WBC (White blood cell)

According to presence or absence of granules in

cytoplasm WBC can classify into:

W.B.C

• Granulocytes • Agranulocytes

I) Neutrophil I) Monocytes

II) Eosinophil Large

III) Basophil II) Lymphocyte

Small
i) B lymphocyte

ii) T lymphocyte

o Helper T cell

o Suppressor Cell

o Cytotoxic T Cell
Granulocytes:
1) Neutrophil
2) Eosinophil
3) Basophil
Agranulocytes:
1) Monocytes
2) Lymphocytes
According to size:
I) Large II) Small
According to site of synthesis:
1) B Lymphocyte
ii) T Lymphocytes
• Helper T cell
• Supressor T cell
• Cytotoxic T cell

T.C of WBC (Total count):

Total number of WBC per Cu mm of blood.
Average 7000/Cu mm of blood.
Range: 4000-11000 / Cu mm of blood.

D.C of WBC (Differential count of W.B.C):

Number of each varieties of W.B.C in 100
W.B.C

• Neutrophils—(50%-70%)
Average: 60%

• Eosinophils—(1%-4%)
• Basophils- (0-1%)
• Lymphocytes- (20%-40%)
• Monocytes-(2%-8%)
Absolute Count (AC) of W.B.C:
Number of each varieties of WBC per Cu mm
of blood.

• Neutrophils- 3000-6000/ Cu mm of blood

• Eosinophils- 150-300/ Cu mm of blood
• Basophils- 0-100/ Cu mm of blood
• Lymphocytes- 1500-2700/ Cu mm of blood
• Monocyte- 300-600/ Cu mm of blood
Morphology of different W.B.C:
A. Granulocytes ( Polymorpho nuclear)
1. Neutrophil
• Cell size- 10-14 micro m
• Nucleus- 2-5 lobes
• Granules stain- violet or red brown
granules
• Granules: Fine granules.
2. Eosinophil
• Cell size-10-14 µm
• Nucleus- Bilobes
• Granules Stain- Reddish granules in

cytoplasm, Larger than Nutrophil

granules.

3. Basophil
• Cell size-10-14 µm
• Nucleus-Bilobes
• Granules Stain- Purple blue granules
overlapping the Nucleus
• Coarser than eosinophil granules.
B) Agranulocytes:
1) Lymphocytes
• Cell size
• Large- 10-14 µm
• Small- 7-10 µm
Granules- absent
Nucleus- rounded
Rim of cytoplasm around the nucleus

2) Monocyte-
• Cell size- 10-18 µm
• Nucleus kidney shaped (horse shoe shape)
• Granules- Absent

Functions of W.B.C-
1. Defensive function
a) Phagocytic function-
Neutrophil
Macrophage
b) Antibody formation- B lymphocyte
converted into plasma cell and plasma
cell helps antibody formation.

2. Basophil:
 Secrets Heparin, histamine,
bradykinin, serotonin, eosinophil
chemotactic factor, slow reactive
substance.

3. Eosinophil
a) Attach to the juvenile form of parasite
and kill some of them. Trichinella,
microfilaria, Schistosoma.
Kill the parasite by-
I. Releasing hydrolytic enzymes
II. MBP( Major basic protein)
III. Highly reactive oxygen (o2-,H202,OH-)

b) Detoxify the inflammation including

substances, release from mast cell and
basophil. Probably also pagocytosis
c) Destroy allergen antibody complex.
 4. T Lymphocytes

Helper T-
a) Stimulation of growth and
proliferation of cytotoxic and
suppressor T cell.
b) Stimulation of B cell growth and
differentiation of plasma cell and
antibodies formation.
c) Activation of the Macrophage system.
d) Feedback stimulatory effect on the
helper T cell.

Supressor T cell:
Supressing the cytotoxic and helper T cell.
Cytotoxic T cell:
Killing the micro-organism.

Properties of WBC:
• Diapedesis:
Neutrophil and Monocytes can squeeze
through the pores of the blood capillaries by the
process of Diapedesis.

• Ameboid movement:
❖ Movement begins with protrusion of a
pseudopodium from one end of the cell.

❖ The pseudopodium projects far away

from the cell body
 ❖ Then attached to the new tissue area
and finally the remainder portion of the
cell moves towards the pseudopodium.

Chemotaxis: Many different chemical

substances in the tissue cause both neutrophil
and macrophage to move towards the source of
the chemicals. This
phenomenon is known as chemotaxis.
 These includes:(chemical substances)
I. Some of the bacterial toxins.
II. Degenerative products of the inflamed tissue
III. Several reaction products of the
“Complement complex”(C5a)
IV. Several reaction products caused by plasma
clotting in the inflamed tissue.
V. Leukotrines and polypeptides from
lymphocytes, mast cell and basophil.

Opsonization:
The process by which foreign
substance prepared for phagocytosis.

Opsonins:
❖ Ig G
❖ C3b
 Phagocytosis:
Cellular ingestion of the
offending agents.

Selective criteria for phagocytosis:

❖ Surface of the particle is rough
❖ No protective coat
❖ Recognizing certain foreign materials.

Steps of phagocytosis:
❖ Recognition and attachment of the
particle
❖ Engulfment
❖ Phagosome
❖ Digestive vesicle.
Mechanism of phagocytosis:
 Neutrophil and Monocyte engulf by
pseudopodia
↓
Phagosomes
↓
To form digestive vesicles
↓
Killing and digest micro organism

Killing agents:
Superoxide (0-2)
H202, 0H-
HoCl, HoBr, HoCN, HoI
 Activation of NADPH
oxidase(cell membrane bound
enzyme)

❖ Activation of NADPH oxidase

with increase O2 uptake and
metabolism in neutrophil- ie
glycogenolysis, glycolysis.
❖ (respiratory burst) makes toxic
oxygen metabolites
❖ Toxic metabolites with
proteolytic enzymes from
granules-(effective killing
machine in neutrophil)

202 +NADPH+H+ →NADP+ 2H+ +20-2

↑
SOD(SUPEROXIDE
DISMUTASE)
20-2 + 2H+→ H202 + 02
H202 + Cl-→H0Cl
↑
myeloperoxidase
 Reticuloendothelial(Monocyte-
Macrophage system):
Macrophages are one of the
components of mononuclear
phagocytic system.
• Diameter: 10-30 µm
Nucleus: Oval or kidney shape
Origin: Macrophage arises from
blood monocytes.
Function:
1) Phagocytosis: it
phagocytose micro organisms,
damaged and dead cells,
 cellular debris and then digest
the ingested material.

Killing agents:
Superoxide (0-2)
H202, 0H-
HoCl, HoBr, HoCN, HoI

Fixed tissue macrophages:

• Macrophage in the skin and
subcutaneous tissue named
Histocytes.
• Macrophage in the lymph nodes.
• Alveolar Macrophage in the
Lungs.
• Macrophages(Kupffer cells) in the
liver sinusoids.
• Macrophages in the spleen and
bone marrow.

Interpretation of TC of WBC:
Leucocytosis: Increase number of
leucocytes above upper normal
limit.
Cause:
a. Acute pyogenic infection
Acute appendicitis
 Acute tonsillitis
Acute pylonephritis
Acute Meningitis
b. Chronic Myeloid Leukemia

Leucopenia: Decrease total

Leucocyte count. Below lower
normal limit.

Causes:
a. Viral infection: influenza,
Infective Hepatitis
b. Bacterial infection: Enteric
fever
 c. Protozoal infection: cronic
malaria,Kala- azar
d. Aplastic anaemia.

Interpretation of D.C and A.C of

WBC:

Neutrophilia: Increase number of

neutrophil above upper normal
limit. Cause as leukocytosis

Neutropenia:
Decrease number of neutrophil
below lower normal limit.
Eosinophilia: Increase number of
Eosinophil above upper normal
limit.

Cause:
1. Helminthic infestation.(Filariasis,
Intestinal worm)
2. Tropical Eosinophilia
3. Allergic disorders like
asthma,Hay fever
4. Pulmonary eosinophilia.
Eosinopenia: Decrease number of
Eosinophil below lower normal
limit.

Lymphocytosis: Increase number of

Lymphocyte above upper normal
limit.

Cause:
1. Protozoal- chronic malaria,
cronic Kala-Azar
2. Viral disease- Infectious
mononucleosis
3. Bacterial- Tuberculosis
4. chronic Lymphatic Leukaemia.
Leukemia: Uncontrolled production
of White blood cells can be caused
by cancerous mutation of a
myelogenous or lymphogenous cell.

Granulopoisis: Development and

maturation of granulocyte.

Steps: pluripotent haemocytoblast

↓
Unipotent commited precursor stem cell
↓
Myeloblast
↓
Promylocyte(granules appears)
↓
Myelocyte
↓
Metamyelocyte
↓
Neutrophil,Eosinophil,Basophil

Pluripotent haemocytoblast
↓ ↓
Lymphoblast Unipotent
↓ ↓
Lymphocyte Monoblast
i) B ↓
ii) T Monocyte
 IMMUNITY
Immunity:
Immunity may be defined as the
ability of the body to recognize,
destroy, and eliminate antigenic
material foreign to its own.
 Immunity

non
specific(acquired)
specific(innate)

cell mediated
Humoral
T cell B cell

Innate Immunity:
This type of
immunity results from general
processes rather than from
processes directed at specific
disease organism.
 It includes:
I. Phagocytosis of bacteria and
other invaders by WBC and cells
of tissue macrophage system.
II. Destruction of swallowed
organisms by acid secretion of
the stomach and digestive
enzymes.
III. Resistance of the skin to
invasion by organisms.
IV. Presence in the blood of certain
chemical compounds that
attach to foreign organisms or
toxins and destroy them.
 These components are:
I. Lysozyme
II. Basic polypeptides
III. The complement complex
IV. Natural killer lymphocytes

Acquired Immunity:
Immunity is
caused by special immune system
that form antibodies, activates
lymphocytes that attacks and
destroy Specific organism and
toxins. It is two types:
I. Cell mediated Immunity: by
Helper T cell, and Cytotoxic T
cell.
In this type of immunity the body
formation of large number of
activated lymphocytes that are
specifically designed to destroy
the foreign agents. This type of
immunity is called cell mediated
or T cell immunity.
II. Humoral or antibody mediated
Immunity:
In this type of immunity the
body develops circulatory
antibodies, which are globulin
molecules that are capable of
attacking the invading agents.
This type of immunity is called
humoral immunity or B cell
immunity.
By B lymphocyte.

Difference between Innate and

acquired Immunity:
Innate Acquired
Immunity Immunity
 1. It is not 1. Specific
specific, and
Natural Acquired.
2. Not 2.Dependent
depended
on antibody
and T cell.
3.No memory 3.memory cell
cell. present.

Antigen: these are foreign

substances which are protein or
large polysaccharides in nature
and they initiates the acquired
immunity.These substances are
called antigen.

Antibody: an antibody is a type of

globulin produced in response to
an antigen with which it reacts
specifically.
Function of antibody:
1. By direct attack on the invader
2. By activation of complement
system.
Autoimmunity: is a state in which
the self tolerance is terminated as
a result antibody reacts upon own
cell.

Tolerance: may be defined as a

state in where the natural
unresponsiveness of the immune
system against an antigen.