1. Applied Immunology
Lecture notes
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
The specificity of the bond between antibody and antigen has made it an excellent tool in the detection of substances in a variety of diagnostic techniques. Antibodies specific for a desired antigen can be conjugated with a radiolabel, fluorescent label, or color-forming enzyme and are used as a "probe" to detect it. However, the similarity between some antigens can lead to false positives and other errors in such tests by antibodies cross-reacting with antigens that aren't exact matches

4. The immune system is the ministry of defence of the human/animal body
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
Cells
Immunoglobulins

8. Overview of the immune system
Innate (nonspecific)
1st line of defense
Cellular components
Humoral components
Adaptive
(specific)
2nd line of defense

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)
Anomy and forgion

10. Antigen and antibody

11. IgM (first exposure, large, not passing placenta, huge amont)
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)
IgG is the most abundant immunoglobulin and is approximately equally distributed in blood and in tissue liquids, comprising 75% of serum immunoglobulins in humans, IgG molecules are synthesized and secreted by plasma B cells.
Immunoglobulin A (IgA) is an antibody that plays a critical role in mucosal immunity. More IgA is produced in mucosal linings than all other types of antibody combined
In biology, Immunoglobulin E (IgE) is a class of antibody (or immunoglobulin "isotype") that has only been found in mammals. IgE is a monomeric antibody with 4 Ig-like domains (CH1->CH4). [1] It plays an important role in allergy, and is especially associated with type 1 hypersensitivity.[2] IgE has also been implicated in immune system responses to most parasitic worms
Immunoglobulin D (IgD) is an antibody isotype that makes up about 1% of proteins in the plasma membranes of mature B-lymphocytes where it is usually coexpressed with another cell surface antibody called IgM. IgD is also produced in a secreted form that is found in very small amounts in blood serum.

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,
Primary antibodies are antibodies raised against an antigenic target of interest (a protein, peptide, carbohydrate, or other small molecule) and are typically unconjugated (unlabelled).
secondary antibody is an 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 Study Guide
Why do soluble antigens and antibodies precipitate?
Antigen
Antibody

17. Agglutination RBC RBC RBC IgM Antibody RBC RBC RBC RBC RBC
Study Guide
What is the difference between precipitation and agglutination?
IgG Antibody
RBC
RBC
RBC

18. Factors influencing immunogenicity
Contribution of immunogen
Contribution of biological system
Method of administration

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
Study Guide
What is the significance of class switching?
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. Kinetics of the Ab Response T-dependent Ag; 1o Response
D a y s A f t e r I m m u n i z a t i o n
A b T i t e r
LAG
LOG
DECLINE
PLATEAU
Lag
Log
Plateau
Decline

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

25. 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
Illustration of the famous first vaccination experiment. In 1796 Edward Jenner infected eight-year-old James Phipps with fluid from a lesion on the hand of Sarah Nelmes, who had caught cowpox. The word ‘vaccination’ comes from the Latin word ‘vaccinia’ for cowpox. This was a successful experiment, because the boy was subsequently protected against a human smallpox infection. Years later Louis Pasteur proposed that all inoculations intended to protect against infectious diseases should be called vaccinations, in honour of Jenner.

27. Variolation
The word ‘variolation’ comes from the Latin word ‘variola’ for human smallpox.
Figure 1. Ancient Oriental print illustrating the technique of variolation. Dried material from scabs of human smallpox is blown into the nose of an unaffected person with a small blowpipe. The word ‘variolation’ comes from the Latin word ‘variola’ for human smallpox.

28. Discovery of small pox vaccine
In 1798, Jenner introduced 1st vaccination (vacca: cow) following his experimentation with isolates of cow pox virus from ‘Blossom’.
Cartoon on smallpox vaccination from 1802 entitled “The Cow Pock or the Wonderful Effects of the New Inoculation”. It shows Edward Jenner and persons who are developing cow-like projections as a result of allowing themselves to be inoculated with an ‘animal disease
Edward Jenner 1780AD
Blossom 28

30. Types of acquired immunity

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

32. Mode of delivery

33. 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

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

35. Serological tests based on Abs specifically binding to Ag
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.

36. Enzyme (ELISA) Immunoassay
Enzyme conjugated to anti-Ig antibody (“second antibody”)
Add
substrate
for enzyme
anti-antigen
antibody
Study Guide
Radioimmunoassays (RIA) and Immunfluorescence Assays (IFA) depend on the detection of a radionuclide or a fluorescent probe attached to the second antibody, instead of the enzyme. In those cases, no substrate is needed.
How would you use this assay to measure the concentration or detect the presence of an antigen?
Antigen

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

38. 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.

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

40. agglutination is the clumping of particles
agglutination is the clumping of particles. The word agglutination comes from the Latin agglutinare, meaning "to glue to."
This occurs in biology in three main examples:
The clumping of cells such as bacteria or red blood cells in the presence of an antibody. The antibody or other molecule binds multiple particles and joins them, creating a large complex.
The coalescing of small particles that are suspended in a solution; these larger masses are then (usually) precipitated.
An allergic reaction type occurrence where cells become more compacted together to prevent foreign materials entering them. This is usually the result of an antigen in the vicinity of the cells.

41. Acute infection Onset of symptoms Incubation Primary infection Days
Modified from Hedman et al. 2000
Primary infection
Days
Weeks
Months
Years

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

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

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

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

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

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

48. 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