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Applied Immunology

Applied Immunology. Aftab Jasir: European Centre for Disease Prevention and Control (ECDC) European Public Health Microbiology training program (EUPHEM) Introductory course, Menorca,2012. Objectives. Define basic components of immunology Describe important terms in immunology

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Applied Immunology

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  1. Applied Immunology Aftab Jasir: European Centre for Disease Prevention and Control (ECDC) European Public Health Microbiology training program (EUPHEM) Introductory course, Menorca,2012

  2. Objectives • Define basic components of immunology • Describe important terms in immunology • Explain major applications of immunology

  3. What is immunology? • Immunology is a broad branch of biomedical science that covers the study of all aspects of the immune system in all living organisms. • It deals with the physiological functioning of the immune system in states of both health and disease

  4. What is the immune system? The immune system is the ministry of defence of the human/animal body

  5. Immunologically Naive No previous experience No memory Must be educated

  6. Immunodeficiency and Immunosuppression Immunodeficiencyis a state in which the immune system's ability to fight infectious disease is low or entirely absent. Immunosuppression involves an act that reduces the activation or efficacy of the immune system. immunosuppression may occur as an adverse reaction to treatment of other conditions.

  7. Major defence components of the human immune system Immunoglobulins Cells

  8. Overview of the immune system

  9. Definitions/terminology Antigens (Ag) Large molecules, is anything that obtain the formation of a specific immune response (Anomy) Ag determinants (epitopes) are the particular chemical groups on a molecule that are antigenic Antibody(Ab)/immunoglobulin (Ig). A special group of soluble proteins that are produced in response to foreign antigens (substances)

  10. Antigen and antibody

  11. 5 classes of IGs IgM (first exposure, large, not passing placenta, huge amont) IgG (secondary exposure, small, passing placenta) IgD (proteins in the plasma membranes of mature B-lymphocytes, same time as IgM) IgA (mucosal immunity, respiratory tract) IgE (Allergy and parasites)

  12. Haptens Vaccine conjugate

  13. Ministry of defence of the human body

  14. Antibody Protection of the Host

  15. Primary and secondary antibodies P: antibodies raised against an antigenic target of interest and are typically unconjugated. S: antibody that binds to primary antibodies or antibody fragments. They are typically labeled with probes that make them useful for detection,

  16. Immune Precipitation Antigen Antibody

  17. RBC RBC RBC RBC RBC RBC RBC RBC RBC RBC RBC Agglutination IgM Antibody IgG Antibody

  18. Factors influencing immunogenicity

  19. Class Switching Biological mechanism that changes a B cell's production of antibody from one class to another, for example, from IgM to IgG. antibody titer IgM IgG time

  20. Four phases of the primary response • lag phase where no antibody is detected • log phase in which the antibody titer rises logarithmically • plateau phase during which the antibody titer stabilizes • phase (decline) during which the antibody is cleared or catabilized

  21. LOG PLATEAU DECLINE LAG A b T i t e r Ag D a y s A f t e r I m m u n i z a t i o n Kinetics of the Ab ResponseT-dependent Ag; 1o Response • Lag • Log • Plateau • Decline

  22. 2o Ag 1o Ag A b T i t e r D a y s A f t e r I m m u n i z a t i o n Kinetics of the Ab ResponseT-dependent Ag; 2o Response • Lag • Log • Plateau • Decline

  23. Major practical applications of immunology • Use of antiserum and vaccination to provide protection against disease. • Diagnostic tool to detect disease. • Epidemiological investigation of vaccine preventable diseases

  24. My face is my fortune Where are you going, my pretty maid?I’m going a-milking, sir, she said May I go with you, my pretty maid?You’re kindly welcome, sir, she said What is your father, my pretty maid?My father is a farmer, sir, she said What is your fortune, my pretty maid?My face is my fortune, sir, she said

  25. Variolation The word ‘variolation’ comes from the Latin word ‘variola’ for human smallpox.

  26. Discovery of small pox vaccine Blossom Edward Jenner 1780AD

  27. Types of acquired immunity

  28. Passive – receive Abs made by another 1. natural 2. artificial - γ globulin, hyperimmune serum Artificial Natural

  29. Mode of delivery

  30. Disadvantages Advantages Advantages and Disadvantages of Active Immunization Not immediate Immune suppressed/deficiency Long term immunity Herd immunity Risk of infection Risk of contamination Animal ??? Attenuated can revert to their pathogenic form

  31. Disadvantages Advantages Advantages and Disadvantages of Passive Immunization no long term protection serum sickness immediate protection risk of hepatitis and HIV graft vs. host disease

  32. Serology • A science that attempts to detect signs of infection in a patient’s serum such as Ab for a specific microbe • Serological tests based on Abs specifically binding to Ag • Ag of known identity will react with Ab in an unknown serum sample. • Known Ab can be used to detect Ag in serum • Ag-Ab reactions are visible by clumps, precipitates, color changes or release of radioactivity. • The most effective tests have high specificity and sensitivity.

  33. Enzyme (ELISA) Immunoassay Enzyme conjugated to anti-Ig antibody (“second antibody”) Add substrate for enzyme anti-antigen antibody Antigen

  34. a) The presence of a specific Ab b) Identification of microbes

  35. Specificity, sensitivity, and cross reactivity • a) Specificity • Ab attaches with great exact-ness to only one type of Ag. • b) Sensitivity • Ab can locate Ag, even when it is greatly diluted. • c) Cross reactivity • the ability of an individual antibody combining site to react with more than one antigenic determinant or the ability of a population of antibody molecules to react with more than one antigen.

  36. Examples of serological tests Agglutination tests Precipitation tests Immunoelectrophoresis Western blot tests Complement fixation tests Immunofluorescence testing Immunoassays

  37. Acute infection Onset of symptoms Incubation Primary infection Days Weeks Months Years

  38. Acute infection Onset of symptoms IgM Incubation Primary infection Days Weeks Months Years

  39. Acute virus infection Onset of symptoms IgG IgM Incubation Primary infection Days Weeks Months Years

  40. Avidity = the sum of affinities between: antibody and antigen Acute virus infection Onset of symptoms IgG avidity IgG IgM Incubation Primary infection Days Weeks Months Years

  41. Onset of symptoms IgG avidity IgG IgM Incubation Persistence Primary infection Secondary infection or reactivation Days Weeks Months Years

  42. Onset of symptoms IgG avidity IgG IgM Viremia Primary infection Secondary infection or reactivation Days Weeks Months Years

  43. Q fever IgM2 IgM1 IgG2 1/800 IgG1 IG titter 1/64 1/40 1 1 2 1 2 Time

  44. What should you have in mind!!! Tack home massage • Some times Ag x Ab based tests can results in wrong alarm of outbreak ( Salmonella) • Antigen variation is always a problem (Chlamydia, grouping of streptococci) • Cross-reactivity can give wrong information of an outbreak • Any unusual or unexpected results should be confirmed by genetic test • If possible use other methods than serology in an outbreak situation or combine with other methods

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