MATERI KULIAH IMUNOLOGI

1. Immunology I:
Basic Principles of Adaptive Immunity
and Immunization
Gusti Ayu Rai Saputri,M.Si., Apt.
.
Copyright © 2005 by John Wiley & Sons, Inc.

2. Immunology and Immunity
• Immunity: refers to the ability of an organism to recognize
and defend itself against infectious agents
• Susceptibility: opposite of immunity, is the vulnerability of
the host to harm by infectious agents
• Immunology: the study of adaptive immunity and how the
immune system responds to specific infectious agents and
toxins
• Immune system: consists of various cells, especially
lymphocytes, and organs such as the thymus gland, that help
provide the host with specific immunity to infectious agents

3. Types of Immunity
• Innate immunity (genetic): exists because of genetically
determined characteristics
• All humans have immunity to many infectious agents that
cause disease in pets and domestic animals
• Adaptive immunity (acquired): immunity obtained in some
manner other than heredity
• Naturally acquired adaptive immunity is most often obtained
by having a specific disease
• Artificially acquired adaptive immunity is obtained by
receiving an antigen by injection of vaccine or immune serum

4. The various types of immunity: nonspecific immunity is
largely innate, whereas specific immunity is acquired

5. Characteristics of the Immune System
• Antigen: a substance the body identifies as foreign and toward
which it mounts an immune response
• Large, complex proteins can have several epitopes, or antigenic
determinants (areas on the molecule to which antibodies can bind)
• Hapten: a small molecule can act as an antigen if it binds to a
larger protein molecule
• Antibody: a protein produced in response to an antigen that is
capable of binding specifically to the antigen
• Titer: the quantity of a substance needed to produce a given
reaction

6. A typical antigen-antibody reaction: antibodies bind to
specific chemical groups or structures, called epitopes or
antigenic determinants

7. A typical antigen: antibody reaction: gram-negative bacterial
pathogen may have several antigens, or immunogens (flagella,
pili and cell wall)

8. Cells and Tissues of the Immune System
• Specific immune responses are carried out by lymphocytes
which develop from stem cells as do other white blood cells,
red blood cells, and platelets
• B lymphocytes (B cells): lymphocytes are processed and
mature in tissue, referred to as bursal-equivalent tissue
• T lymphocytes ( T cells): stem cells migrate to the thymus,
where they undergo differentiation into thymus-derived cells
• Natural killer cells (NK): found in tissues and circulating in
blood and nonspecifically kill cancer cells and viral-infected
cells

9. Differentiation of stem cells into B cells and T cells.
This occurs in the bone marrow and thymus.

12. The Bursa of Fabricus
In chickens this is where B cells develop

13. Dual Nature of the Immune System
• Lymphocytes give rise to two major types of
immune responses
1. Humoral immunity: carried out by
antibodies circulating in the blood
2. Cell mediated immunity: carried out by T
cells and occurs at the cellular level

14. Clonal selection hypothesis: One of many B cells responds
to a particular antigen and begins to divide, thereby
producing a large population of identical B cells (a clone)

17. Recognition of Self vs. Nonself
• For the immune system to respond to foreign substances, it
must distinguish between host tissues and substances that are
foreign to the host
• Self is normal host and nonself are foreign substances
• The clonal selection hypothesis (figure 17.5) and clonal
deletion hypothesis (figure 17.6)
• This mechanism removes lymphocytes that can destroy host
tissues and thereby creates tolerance for self

18. Clonal Delection: this process,which takes place in the bone
marrow and thymus, removes those lymphocytes that have
receptors for self antigens

19. Properties of Antibodies (Immunglobulins)
• Y-shaped protein molecules composed of four
polypeptide chains – two identical light (L) chains and
two identical heavy (H) chains
• Constant regions: determines the particular class that
an immunoglobulin belongs to
• Variable regions: each chain have a particular shape
and charge that enable the molecule to bind a
particular antigen

20. Antibody Structure

23. Classes of Immunoglobulins
• Five classes of immunoglobulins have been identified in
humans and other higher vertebrates
1. IgG: the main class of antibodies found in the blood
accounts for as much as 20% of all plasma proteins
2. IgA: occurs in small amounts in blood and in larger
amounts in body secretions (tears, milk, saliva and mucus)
3. IgM: found as a monomer on the surface of B cells and is
secreted as a pentamer by plasma cells
4. IgE: has a special affinity for receptors on the plasma
membranes of basophils in blood or mast cells in tissues
5. IgD: found mainly on B-cell membranes and is rarely
secreted

24. How B Cells Build Diverse Antibodies

25. The Structures of the Different Classes of Antibodies

30. Primary and Secondary Responses
• In humoral immunity the primary response to an
antigen occurs when the antigen is first recognized by
host B cells
• Primary response of B cells can occur by two
mechanisms:
1. B cells can be activated by binding antigen,
proliferating and forming plasma cells (T-independent
antigens)
2. Produces IgM antibody and no B memory cells are
formed (T-dependent antigens)
• Secondary response: when an antigen recognized by
memory cells enters the blood

31. Primary and Secondary Responses to an Antigen

32. Primary and Secondary Responses to an Antigen

33. Antibodies produced
by humoral immune
responses eliminate
foreign agents in three
ways:
1. Neutralization
2. Opsonization
3. Immune complexes

34. Summary of Humoral Immunity

35. Monoclonal Antibodies
• Antibodies produced in the laboratory by a clone of
cultured cells that make one specific antibody
• Myeloma cells (malignant cells of immune system) are
mixed with sensitized lymphocytes
• Lymphocytes are used because each makes a
particular antibody
• Hybridoma: when two cell types are mixed in
cultures, they can be made to fuse with one another to
make this cell type

36. Production of monoclonal antibodies: only the hybridoma cells grown in
culture will survive, because any unfused spleen cells cannot divide, and any
unfused mouse myeloma cells cannot get the nutrients they need to grow

39. Cell-Mediated Immunity
• Involves the direct actions of T cells
• T cells interact directly with other cells that display
foreign antigens
• Involves the differentiation and actions of different
types of t cells and production of chemical mediators
(cytokines)
• Cytokines: lymphokines and interleukins

40. The Reactions in Cell-Mediated Immunity

42. Cell-Mediated Immune Reaction
• Involves the response of T lymphocytes
• T cells cannot be activated directly by antigens
• Macrophages that have processed an antigen secrete
the lymphokine interleukin-1 (IL-1), which activates
T helper cells
• T helper cells secrete interleukin-2 (IL-2) and
activate delayed hypersensitivity cells and cytotoxic
killer cells
• IL-1 and IL-2 cause undifferentiated cells to become
natural killer cells

43. Types of T cells: After T cells are challenged by antigens, the
cells differentiate into one of several types of functioning T cells

44. Summary of Cell-mediated Immunity: “CD”
stands for cluster of differentiation

45. • Active immunization is the process of inducing active
immunity
• Can be conferred by administering vaccines or toxoids
• Vaccine: a substance that contains an antigen to which
the immune system responds
• Toxoid: an inactivated toxin that is no longer harmful,
but retains its antigenic properties
Immunization

46. Recommended Immunizations
• Three vaccines that immunize against seven
diseases are currently recommended in the
U.S
1. DTaP vaccine: contains diphtheria toxoid,
acellular pertussis (whooping cough), and
tetanus toxoid
2. Poliomyelitis vaccine
3. MMR vaccine contains live rubella, rubeola,
and mumps virus

47. Vaccination mark from inoculation with BCG vaccine: This
vaccine is used in some countries to immunize against
tuberculosis

48. Passive Immunization
• Ready-made antibodies are introduced into an
unprotected individual
• Because antibodies are found in serum, these
products are often called antisera
• Established by administering a preparation such as
gamma globulin, hyperimmune serum, or an
antitoxin that contains large numbers of ready-made
antibodies

49. Colorized SEM of a small T lymphocyte attacking
two large tumor cells

50. How the Immune System Combats Viruses

55. How Antigens of Parasitic Protozoans Thwart
the Immune System