What is specific resistance What are the forms and properties of immunity

1
What is specific resistance? What are the forms
and properties of immunity?
2
Specific Defenses

• Specific resistance (immunity)
• responds to specific antigens
• with coordinated action of T cells and B cells
• Immunocompetency

3
The Immune Response

• 2 main divisions
• cell mediated immunity (T cells)
• Defends against abnormal cells and pathogens
  inside cells
• antibody mediated immunity (B cells)
• Humoral immunity
• Defends against antigens and pathogens in body
  fluids (humors)

4
The Immune Response
Figure 2215 (Navigator)
5
4 Properties of Immunity

• Specificity
• Versatility
• Memory
• Tolerance

6
What are the mechanisms of T cell activation and
the differentiation of the major classes of T
cells?
7
Antigens

• Surface proteins identify pathogens or foreign
  compound
• Complete antigens have two functional properties
• Immunogenicity
• Reactivity
• contain regions (epitopes or antigenic
  determinants) that are recognized by lymphocytes

8

• antigens usually have many epitopes
• each induces production of specific antibodies or
  activates a type of T cell
• Haptens
• partial antigens
• reactivity but no immunogenicity

9
(No Transcript)
10
MHC Proteins

• Genetically coded
• major histocompatibility complex (MHC)
• differs among individuals
• membrane glycoproteins that bind to antigens
• T cells only recognize antigens that are bound to
  these glycoproteins

11
2 Classes of MHC Proteins

• Class I
• found in membranes of all nucleated cells
• Class II
• found in membranes of antigen-presenting cells
  (APCs)
• found in lymphocytes

12
Class I MHC Proteins

• Pick up small peptides in cell and carry them to
  the surface
• T cells ignore normal peptides
• abnormal peptides or viral proteins activate T
  cells to destroy cell

13
Class II MHC Proteins

• Antigenic fragments
• from antigenic processing of pathogens
• Foreign antigens inserted in cell membrane to
  stimulate T cells

14
Class I MHC Proteins
Figure 2216a (Navigator)
15
Class II MHC Proteins
Figure 2216b
16
Antigen Recognition

• Inactive T cell receptors
• recognize Class I or Class II MHC proteins
• recognize a specific antigen
• Binding occurs when MHC protein matches antigen

17
CD8 Markers

• Found on cytotoxic T cells and suppressor T cells
• Respond to antigens on Class I MHC proteins

18
CD4 Markers

• Found on helper T cells
• Respond to antigens on Class II MHC proteins

19
3 Main Types of T Cells

• Cytotoxic T cells (Killer T cells)
• Directly attack and destroy pathogens
• Helper T cells
• Activate killer T cells and B cells
• Suppressor T cells
• Suppress activity of T cells and B cells

20
What are the mechanisms of B cell activation and
the differentiation of plasma cells and memory B
cells?
21
B Cell Sensitization

• Corresponding antigens in interstitial fluids
  bind to B cell receptors
• Taken into cell and processed
• reappear on surface, bound to Class II MHC protein

22
B Cell Activation

• Helper T cell binds to MHC complex
• secretes cytokines that promote B cell activation
  and division
• Activated B cell divides into
• plasma cells
• memory B cells

23
(No Transcript)
24
Forms of Humoral Immunity

• Innate
• present at birth
• Acquired
• after birth

25
Acquired Immunity

• Active
• antibodies develop after exposure to antigen
• Passive
• antibodies are transferred from another source

26
Active Immunity

• Naturally acquired
• through environmental exposure to pathogens
• Induced
• through vaccines containing pathogens

27
Passive Immunity

• Naturally acquired
• antibodies acquired from the mother
• Induced
• by an injection of antibodies

28
Forms of Immunity
Figure 2214
29
What are the primary and secondary responses to
antigen exposure?
30
Primary and Secondary Responses to Antigen
Exposure

• First exposure
• produces primary response
• Next exposure
• triggers secondary response
• more extensive and prolonged
• memory cells already primed

31
What is the structure of an antibody, and what
types of antibodies are found in body fluids and
secretions?
32
Antibody Structure

• 2 pairs of polypeptide chains
• 1 pair of heavy chains
• 1 pair of light chains
• Each chain contains
• constant segments
• variable segments

33
Antibody Structure
Figure 2221a, b
34

• 5 types of antibodies (immunoglobins)
• IgG
• IgE
• IgD
• IgM
• IgA

35
What are the functions of antibodies and how
are they performed?
36
Functions of Antibodies

• PLAN
• Precipitation
• Lysis by complement activation
• Agglutination
• Neutralization

37
(No Transcript)
38
What are the origins of autoimmune disorders,
immunodeficiency diseases, and allergies, and
what are some examples of each?
39
Immune Disorders

• Immunodeficiency disease
• Autoimmune disorders
• Allergies

40
Autoimmune Disorders

• A malfunction of system that recognizes and
  ignores normal antigens
• Multiple sclerosis destroys white matter of
  brain and spinal cord
• Systemic lupus systemic disease affects most
  body systems
• Rheumatoid arthritis destroys joints

41
Immunodeficiency Diseases

• Problems with embryological development of
  lymphoid tissues
• can result in severe combined immunodeficiency
  disease (SCID)
• Viral infections such as HIV
• can result in AIDS
• Immunosuppressive drugs or radiation treatments
• can lead to complete immunological failure

42
Allergies

• Inappropriate or excessive immune responses to
  antigens
• Allergens
• antigens that trigger allergic reactions