ACQUIRED IMMUNE RESPONSE Vaccination or immunization Active case

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ACQUIRED IMMUNE RESPONSE Vaccination or
immunization Active case Antigen - foreign
substance, usually protein or carbohydrate,
cell component Antibody - blood protein produced
in response to a foreign substance
IMMUNOGLOBULIN System with a memory
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The Lymphatic System Reticuloendothelial System
(RES) Overlapping organ systems
Lymphatic lymphocytes supporting structures
Bone marrow Lymph nodes Thymus Spleen
RES macrophages related phagocytes Bone
marrow Lymph nodes Thymus Spleen Liver
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Bone marrow - stem cells which give rise to all
blood cells B lymphocytes - mature in bone
marrow T lymphocytes - mature in
thymus Macrophages Primary lymphoid organs
Thymus - T lymphocyte maturation commitment to
respond to specific antigen receptor on cell
surface 5 survive thymus atrophies at
puberty Bone marrow - B lymphocyte
differentiation receptor on surface
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Secondary lymphoid organs Spleen primary
site of antibody production traps
concentrates foreign antigens B
lymphocytes 50 of spleen cells T
lymphocytes 30-40 of spleen cells Lymph
nodes traps concentrates foreign antigens
site of some antibody production
macrophages, B T lymphocytes
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IMMUNE SYSTEM RESPONSE Antibody-mediated or
Humoral response B lymphocytes antibody
producing cells supported by macrophages
some T lymphocytes Cell-mediated response T
lymphocytes (subpopulation of T lymphocytes)
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ANTIGEN Carbohydrate Protein
Nucleic acid? Small molecules - if attached
to protein Cell surface components MHC
major histocompatibility complex ABO - blood
typing system LPS lipopolysaccharide of
Gram-negative bacteria EPITOPE Reactive
portion or face HETEROPHILE ANTIGEN Many
faces stronger response
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Route of antigen removal 1. Bloodstream to
spleen 2. Lodge in epidermal, dermal or
subcutaneous tissue inflammatory
response antigen carried by macrophages to lymph
nodes/spleen 3. Gastrointestinal or
Respiratory tract macrophages lymphocytes
interact antibody formed macrophages transport
to other tissues
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ANTIBODY STRUCTURE 4 polypeptide chains - 2
heavy, 2 light constant regions variable
regions Papain cut Fc Fab
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ANTIBODY STRUCTURE 4 polypeptide chains - 2
heavy, 2 light constant regions variable
regions Papain cut Fc Fab Antibody
classes - based on heavy chain IgA IgD IgE IgG
IgM
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Immunoglobulin G - IgG 80 of serum
antibodies cross walls of blood vessels,
placenta protect against bacteria, viruses,
toxins enhance phagocytosis
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Immunoglobulin M - IgM 5-10 pentamer first
antibody produced ABO reactive antibody
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Immunoglobulin A - IgA secretory antibody
tears, saliva, breast milk monomer in serum,
dimer in secretion prevent attachment to mucosa
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Immunoglobulin D -IgD surface receptor for B
lymphocytes Immunoglobulin E - IgE exaggerated
response binds to mast cells and basophils
histamine release
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ANTIBODY FORMATION Time course primary response
- delayed, short-lived IgM first, then
IgG secondary response - anamnestic response,
rapid, strong
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ANTIBODY FORMATION B lymphocytes formed
mature in bone marrow maturation
produce antibody molecule, surface receptor
stimulation antigen binds receptor B
lymphocyte activated by immune system
multiplication forms clone of cells, clonal
selection plasma cells memory cells
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Role of other cells Macrophages - Antigen
Presenting Cell (APC) engulf antigen cut to
epitopes epitopes bond to MHC class II on
surface T cell with appropriate receptor
recognizes MHC epitope (CD4 receptor
on T cell) APC secretes Interleukin 1 (IL-1),
activating T cell T cell secretes other IL
molecules Il-2 IL-4 activate T cell,
causing proliferation release or IL-4 IL-5
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Superantigens Staphylococcus enterotoxin,
TSST some viruses Regular antigen
processed by macrophages epitopes on
surface with MHC interact with lymphocytes
with appropriate receptor Superantigen
binds directly to MHC massive lymphocyte
activation (up to 20 of T cells) high
levels of cytokines/lymphokines released Very
strong immune response systemic toxicity
suppression of normal immune response
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Antigen Antibody Reactions Toxins
neutralized, then destroyed (Antitoxin)
Soluble antigens precipitation Cells
aggregation Complement activation
complement fixation activate neutrophils initiat
e inflammatory response lyse cells containing
antigen Activate phagocytosis
Opsonization Serum with antibodies - Antiserum