WHITE BLOOD
CELLS
LEUKOCYTES
Dr. Taj
PLASMA
CELLS
WHITE BLOOD CELLS ARE
VERY IMPORTANT
WHY
PATHOGENS
INFECTIONS
IMMUNITY
Innate immunity
(non specific)
Examples:
• Phagocytes
• Complement
• Barriers
Acquired immunity
(specific)
Humoral
Antibody
mediated
B lymphocytes
Cell mediated
T lymphocytes
TYPES (CLASSIFICATION)

Granulocytes




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Polymorphonuclear leukocytes (PMNs)
Neutrophils
Eosinophils
Basophils
Agranulocytes

Lymphocytes



T lymphocyte
B lymphocyte
Monocytes  macrophage system
CLASSIFICATION
GRANULOCYTES
AGRANULOCYTES
Concentration (Normal Counts)
Cell
Total WBC
Granulocytes
Neutrophils
Eosinophils
Basophils
Lymphocytes
Monocytes
Approximate
Normal range
(/µL)
4000-11000
3000-6000
150-300
0-100
1500-4000
300-600
Percentage of
Total WBC
--50-70
1-4
0.4
20-40
2-8
Life span of leukocytes:
 Granulocytes  4-8 hours
 Monocytes  10-20 hours
 Lymphocytes & macrophages 
months & years
FORMATION
GENESIS
Genesis of blood cells
Genesis of white blood cells
BARRIERS
Lines of Defense
Response to Inflammation

1st line of defense – Tissue macrophages &
Physical Barriers
 2nd line of defense – Neutrophil Invasion of the
inflamed area
 3rd line of defense – Monocytes –macrophage
invasion of inflamed area

4th line of defense – Increased production of
granulocytes and Monocytes by Bone marrow
MONOCYTES





No Granules but Vacoules
Size: 15-20 µm
More Efficient than Neutrophils
Life span: 10-20 hours in blood
Two types: Mobile & Fixed
RESTING
MACROPHAGE
ACTIVATED
MACROPHAGE
ACTIVATED
MACROPHAGE
Reticuloendothelial System
Monocyte/Macrophage System
TISSUE MACROPHAGE SYSTEM
Monocytes
 Mobile macrophages
 Fixed tissue macrophages
 Specialized endothelial cells in bone
marrow, spleen and lymph nodes

Reticuloendothelial System
Monocytes/Macrophage System
Examples are: 1. Skin and Subc tissues (Histiocytes)
2. Lymph Nodes
3. Alveolar macrophages
4. Liver sinuses (Kupffer Cells)
5. Spleen & Bone marrow
6.
Microglia in Brain
Tissue macrophages in Liver sinuses
Tissue macrophages in Lymph Nodes
Tissue macrophages in Spleen
NEUTROPHILS
Most Abundant WBCs 60-70 %
 Size: 15-20 µm
 Nucleus: Multilobed 2-5 lobes
 Life span: 6-8 hours

DEFENSIVE PROPERTIES OF
MACROPHAGES & NEUTROPHILS
1.
2.
3.
4.
5.
Diapedesis
Chemotaxis
Opsonization
Degranulation
Phagocytosis & Digestion
PMNs Digestive System
(Antimicrobial system)
ENZYMATIC
Granules
 Heparin
 Histamine
 Bradykinin
 Serotinin
 Defensins
 Lysosomal enzymes
 Slow reacting substance
of anaphylaxis
PMNs Digestive System
(Antimicrobial system)
NON ENZYMATIC
respiratory burst
 O2 Free Radicals (O-2, H2O2, -OH)




NADPH-oxidase
Myeloperoxidase
Cl-  HoCl
Hypochlorous acid “very toxic”
Feed Back Control
of Macrophage
& Neutrophil
response
IMPORTANT TERMS
 Leukocytosis
 Neutrophilia
 Pus
 Leukopenia
 Leukemias
Formation of Pus
Dead Neutrophils
 Dead Macrophages
 Necrotic tissue

Inflammation
Is an Innate response
When tissue injury occurs by bacteria,
trauma, chemical or heat, multiple
substances are released by injured tissue
that cause dramatic secondary changes in
the injured tissue. The entire complex of
tissue changes is called Inflammation
EOSINOPHIL



Granules contain arginine rich protein, which
take acid dye (eosin)
Function: Phagocytosis
Chemotaxis: attracted towards chronic
inflammation


Neutralises allergic products such histamine, 5-HT,
Ag-Ab complex, bradykinin (allergic disease of skin
&lungs)
Phagocytosis is same as neutrophil, but less
efficient
Eosinophils cont,

High eosinophil count:
 Parasitic
(hook worm, ascaris,
bilharzia)
 Allergic (asthma, rhinitis, drug
reaction)
 Dermatological diseases
BASOPHILS



Weak phagocytic cells
Granules contain polysaccharide
granules > base methylene blue color.
Similar to mast cells releases its
granules containing heparin, histamine,
5HT. Which causes inflammation
reaction
IMMUNITY
Protect the body against damages caused by
foreign organism e.g. bacteria, viruses
transplanted incompatible tissue or organs
IMMUNE CELLS

Cells which recognized foreign
organism (antigen) by receptors
on its surface and respond to it:
1.
2.
T-Lymphocytes
B-Lymphocytes
Immune response

Lymphocytes respond to antigen
either by:
1.
2.
Producing antibodies (Blymphoctes) to attack foreign
antigen (humoral immunity)
Cellular killing of foreign invading
organism (cellular immunity) by Tlymphocytes
ENEMIES
Bacterias, Viruses, Fungi, Parasites
Antigens
Large > 8000, complex, unique molecule that
triggers a specific immune response against
itself when it gains entry into body.
•Foreign ness
•Molecular size
•Chemical structure
•Antigenic determinants (Epitopes)
Antibody
Globulin molecules in plasma
which are capable of attacking the
invading agent.
EXAMPLES:
IgG, IgA, IgM, IgD, IgE
Types of lymphocytes
T lymphocytes
1. Helper T-cells.
2. Cytotoxic T-cells.
3. Suppressor T-cells.
B lymphocytes
B-lymphocytes
•Plasma cells
•Memory Cells
Humoral immunity




B-lymphocytes recognize foreign organism
by its surface receptors
Interact with antigen>>> proliferation of
B-lymphocytes to plasma cells
Plasma cells secrete the specific antibody
to destroy the antigen
Some of this plasma cells will be kept in
marrow as memory cell ready for next
exposure to same antigen
Primary immune
response
The immune response of the body
when exposed to antigen for the
first time >> antibodies are formed
after a latent period (1-2 w), time
needed for multiplication and
maturation of lymphocytes
(vaccination)
Secondary immune
response
Upon the second exposure to the
same antigen.


immediate production of high titer
antibodies
Due to the presence of memory
lymphocytes (from first exposure)
which react immediately when
exposed to the same antigen
Cellular immunity
T-cell
react with antigen > proliferate to
give either:
Cytotoxic
T cells CD8 (Tc) destroy foreign
cell, removed by macrophage, monocytes,
neutrophils
Helper
T cell CD4 (Th) secret lymphokinese
to attract macrophages, stimulate B cell to secret
antibodies against target cells infected with
viruses
Helper T-cells
• Most abundant.
• Secrete Cytokines (Interleukins)
• Stimulation of growth and proliferation of
cytotoxic T cells and suppressor T cells.
• Stimulation of B cell growth and
differentiation. Activation of macrophage
system.
• Feedback stimulatory effect on helper T
cells themselves.
Cytotoxic T-cells
(Killer cells)
Bind with specific antigen
Secrete perforins (hole forming proteins)
Fluid flows into the cell
Cell swells and dissolves
Suppressor T-cells
•Suppress the function of Cytotoxic
and helper T cells.
•Helper and Suppressor T-cells are
called regulatory T-cells.
Function of Cellular immunity
1.
2.
3.
4.
Rejection of transplanted
tissues (kidney)
Delayed hypersensitivity
reaction (tuberculin)
Antitumor immunity
Cooperation with B cell in
humoral immunity
Clinical importance
The Acquired Immune Deficiency
Syndrome (AIDS)





AIDS virus selectively attack Th (CD4),
reversing Th:Tc ratio 1:2
Normal Th (CD4) : Tc (CD8) ratio 2:1
inhibition of immune response
prone to bacteria/ viruses infection
Cancer
Immunization
Active immunity:
•Dead organism.
•Toxins.
•Live attenuated organism.
Passive immunity:
Infusion of antibodies, activated T-cells or
both.
SUMMARY
Thank you