1. The Adaptive Immune Response “Match me perfectly and I’m neutralized”
Kathy Huschle
Northland Community and Technical College

2. Adaptive Immune Response
in contrast to the innate immune response which we are basically born with, the adaptive immune response is an ever developing system
it continues to mature throughout our life

3. Adaptive Immune Response
in most cases as each new microbial invader is encountered, our adaptive immune response initiates a specific attack against the invader
generally this invader is remembered and that “memory” is readily available in the case of a second or subsequent attack from the same invader

4. Adaptive Immune Response
this system is an extremely complex system to which we will attempt to gain a basic understand
immunologists are continually discovering many facts about the adaptive immune response

5. Adaptive Immune Response
the adaptive immune response
is learned or acquired
recognizes specific substances foreign to the body
is essential for life

6. Adaptive Immune Response
other terms used for the adaptive immune response include
acquired immunity
specific immunity
though at one time thought to function exclusive of the innate immune system, research is now discovering a correlation between the two systems
regardless of a correlation or not, the failure of our immune system results in mortality

7. Adaptive Immune Response
adaptive immune response is characterized by
specificity
memory
learned ability to recognize (acquired) pathogens which allows the body to usually only suffer once from that particular pathogen

8. Components of the Adaptive Immune System
antigens
antibodies
lymph system
lymphocytes
B cells
T cells
NK cell (Natural Killer)
Antigen
Antibody
B cell
T cell
NK cell

9. Antigens
the term antigen derives from the two words antibody generator
most antigens are proteins or large polysaccharides

10. Antigens
often a component of invading microbes, such as the capsule, cell wall, flagella, toxin
particular chemical that will activate the adaptive immune response
Antigens found in autologous tumor

11. Antigens invading microbes can have many antigens on its surface
pathogen

12. Antigens two essential properties of antigens include immunogenicity
the ability to stimulate immune system
antigen-antibody complex

13. Antigens specific reactivity
the ability to react with effector molecules (antibody) to form an antigen-antibody complex
Antigens in red with green borders

14. Antibodies glycoproteins that are also referred to as immunoglobiulins
basic structure is a Y shaped molecule with 2 functional parts
Fab region
Fc region
Fab region
Fc region

15. Antibodies
Fab region
this is the part of the antibody that binds to the antigen
Fc region
the stem of the antibody that functions as a “red flag”
notifies the rest of the immune system: “here I am, come and help”

16. Antibodies
protection gained from the formation of antigen-antibody complexes basically comes down to the tagging of foreign cells and molecules for destruction by phagocytes and complement
Antibodies shown in different stains

17. Antibodies the antibody molecule is not damaging to the antigen
Melanoma antigens

18. Antibodies neutralization
blocks the adhesion of bacteria and viruses by bathing the surface of the cell with antibody
immobilization and prevention of adherence
antibodies binding to structures such as flagella and pili can interfere with mobility and attachment

19. Antibodies

20. Antibodies

21. Lymphoid System
in regards to the immune system the lymphatic system consists of tissues and organs that are designed and located to convey the B and T cells into contact with all antigens that enter the body

22. Lymphoid System this process is accomplished with the
lymphatic vessels
fluid of the lymphoid system called lymph
secondary lymph organs such as tonsils, spleen, lymph nodes

23. Lymphoid System primary lymph organs
bone marrow: the location of stem cells that will eventually become B and T cells, B cells mature in the bone marrow
thymus: maturation of the T cells
Lymph node
Bone marrow with leukemia
Healthy bone marrow

24. Lymphoid System
notice how completely our body is covered by the lymphoid system

25. Lymphocytes critical part of immune system responsible for
detection of foreign antigens
activate immune system
B lymphocytes
T lymphocytes
natural killer cells (NK cells)

26. B lymphocytes: B cells
antibody producing cells that respond to an antigen stimulation
develop from stem cells located in the red bone marrow of adults and the liver of a fetus
B Cells dividing

27. B lymphocytes: B cells
following maturation, they migrate to the lymphatic tissue
B cell in lymph node

28. B lymphocytes: B cells
once in place in the lymphoid organs, the B cells recognize antigens by means of the antigen receptors found on their cell surfaces
basis for antibody-mediated immunity
HIV antigens in yellow
B cells in red
B indicates a B cell

29. B cells

30. T lymphocytes: T cells key cellular component of immunity
develop from stem cells found in the bone marrow
precursors to T cells migrate to the thymus, where they reach maturity
human T cells

31. T lymphocytes: T cells
following maturity, T cells migrate to various lymph organs where they await contact with antigens
basis for cell-mediated immunity
T cells (on left – orange,
on right – gray) killing
cancer cells (on left- mauve.
on right – red)

32. T cells

33. Natural Killer Cells these cells are not immunologically specific
they do not need to be stimulated by an antigen

34. Natural Killer Cells
capable of destroying other cells, particularly viruses-infected cells and tumor cells
also can attack large parasites

35. Clonal Selection of Lymphocytes
speaks to the ability of B cells and T cells to differentiate to a population of cells capable of recognizing an infinite number of antigens
it is estimated that the human body has approximately 1 billion B cells, yet each individual cell is only capable of recognizing and responding to one antigen
B cell differentiation

36. Antibody-Mediated Immunity
humoral or antibody-mediated immunity involves antibodies that are produced by B cells
the term humoral is derived from the word “humors”, which is Latin for fluid
in response to foreign antigens, the B cell is activated to produce a clone of plasma cells and memory cells
plasma cells secrete antibodies
memory cells recognize pathogens from previous encounters
B memory cells are long lived and are ready to mount an attack the next time that specific antigen presents itself

37. Primary & Secondary Response
The body can make low levels of soluble antibody about one week after exposure to antigen. However, a second exposure to antigen produces a much faster response, and several orders of magnitude higher levels of antibody. The ability of antibody to bind antigen also increases in the secondary response. The memory of antigen and stimulated response is the basis for vaccination

38. Antibody-Mediated Immunity
the antigen-antibody complexes that are formed as a result of antibodies produce by B plasma cells attract phagocytes
Bacteria in green

39. Antibody-Mediated Immunity
phagocytosis destroys the pathogen and control of the disease is accomplished
Bacteria

40. Cell-Mediated Immunity
cell-mediated immunity involves specialized lymphocytes that respond to intracellular antigens
T cells are responsible for managing cell-mediated immunity
after maturation in the thymus, T cells differentiate into 2 groups
T-cytotoxic cells and T helper cells
Cytotoxic T cells
Helper T cell

41. Cell-Mediated Immunity
recognizes modified host cells (abnormal cells)
cell-mediated immunity is critical to controlling infections where pathogens reproduce in human cell
viruses, bacteria (rickettes), protozoa
important role in recognizing and destroying abnormal cells, such as tumor cells
T cells attacking cancer

42. Cell-Mediated Immunity
T cells do not recognize free antigens, the antigen must be presented by a modified host cell
augments antibody-mediated immunity
eliminates cells infected with viruses
antibodies can’t penetrate a virus within a host cell
T cells

43. Cell-Mediated Immunity
response to intracellular agents includes
antigen presentation
the antigen must be processed (degraded) and then individual peptides are displayed on the surface of a glycoprotein called a major histocompatibility complex (MHC) molecule
this antigen processing is done by antigen presenting cell (APC)

44. Cell-Mediated Immunity
cytotoxic T cells recognize the non-self cell and induce apoptosis (cell self death) in the viral infected or other microbial infected cell
this process also recognizes cancer cells and destroys them
unfortunately this process also recognizes and destroys non-self tissue or organ transplants

45. Cell-Mediated Immunity
T-helper cells, often referred to as CD4 cells, are responsible for the “second opinion” in immunity
T-helper cells judge the significance of the antigen presented by the antigen-presenting cells (APC)

46. Cell-Mediated Immunity
after binding to an APC, T- helper cells secrete cytokines that activate other T cells and B cells
interleukin-2
macrophage chemotactic factor
migration inhibition factor
macrophage activating factor
macrophage colony stimulating factor

47. Cell-Mediated Immunity
interleukin-2
stimulates the production of more T cells
macrophage chemotactic factor (MCF)
attracts macrophages (phagocytes) to the site of infection or abnormality
migration inhibition factor (MIF)
once at the infection site, MIF inhibits the macrophages from migrating elsewhere in the body
T cell (yellow) attracting
Macrophage (blue)

48. Cell-Mediated Immunity
macrophage activating factor (MAF)
once at the infection site, MAF alters the function of the macrophages
increases their lysosomal activities
increases their ability to kill
Macrophage using
pseudopodia to grab
pathogen
Macrophage ingesting bacteria

49. Cell-Mediated Immunity
macrophage colony stimulating factor (CSF)
regulates the production of macrophages at the site
Macrophage and T cell
Macrophage & E.coli

50. T-Helper Cells
T helper cells also play a role in activating B cells in antibody-mediated immunity

51. Click icon to learn more about T-cell dependent antigens
Helper T cells
Click icon to learn more about T-cell dependent antigens

52. Overview of Antibody-Mediated Immunity
initial response (bacteria with antigens enters the body)
B cells recognize
differentiate into plasma and memory cells
memory: recurring exposures
plasma produce antibodies
antigen/antibody complex forms
phagocytosis
control of disease

53. Overview of Cell-Mediated
modified host cell arrives
T cells activated
secrete cytokines
increase of T cell reproduction
attraction of macrophages (MCF)
inhibit migration (MIF)
activate phagocytosis (MAF)
control of disease

54. Overview of Immunity

55. Summary