Immunology

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Immunology
Phagocytes
Killer T-cells
Macrophages
Natural Killer Cells
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Immune System

• Group of cells in the body that recognize foreign
  substances
• F(x) to neutralize or destroy all things
  non-self (pathogens or invaders)

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What is a Pathogen?

• Any toxin, living organism, or other agent that
  can cause disease.

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Immune Cells

• Immune cells circulate throughout the body in the
  blood system and the lymphatic system

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Lymphatic System

• A network of vessels that penetrate nearly every
  tissue of the body, and a collection of tissues
  organs that produce immune cells
• F(x)
• Fluid recovery from tissues
• Lymph fluid
• Immunity
• Lymph is filtered before returning to blood

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Lymph Tissues Organs

• Lymph Nodes
• Clean the lymph alert the immune system to
  pathogens
• Tonsils
• Guard against ingested orinhaled pathogens
• Thymus
• Produces T-cells
• Spleen (largest Lymph Organ)
• Monitors blood for foreign objects
• Recycles old RBCs

TONSIL
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Body Defense

• - Two Types
• Non-Specific
• Specific

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Non-Specific Body Defense

• Innate or inborn, not affected by prior exposures
• NOT specific for any invader
• Operates constantly

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Non-Specific Body Defense

• SKIN 1st Line of Defense
• Physical barrier prevents entry of pathogens
• Must beunbroken tobe effective
• Acidic, oily, sweat glandsinhibitsbacterial
  growth

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Non-Specific Body Defense

• MUCUS MEMBRANES
• Respiratory,Digestive,Urinary,Reproduction
  tracts
• F(x)
• To trap debris pathogens

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Non-Specific Body Defense

• HAIRS
• Nasal passage
• Traps debris pathogens
• CILIA
• Upper Respiratory Tract
• Traps debris pathogens

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Non-Specific Body Defense

• CELLULAR DEFENSE
• Activated when other defenses are breached
• Two Types
• Phagocytes
• Leukocytes

Phagocyte eating dying cells.
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Phagocytes

• Cells that recognize non-self items
• F(x) engulf or eat foreign debris
• Reside in lymph organs
• Travel to the site of infection, via the blood
  stream
• Macrophage a type of phagocyte

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Leukocytes (Natural Killer Cells)

• a.k.a. NK Cells
• WBCs police the blood lymph
• F(x)
• Bind to membrane of the invader, release
  chemicals, cause infected cell to lyse

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Non-Specific Body Defense

• CELLULAR (TISSUE) DEFENSE
• Inflammatory Response
• Fever

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Inflammation

• Local defensive response to tissue injury of any
  kind
• Response is directly at site of injury
• Helps to prevent spread of the damaging agent

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Inflammation

• The 4 Signs of Inflammation S.H.A.R.P.
• Swelling
• Heat
• ?
• All four of these due to fluid build-up
• ?
• Redness
• Pain

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Fever

• Abnormal elevation in body temp.
• Response to infection
• Stimulates phagocytes to go to work
• Heat kills many pathogens
• Increases the rate of enzymatic rxns

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Non-Specific Body Defense

• CHEMICAL DEFENSE
• Interferons (antiviral proteins)

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Interferons

• Secreted by virus-infected cell
• Stimulates non-infected cells to make proteins
  that block viral protein synthesis
• Slows infection to allow specific defenses to
  begin working
• Activates macrophages to eat (non-self) viral
  invaders

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Specific Body Defense

• Immunity ability to ward off a specific
  infection or disease
• Highly specific resistance to disease
• Process
• Particular invader recognized
• Switches on immune response
• Invader is remembered so that future invasions
  can be immediately fought

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Specific Body Defense

• Specific Body Defense is born out of the
  Lymphatic System
• i.e. Bone marrow ? makes B-cells, which make
  specific antibodies

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Antigens

• Irritant or pathogen molecule that react with
  antibodies
• Epitope region of antigen recognized by a
  specific antibody
• Stimulates formationof antibodies

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Antibodies

• Molecules that react with or bind to antigens
• Mark antigens for destruction by macrophages
• Form due to the exposureto a specific antigen

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Antibodies

• Made by B-cells
• Found in plasma, all body secretions
• Once present, allows immediate immune response to
  pathogens

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Antibodies

• Structure (most common)
• Composed of 2 heavy chains, 2 light chains
• Constant Variable regions
• Antigen-binding site

Variable region
Constant region
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Specific Body Defense

• Helper T-cells
• Attract other T-cells (Killer T-cells) and
  macrophages to an antigen
• Killer T-cells
• Directly attack kill pathogens, release
  chemicals to lyse cells

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Specific Body Defense

• Suppressor T-cells
• Stops immune response when antigen is
  successfully overcome

Scanning Electron Micrograph of a T-cell
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• Specific Non-specific Defenses work
• together to protect the body from
• disease-producing pathogens
• B-cells mature in bone tissue
• T-cells mature in thymus tissue

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Applications of Immune Response

• Immunization process that increases an
  organisms rxn to antigen therefore improves
  its ability to resist or overcome infection.
• Vaccine living or inactivated organism
• used to induce specific immunity

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Vaccines

• Attenuated agents
• Virus/bacteria that has beenmodified to be
  incapable ofcausing disease
• Inactivated agents
• Pieces or a whole organism that has been
  chemically inactivated
• Cant reproduce but retains antigenicity

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Immunity

• 3 Types
• Active
• Passive
• Cell Mediated

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Active Immunity

• When an individual responds to an antigen
• Resulting from vaccination against or
• Recovery from a natural infection
• Permanent Immunity

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Passive Immunity

• Antibodies produced from another organism
  injected into the body
• Temporary protection against disease

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Cell-Mediated Immunity

• Killer T-cells attack any cell not marked with a
  special protein(i.e. cells that are non-self)