccine failure may occur due to failure to store and transport under strict temperature controls.

61. The Cold Chain Equipment Cold chain equipment consists of the following: (a) Walk in cold rooms: They are located at regional level, meant to store vaccines up to 3 months and serve districts. (b) Deep freezers (300 ltr ) and Ice lined Refrigerators: supplied to all districts and the WIC locations to store vaccines. Deep freezers are used for making ice packs and to store OPV and measles vaccines. (c) Small deep freezers and ILR (140 ltr ) : One set is provided to PHCs, and Family Planning Centers

62. (d) Cold boxes : Cold boxes are supplied to all peripheral centers. These are used mainly for transportation of the vaccines. (e) Vaccine carriers: Vaccine carriers are used to carry small quantities of vaccines (16-20 vials) for the out of reach sessions. 4 fully frozen ice packs are used for lining the sides, and vials of DPT, DT, TT and diluents should not be placed in direct contact with frozen ice packs. The carriers should be closed tightly. (f) Ice packs: The ice packs contain water and no salt should be added to it.

63. Among the vaccines, P olio vaccine is the most sensitive to heat, requiring storage at minus 20 degree C. Vaccines which must be stored in the FREEZER COMPARTMENT are : polio and measles. Vaccines which must be stored in the COLD PART but never allowed to freeze are : typhoid, DPT, tetanus toxoid, DT, BCG and diluents

64. Vaccination Coverage Vaccination coverage is the percent of at risk or susceptible individuals, or population who have been fully immunized against particular diseases by vaccines or toxoids. To be significantly effective in prevention of disease on mass or community level at least a satisfactory proportion (75% or more) of the at risk population must be immunized.

65. Herd immunity : At least 80-85% of the population need to be vaccinated to reduce the chance of somebody catching the disease – even some one who has not been vaccinated- to safe levels.

66. Ways of achieving satisfactory immunization coverage Efficient immunization service; urban and rural Health awareness and cooperation of the public Periodic mass immunization campaigns, to cover those who missed regular immunizations Outreach programs in rural and nomad areas, and home visits

67. Application of active immunization Infants and children expanded immunization program (schedule) Active immunization for adult females Vaccination for special occupations Vaccination for special life styles Vaccination for special environmental situations Vaccinations for special health status persons Vaccinations in travel Vaccines against bioterrorism