[Ref: WG21:p518-523]
Normal level
= 4000 to 11000 per microliter
Granulocytes (polymorphonuclear leukocytes, PMNs) are the most numerous
* Includes neutrophil, eosinophil, and basophil
Lymphocytes
* Large round nuclei and scanty cytoplasm
* 20-40% of WBC
* N = 1500-4000 per microliter
Monocytes
* Kidney-shaped nuclei
* Agranular cytoplasm
* 2-8% of WBC
* N = 300-600 per microliter
Halflife = 6 hours
100 billion neutrophils are produced daily
Many neutrophils enter the tissues
* Attracted to endothelial surface by selectins
--> Roll along the surface
--> Binds firmly to neutrophil adhesion molecule (of the integrin family)
--> Squeezes through the walls between endothelial cells by a process called diapedesis
During inflammation, large numbers of neutrophils are produced and released from bone marrow
Neu
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Stopped at WG21:p520
@@ Will finish after viva and after reading some decent immunology book. WG is too brief!!!
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Principal opsonins that coat the bacteria = IgG and complement proteins
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IL-4 = Basophil differentiation
IL-5 = Eosinophil differentiation
IL-1, then IL-6, then IL-3, act to commit pluripotential uncommitted stem cells to committed progenitor cells
IL-1, IL-6, and TNF-alpha --> fever
IL-1 reduce appetite
=====
[WG21:p526]
Complement system
=====
[WG21:p527]
TH1 cells secrete IL-2 and gamma-interferon
--> Primarily cellular immunity
* IL12 encourage TH1 formation
TH2 cells secrete IL-4 and IL-5
--> Interact primarily with B cells (humoral immunity)
* IL4 encourage TH2 formation
IL1
* From macrophages
* Activate T cells and macrophages
IL2
* From TH1 cells
* Cause activated T cells to proliferate (autocrine) [WG21:p529]
* Activate lymphocytes, NK cells and macrophages
* Inhibited by glucocorticoids
Gamma Interferon
* From TH1 and NK cells
* Activation of macrophages
* Inhibit TH2 cells
Cytotoxic T cells = CD8 (heterodimer)
* Binds to MHC-I
T helper cells = CD4 (single protein)
* Binds to MHC-II
Class I MHC proteins = coupled to internally synthesized proteins (e.g. viral proteins)
* Cytotoxic T cells (CD8)
Class II MHC proteins = targets extracellular antigens (e.g. bacteria) that enter the cell by endocytosis and digested
* T helper cells (CD4)
Class I antigen = ALL nucleated cells
Class II antigen = present in antigen-presenting cells (B cells and activated T cells)
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[WG21:p530]
Functions of immunoglobulin
Central tolerance occurs in the thymus for T cells, the bone marrow for B cells