The Immune System
• OverviewOverview– Systems involvedSystems involved– Cells involvedCells involved
• Non-specific ImmunityNon-specific Immunity• Specific ImmunitySpecific Immunity
– AntibodiesAntibodies– ComplementComplement– Immunology TutorialImmunology Tutorial
Host defense mechanisms
First line of defenseFirst line of defense: host ____________ and : host ____________ and chemical barriers (skin, mucous, tears, etc.)chemical barriers (skin, mucous, tears, etc.)
Second line of defenseSecond line of defense: phagocytes and : phagocytes and
______________________ (non-specific)______________________ (non-specific)
Third line of defenseThird line of defense: __________________ : __________________ immune reactionsimmune reactions
Systems involved in immune defenses
1) 1) BloodstreamBloodstream
2) 2) Lymphatic systemLymphatic system
3) 3) Reticuloendothelial (or mononuclear Reticuloendothelial (or mononuclear phagocyte) systemphagocyte) system -- support system of -- support system of _____________________ tissue fibers and _____________________ tissue fibers and endotheliumendothelium
4) 4) Extracellular fluidExtracellular fluid
Communicating systems
Communicating systems
Important blood cells involved in immune systems
Stem cellsStem cells -- undifferentiated cells which give rise to all the -- undifferentiated cells which give rise to all the others. Found in __________ ____________. Produce others. Found in __________ ____________. Produce erythrocytes (RBCs), erythrocytes (RBCs), leukocytesleukocytes (WBCs), and platelets (WBCs), and platelets
LeukocytesLeukocytes are generally divided into 2 groups: are generally divided into 2 groups: granulocytesgranulocytes (polymorphonuclear __________________) (polymorphonuclear __________________) and and agranulocytes agranulocytes (mononuclear leukocytes)(mononuclear leukocytes)Examples of granulocytesExamples of granulocytes: neutrophils (“microphage”), basophils, : neutrophils (“microphage”), basophils,
eosinophilseosinophils
Examples of agranulocytesExamples of agranulocytes: monocytes, lymphocytes: monocytes, lymphocytes
Granular leukocytesGranular leukocytes
ErythrocytesErythrocytes
Agranular leukocyteAgranular leukocyte
AgranulocytesLymphocytesLymphocytes
__________________________ -- derived from the thymus. -- derived from the thymus. Important in Important in cell-mediated immunitycell-mediated immunity..
__________________________ -- derived from bone marrow, -- derived from bone marrow, primarily. primarily. Important in Important in humoral immunityhumoral immunity..
Monocytes -- large, common, important in Monocytes -- large, common, important in ____________________ and specific immune ____________________ and specific immune functions. Non-circulatory (tissue-associated) functions. Non-circulatory (tissue-associated) monocytes are known as monocytes are known as macrophagesmacrophages. .
LymphocyteLymphocyte: note_____________ nucleus, little cytoplasm.: note_____________ nucleus, little cytoplasm. Is smaller than monocyteIs smaller than monocyte
NeutrophiNeutrophil l (a granular (a granular leukocyte): note leukocyte): note
granules and granules and ___________ nucleus___________ nucleus
MonocyteMonocyte: note unlobed, : note unlobed,
rounded nucleus and rounded nucleus and
apparent lack of granulesapparent lack of granules
Non-Specific Immune Reactions
• InflammationInflammation
• Phagocytosis (and presentation)Phagocytosis (and presentation)
• ComplementComplement
““Rubor” -- __________Rubor” -- __________““Calor” -- warmthCalor” -- warmth““Tumor” -- ____________Tumor” -- ____________““Dolor” -- painDolor” -- pain
Non-specific Immunity: Phagocytosis
• Carried out primarily by neutrophils and by Carried out primarily by neutrophils and by monocytes/macrophages (collectively called monocytes/macrophages (collectively called ‘_______________’)‘_______________’)
The scanning electron micrograph above, shows a human macrophage (gray) approaching a Streptococcus pyogenes (yellow). Riding atop the macrophage is a spherical lymphocyte. Both macrophages and lymphocytes can be found near an infection, and the interaction between these cells is important in eliminating infection.
Phagocytosis by Macrophages
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Phagocytic killing
Phagocytes Phagocytes shift from aerobic to shift from aerobic to
______________________________________ metabolism. Leads metabolism. Leads
to to drop in _________drop in _________, which activates , which activates
lysosomal enzymes.lysosomal enzymes.
Oxygen-dependent phagocytic killing
Phagocyte failure
Pathogens can neutralize phagocyte products:Pathogens can neutralize phagocyte products: __________________________________________ produces carotenoids produces carotenoids
which quench singlet oxygenwhich quench singlet oxygen Mycobacterium sp.Mycobacterium sp. can grow can grow withinwithin
macrophages using glycolipids in their cells macrophages using glycolipids in their cells walls to scavenge toxic _________________ walls to scavenge toxic _________________ speciesspecies
Strep. pyogenesStrep. pyogenes and and Staph. aureusStaph. aureus produce produce leukocidinsleukocidins which destroy ________________. which destroy ________________.
Specific Immunity: Antibodies or Immunoglobulins
IgGIgG
The complement system““Complement” is an additional mechanism that is brought into play at Complement” is an additional mechanism that is brought into play at
several levels in _______ __________.several levels in _______ __________.Is a Is a cascadecascade of proteins which result in membrane permeation and cell death of proteins which result in membrane permeation and cell death
The Complement System: a Summary
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