IMMUNOLOGY BASICS Lactation Biology Animal Science 337

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IMMUNOLOGY BASICSLactation BiologyAnimal
Science 337

• Leo Timms
• Iowa State University

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MEANS OF AQUIRING IMMUNITY

• ACTIVE make own antibody
• chance encounter
  w/Ag
• a) natural
• pregnancy
• vaccination
• b) artificial
• introduce Ag via
  trt.

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MEANS OF AQUIRING IMMUNITY

• PASSIVE transfer preformed antibody
• a) natural mother to fetus
• (6 mo protection)
• placental vs. colostral
• b) artificial immune therapy

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Type of immune response

• Innate
• defense we are born with
• phagocytic cells
• complement proteins
• anatomical
• physiological

• Adaptive/acquired
• defense that develops with exposure/time
• serum antibodies
• T cells (CMI)

1st line of defense!!!
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Mechanisms of immunity

• Cellular
• cells responsible for protection
• lymphocytes
• phagocytes

• Humoral
• antibodies (in serum) are responsible for
  protection

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• large cell (10-25 um dia)
• main purpose phagocytosis / kill
• act non specifically
• chemotactic capability
• potent phagocytosis when activated
• by T lymphocytes (lymphokines)
• Express Ag on surface to T / B cells

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• multilobulated nucleus
• lysosomal granules
• phagocytosis and kill
• 1st white blood cell to infection site
• die and release contents
• irritate surrounding tissue / recruit cells
• Phago. improved by opsonization with Ig

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Inflammation part of innate immunity
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• poor at phagocytosis
• granules contain histamine / serotonin
• vasodilators / permeability factors
• requires binding of 2 IgE for release

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lymphocytes

• small (5 15 um)
• No lysosomes all brain until activated
• distinguish self from non self
• specific recognize specific antigens
• MEMORY
• need presentation of Ag by macrophage

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• interactions
• - antigen
• - macrophage
• - T cell (Th)
• - cytokines
• T helper (Th)
• T suppressor
• T killer
• others

• interactions
• - antigen
• - macrophage
• - T cell (Th)
• - B cell
• - cytokines

cytokines
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CYTOKINES / LYMPHOKINES

• Small polypeptide messengers
• very powerful in low doses
• multiple uses
• hormones
• Interleukins
• Interferon viral
• Colony Stimulating factors GCFS
• Tumor Necrosis Factor (TNF)
• inflammation / cell movement / traffic

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OTHER IMMUNE FACTORS

• Complement 9 specific serum proteins
• - interaction of components provide
• numerous biological events
• Lactoferrin Iron binding protein
• competes with bacteria for iron
• Lactoperoxidase ( LP/ SCN- / H2o2 syst.)
• antioxidant / oxygen radicals

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HUMORAL IMMUNITY (Ab or AMI)

• Antigen Macrophage T cell B cell
• Antibodies or Immunoglobulins
• SPECIFICITY!
• MEMORY
• (immunity short, long, or no term)

cytokines
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L light chain H heavy chain
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Functions

• Variable region (Fab) bind specifically-neutralize
  , ppt or agglutinate
• antigen binding region
• Constant region (Fc)
• - activate effector cells or
• complement
• - opsonin end

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Antibody Isotypes-5
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• Principle Ab in serum
• 14 18 mg / ml
• IgG1 11 mg/ml
• IgG2 7 mg/ml
• fixes complement
• late response to Ag

IgG
IgG1 IgG2

• IgG1
  IgG2
• selective transfer (colostrum) 10 opsonin
• fetal / neonatal defense for
• toxin inactivation
  phagocytosis
• principal milk / colostrum Ig
• (farm species)

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Opsonization

• Free IgG binds Fc receptors with low affinity
• IgG bound to Ag, binds to Fc receptors with high
  affinity
• Cross-linking receptors sends signal

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• largest Ig
• pentamer
• serum (1-3 mg/ml)
• fixes complement
• 1st Ig produced
• to Ag challenge!

IgM

• Binds to mast cells
• basophils
• ACTIVATION
• RELEASE OF
• histamine - serotonin

IgE
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• 3 different forms in serum
• different form in secretion ( secretory piece)
• serum 1-3 mg/ ml
• activates complement serum (yes) milk (no)

IgA
Secretory piece

• local immunity and secretions
• prevents bacterial adherence
• maternal milk very important
• primary Ig in colostrum (humans)!

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