Types of Immunity

1
Types of Immunity

• Innate vs. Acquired
• Active vs. Passive
• Natural vs. Artificial

2
Antigens

• Antigens
• Epitopes
• Haptens

3
Antibodies and Cells

• B lymphocytes
• T lymphocytes
• 4 sub-types
• Natural Killer cells

4
Nature of the Immune system

• Humoral Immunity
• Cell-mediated Immunity
• Cell lysis, apoptosis
• Foreign eukaryotic cells

5
General Immune System Properties

• Self versus Non-self Recognition
• Maturation leads to ________________
• Defects _______________________
• Specificity
• Random gene rearrangements create potential
  binding sites for antigens
• Some cross-reactivity

6
General Immune System Properties

• Diversity
• Over 1 billion antigen binding sites are possible
• Memory
• Sub-populations of stimulated lymphocytes remain
  in lymph nodes to provide a faster, larger
  response on second antigen encounter
• Basis of Immunity or the anamnestic (secondary)
  response

7
Nature of the Immune systemClonal stimulation

• B lymphocyte binds ________
• Bound Ag is engulfed and fragmented within the B
  cell
• Ag fragments ____________________________ (MHC
  II) proteins together presented or processed
  antigen
• Triggers __________________ (IL-2) production
  from T cells
• This stimulates B cells further and creates
  memory cells
• Known as _______________________, usually proteins

8
Antibody Anatomy

• Heavy/Light Chains
• Variable/
• Constant Regions
• Antigen Binding Site
• Disulfide Bridges

9
Immunoglobulin Classes

• Ig G
• IgA
• Ig M

• Ig E (reagin)
• Ig D

10
Immune Memory

• Primary Response
• IgM initially
• IgG detectible in 2-3 weeks
• Levels may drop after initial exposure
• Memory cells persist
• Secondary Response
• Much larger response of IgG
• Protection against invading microbes and toxins

11
Antigen Types

• T-independent
• No helper T cells
• No memory cells are created
• Only IgM
• Carbohydrate Ag, often capsular on bacteria
• T-dependent
• Needs helper T cells
• Creates memory B cells
• IgM and IgG
• Protein Ag

12
Effects of Ag/Ab Reactions

• Agglutination
• Reduction of target count
• Neutralization
• Viral and bacterial binding sites for host cell
  attachment are blocked

• Complement-mediated effects
• FC fragment (Constant region) activates
  complement
• Cytolysis
• Opsonization
• Increased inflammation

13
Monoclonal Antibodies

• MAbs
• Multiple myeloma cells normal lymphocytes
• Hybrid cells are
• Immortal in large-scale cell culture
• Specific Ab producers
• Uses
• Diagnostic
• Pregnancy
• Strep. Throat
• Chlamydia STD
• Anticancer
• Chemo agents may be attached
• Anti-tissue rejection
• Allergies to mouse proteins are a challenge
• Humanized Mabs

14
Cell Mediated Immunity

• Activation
• Processed antigens presented alongside MHC
  proteins
• TH cells are activated by Ag MHC II, antigen
  presenting dendritic cells, B cells or
  macrophages
• TC cells are activated by Ag MHC I , usually
  infected cells with intracellular virus or
  bacteria, transformed cells or transplant cells
• Memory T cells can form

15
T Cell Types

• Helper T cells (TH) release lymphokines
• IL-2
• stimulates Ab production
• Activates TC cells
• Gamma IFN
• Co-ordinates inflammatory response
• Antiviral and anti-tumor
• Delayed Hypersensitivity T cell (TD)
• TD cells release lymphokines that control
  macrophage movement/inflammation

16
T Cell Types (cont.)

• Cytotoxic T cells (TC)
• Produce Perforin proteins
• Lyse virally infected cells
• Natural Killer cells
• Produce Perforin proteins
• Lyse tumor and bacterially infected cells
• Activated by lack of MHC proteins on cell
  membranes, no clonal stimulation

17
Mucosal Immune System

• Mostly IgA production
• 400 square meters (4500 square feet!)
• Gut, GUT, Resp. tract

18
Factors Modifying the Immune System

• Disorders/Injuries
• Genetic tendencies
• Genetic diseases
• Environment
• Seasonal
• Pollution
• Rediation

• Lifestyle
• Diet
• Exercise
• Addictions
• Age
• Middle life most healthy

19
Immunization

• Active
• Ag administration
• Toxoid or microbial structural molecule
• Live vaccines provide longer protection
• Route of administration affects protection level

• Passive
• Ab administration
• Temporary, protection declines
• Will affect the course of a disease
• Allergic reactions are commonest drawback

20
Future Considerations

• Criteria for new vaccines

21
Immunity to Specific Pathogens

• Bacteria
• Viruses

• Fungi
• Protozoa/Helminths