Download White Blood Cells

White Blood Cells
Prepared by
Dr. Hamad ALAssaf
[email protected]
2015
Leukocytes / White Blood Cells
 Granulocytes (65%)
- neutrophils,
eosinophils, basophils
- formed in bone marrow
 Monocytes (5%)
- tissue
macrophages
- formed in bone marrow
 Lymphocytes (30%)
- formed
in lymph tissue
- life span: hours to years
Leukocytes Classification
• Granulocytes
– Neutrophils
– Eosinophils
– Basophils
Non- Granulocytes
- Monocytes
- Lymphocytes
• Polymorphonuclear
– Neutrophils
– Eosinophils
– Basophils
Mononuclear
- Monocytes
- Lymphocytes
• Phagocytes
– Neutrophils, monocytes
– Macrophages, eosinophils
Non-phagocytes
- Lymphocytes
- Basophils
Phagocytic Cells
1- Polymorphonuclear Neutrophils
- non-dividing, short-lived (6 hours to a few days)
- dominant number in bloodstream
2- Monocytes/Macrophages
- long-lived cells (months)
- do not circulate
- present in tissue, particularly in lungs, spleen, liver, lymph nodes
- tissue macrophage system
Actions of Phagocytic Cells
1. Margination
2. Diapedesis
3. Ameboid Motion
4. Chemotaxis
5. Phagocytosis
Actions of Phagocytic Cells
Phagocytosis
2. Engulfment
1. Binding
3. Phagosome formation
Acidification
proteolysis
MHC II
4. Lysosome fusion
6-Antigen
presentation
5 Membrane disruption
Cell-mediated Response to Inflammation
1. Tissue macrophages:
- already present in tissue
2. Neutrophil invasion:
- margination, diapedesis, chemotaxis
- stimulation of bone marrow to release stored leukocytes, 4-5 hours
3. Macrophage proliferation:
- invasion by circulating monocytes (several hours to increase size)
4. Stimulation of granulocyte and monocyte production:
- growth factors produced by tissue macrophages (TNF, IL-1, Cell stimulating factor)
NORMAL PRODUCTION
Production
INFECTION
Increased
Production
Marrow
pool
Bone
Decreased
marrow pool
Bone
Circulating and marginated pools
Blood vessel
Increased circulation
Increased margination
Blood vessel
Transmigration
Tissue
Tissue
Increased
Transmigration
Site of inflammation
Granulocytes
• EOSINOPHILS:
- ~ 2% of total white blood cells
- active against parasites, skin diseases, chronic infections
- phagocytic and immunomodulatory, decrease inflammation
- life span 5 days
• BASOPHILS:
~ 0.5% of total white blood cells
- basophils similar to mast cells
- release primarily histamine, some bradykinin
- release due to binding of IgE
- Life span a few hours to a few days
Important terms
• Leukopenia : decrease in the number of white
blood cells. example: bone marrow
suppression
• Leukocytosis : increase in the number of
white blood cells. example : bacterial
infections
• Leukemia
:
(cancerous)
uncontrolled
production of white blood cells
Neutropenia
Neutropenia: decreased number of neutrophils due to:
 Decreased production
 Increased neutrophil destruction (chronic infections)
Agranulocytosis: severe neutropenia due to:




production failure
due to irradiation
exposure to chemicals
drugs
Immunity
It is a special defense mechanism which is mobilized
when the body is invaded by a foreign organism.
Immunity
 Innate =
(present since birth)
- ability to resist damaging organisms and toxins
- skin, gastric acids, tissue neutrophils and macrophages,
complement
 Acquired = (developed by exposure to specific invading
agents).
- humoral ----> circulating antibodies
- cellular ----> activated cells
Sequence
- Dormant lymphocytes
- Invasion of body by foreign antigen
- Phagocytosis by macrophages
- Presentation of antigen to lymphocytes
Antigen
An antigen: is a substance that can induce an
immune
response
when
introduced
into
an
immunocompetent host and that can react with the
antibody produced from that response.
Lymphocytes
T- and B-Cells
T8-supressor
Pre-T
Cell
T-Cell
Thymus
T4-helper
Bone Marrow
Stem cell
Pre-B
Cell
B-Cell
Plasma Cell
Liver and
Bone
marrow
IgG IgA IgM IgD IgE
T-cells
 Cytotoxic Cells
kill infected cells
 Helper Cells ( CD-4 cells)
activate macrophages and B-cells
 Suppressor Cells
regulate activity