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Adaptive Immunity: Specific Defenses of the host
Ch 17
• Innate resistance• Immunity: ability of the body to resist
pathogens– Due to production of specific lymphocytes and
antibodies
• Acquired immunity– Naturally – active immunity – get it, get over it– Passive immunity – Mother to child, AB from
mother (short term)
Dual Nature of Adaptive Immunity
Figure 17.8
Dual Nature of Adaptive Immunity
• T and B cells develop from stem cells in red bone marrow
• Humoral immunity– B cells mature in the bone marrow
• Chickens: Bursa of Fabricius
– Due to antibodies
• Cellular immunity – Due to T cells– T cells mature in the thymus
ANIMATION Humoral Immunity: Overview
Artificially acquired immunity
• Vaccination
• Antiserum
• Gamma globulin (IgG purified)
• Antigen, anything that can cause an immunological response– Examples
Humoral vs.. cell mediated immunity
• Humoral is serum immunity
• Cell mediated depends on T cells
Antibody Structure
• The monomer is bivalent
• 4 ppt chains, 2 light and 2 heavy
• All contain a V region where antibody binding occurs
• Y or T shaped know where ab binds, know constant region.
• Fc or constant region binds to host cell or complement.
Haptens
Figure 17.2
Classes of Immunoglobulin
• IgG serum, passive immunity, neutralize, precipitate, opsonize
• IgM 5monomers on a chain, agglutination and complement
• IgA monomer in serum, dimmers in mucus, protects outer surfaces.
• IgD antigen receptors on B cells• IgE antigen receptors on mast cells and
basophiles.
• Apoptosis: programmed cell death, Lymphocytes that are no longer needed destroy themselves.
• Clonal selection: during fetal development, self reacting AB is destroyed. During sickness more AB is produced (will review later)
Types of WBC
Clonal Selection and differentiation of B cells
Results of antigen binding
• Neutralize
• Opsonizaiton
• Agglutination
• Fixing complement
• Precipitation
Immunological memory
• AB titer
• Plasma cells
• Memory cells
Monoclonal Antibodies
• Immortal cells that produce an antibody that binds to one haptin.
Production of Monoclonal AB (fig 18.2)
Antibodies can now be manufactured
• Used to tread diseases like cancer
• How are antibodies treated so that they do not produce an immune response?
All of the previous activities are due to B cells.
T cells and cell mediated Immunity
• Differentiate in the thymus gland (and others)
• Classified by cell surface receptors (CD4)
• Binds to antigen and APC by MHC
Practical applications of Immunology (ch 19)
• Vaccines– Heard immunity: if > 85% are immune to a
disease, the pathogen has difficulty spreading
• Types– Attenuated whole agent – non pathogenic– Inactivated whole agent – dead– Toxoids – inactivated toxin– Subunit vaccine –purified protein– Conjugated vaccine– DNA vaccine – MHC1 associated responses
How to make vaccines
• Animals
• Cell culture
• Chick embryos
• Recombinant vaccines are much safer
Disorders of the Human immune system
Defects
• Hay fever
• Transplant rejection
• Autoimmunity
• Infection
• carriers
Hypersensitivity
• Rx that lead to tissue damage
• Occur when person is sensitized
• 4 types
Autoimmune disease
• From loss of self tolerance• Self tolerance occurs during fetal development
– Clonal deletion– Clonal anergy
• Graves disease• Myasthenia gravis• Systemic lupus• Rheumatoid arthritis• Hashimotas disease• Insulin dependent diabetes
Types of T cells
• Classified by certain glycoproteins on surface (clusters of differentiation (CD))
• Th –T helper-CD4– Recognise an antigen presented on the
surface of a macrophage and activate it.
• Tc – Cytotoxic T cells –CD8– When activated by cytokines from the Th cell
will change to kill self altered cells
• Tr – Regulatory T cells – (turn down immune response)
Cytotoxic T cells are transformed into CTL’s by a cell
with markers on it.
The MHC antigen complex induces a toll-like receptor
Organisms like large paracites that are too large for ingestion by phagocytic cells must be attacked externally