This document summarizes the different types of white blood cells (leukocytes), including granulocytes and agranulocytes. Granulocytes include neutrophils, eosinophils, and basophils which have lobed nuclei and granules. Agranulocytes are lymphocytes and monocytes which have round nuclei and no granules. The document describes the structure, function, and role of each type of white blood cell in the immune system.
5. WHITE BLOOD CELLS
• Leukocytes or WBCs are the mobile units
of the body’s immune defense system.
• Immunity is the body’s ability to resist or
eliminate potentially harmful foreign
materials or abnormal cells.
• WBC count: 5000 to 11000/ul of blood
6. • Leukocytosis:
• occurs in:
• a) Infections
• b) Allergy
• c) Common cold
• d) Tuberculosis
• e) Glandular fever
7. White Blood Cells
• Classified as Granulocytes and Agranulocytes.
• Life of granulocytes:
• 4 to 8 hours in the blood
• 4 to 5 days in tissues
• Monocytes also have a short transit time:
• 10 to 20 hours in the blood.
• In tissue they swell to much larger size to become tissue macrophages.
• Lymphocytes have a life spans of weeks or months.
• Platelets are replaced about once every 10 days, about 30,000 platelets
are formed each day/ul of blood.
9. Formation of Leucocytes
• In the embryo:
• WBCs develop in the mesoderm and migrate into the blood vessels.
• At the 3rd month of intrauterine life:
• Lymphopoiesis first appears in the liver and thymus.
• In last trimester:
• Bone marrow forms stem cells. Some of which migrate to the thymus where T
lymphocytes take origin.
• At birth, the thymus weighs 10 to 12 g and cell mediated immunity well developed so
that graft rejection can occur.
• In the extrauterine life the granulocytes exclusively develop in the red bone
marrow.
• Lymphocytes and monocytes, also develop from stem cells in the bone
marrow.
10. Granulopoiesis
• Haemocytoblast
• ↓
• Myeloblasts (18um), large nucleus, several nucleoli
• ↓
• Promyelocyte (have reniform nuclei, multiple nucleoli, a few granules)
• ↓
• Myelocytes (3 types: neutrophilic, eosinophilic and basophilic) depending upon the
staining characters of their granules. Cytoplasm is more extensive, and nuclei are
smaller and there are no nucleoli.
• The cells are in the bone marrow.
• ↓
• Metamyelocytes
• ↓
• Neutrophils, eosinophils and basophils
• The complete maturation process from myeloblasts to neutrophils takes about 3
days.
13. • The signs of maturation:
• A) Cell and nucleus size becomes smaller
• B) Cytoplasm becomes less basophilic except in
plasma cell
• C) Granules appear with characteristic staining
characters.
14. Neutrophils
• Size: 10-14 µ. The neutrophils show amoeboid movements and
these cells do not divide.
• Cytoplasm contain granules. Neurophils are rich in lysosomal
enzymes.
• Neutrophils have a short stay in the circulation; after migration to the
tissue, they never return to the blood stream. Survival time is 9 days.
• Stained by acidic and basic dyes.
• Nucleus is multilobed, number of lobes varies b/w 1-5.
• Aged cells have more lobes.
• 50-70% of all leucocytes
17. 5. azurophilic granules
a. lysosomes
6. life span 1-4 days in
Connective tissue.
7. function
a. defense against
bacterial infection
b. diapedesis,
phagocytosis
18. • Neutrophils are called microphages.
• Counting the number of lobes and grouping them is called Arneth
count.
• Shift to left means (increase no of young and predominant WBCs).
• Shift to right means, old cells are predominant.
• During acute infection there is shift to left.
• Recovery Phase:
• Shift to right.
• Their reaction ranges from mild allergy → anaphylactic shock.
19. • Neutrophilia:
• Increase in Neutrophil count.
• Occurs in:
• 1) Acute bacterial infections maintains increased neutrophil production in
the bone marrow.
• 2) metabolic disorders
• 3) injections of foreign proteins
• 4) poisoning by chemicals and drugs like lead,
• mercury
• 5) poisoning by insect venom
• 6) after acute hemorrhage
• 7) ACTH of the anterior pituitary glands and cortisol of the adrenal cortex
• 8) adrenaline and exercise
20.
21. Development
• Originate from pleuripotent stem cells and become Comitted stem
cells (for ganulocyte & monocyte) CFUGM
• ↓
• Myeloblast (large cell with nucleus)
• ↓
• Promyelocyte
• ↓
• Myelocyte (megamyelocyte)
• ↓
• Metamyelocyte
• ↓
• juvenile or band stage
• ↓
• Mature
22.
23. Properties of Neutrophils
• 1) Amoeboid movement:
• Remain in circulation for 4-8hrs & then passed
to the tissues, they show amoeboid movement.
• 2) Margination and diapedesis:
• They show margination & diapedesis, lined up
along capillary wall (margination).
• 3) Squeeze through pores b/w adjacent
endothelial cells.
24. • 4) They show chemotaxis (move towards the source of chemotactic
factors).
• Chemotactic factors include bacterial toxins & degenerative products
from inflammed tissues.
• C5a is very important chemotatic factor.
• They reach at the site of infection & phagocytose the organisms.
• It can phagocytoze 3 to 20 bacteria.
• After that they die and called pus cells.
Granules contain myeloperoxidase, defensin, elastases.
• Pyrogens: are released by neutrophils and cause fever.
25. Causes of Phagocytosis
• Abnormal rough surface.
• Abnormal charge on the surface of organism.
• Opsonization:
• When microorganism enter the body, immune system produce antibodies
called opsonins like IgG. It coats the surface of bacteria, so that they
become tasty to be engulfed.
• Before ingestion, certain bactericidal substances are produced by
neutrophils i.e; myeloperoxidase and these first kill bacteria to make their
ingestion easy i.e; superoxide, hydro-oxyl ions, hydrogen peroxide &
hydrochlorate (HOCL3).
• Respiratory burst is by enzyme- NADPH oxide, Superoxide Dismutase,
Catalase.
26. Eosinophils
• Normal Size:10-14 µ size
• Constitute about 2%.
• Nucleus is bi-lobed giving appearance of spectacle.
• In cytoplasm:
• Acidophilic granules are present.
• Are weak phagocytes.
27. Eosinophils
1. 2-4% of leukocytes
2. 12-15 mm diameter
3. bilobed nucleus
4. ~200 eosinophilic
granules
28. • They have high peroxidase content which
accounts for their parasiticidal action.
• Collects around site of allergic reactions and are
increased in infestation of the body by parasites
and in skin diseases.
• They release Major basic protein (MBP) which
have bactericidal action.
29. Eosinophils
• They help to detoxify the products of allergic reaction by
removing histamine, bradykinin & serotonin.
• They release hydrolytic enzymes from their granules,
which are modified lysosomes.
• They release highly reactive form of oxygen that are
lethal to paracites.
• They kill by releasing larvacidal polypeptide called major
basic protein.
30. Eosinophils
4. ~200 eosinophilic
granules (12.5,12.8)
5. antiparasitic &
modulate inflammation
Note: staining of rbc’s
indicates acid stain color,
which may vary considerably.
Giemsa stain.
31. • Engulf antigen-Antibody (Ab) complexes, when they have initiated
the immune response.
• Migrate to the areas of inflammation during resolution and remove
tissue debris. So help in tissue resolution.
• Contain Pro-fibrinolysin activated to fibrinolysin, which dissolute the
blood clots.
• Eosinophils migrate into blood clots & help dissolving them.
• Eosinopenia is produced by cortisol and ACTH as happens under
stressful conditions.
33. Basophils
• Are the smallest of the WBCs.
• Percentage in blood is (0.4-1.1%).
• Normal Size: 10 µ.
• Large nucleus present.
• Darkely stained granules in cytoplasm, which are so darkely stained that
they even masked nucleus (basophilic stain).
• Granules contain histamine, bradykinin, Heparin (natural anticoagulant),
serotonin.
• In the tissues, large cells are present called mast cells, which are
functionally related to basophils.
34. Basophils
• On the membranes of basophils and mast cells, receptor
for IgE antibodies are present.
• When the antigen to which person is sensitive enters the
body Ag-Ab reaction happens on the surface of Mast
cells and Basophils and cause rupture of these cells.
• Histamine and other substances are released and
allergic reaction is produced.
•
• Heparin is released.
35. Basophils
1. < 1% of leukocytes
2. 12-15 mm diam.
3. 0.5 mm
diam.basophilic granules
36. • Mast Cells:
Mast cell is a large tissue cell resembling the basophil.
• It is present in bone marrow and around the cutaneous
blood vessels but does not enter the blood circulation.
• The mast cell plays an important role in producing the
hypersensitivity reactions like allergy and anaphylaxis.
• It secretes histamine, serotonin and hydrolytic enzymes.
37. • Basophilia occurs in:
• 1) Small pox
• 2) Chicken pox
• 3) polycythemia vera
38. • Leucopenia:
• The decrease in the total white blood cell count occurs in
the following pathological conditions:
• 1. Anaphylactic shock
• 2. Cirrhosis of liver
• 3. Disorders of spleen
• 4. Pernicious anemia
• 5. Typhoid and paratyphoid fever
• 6. Viral infections
39. • Leucocytosis:
• Occurs in the common pathological conditions
like:
• 1. infections
• 2. Allergy
• 3. Common cold
• 4. Tuberculosis
• 5. Glandular fever
40.
41. Monocyte
• Largest WBCs, size: 16-18 µm.
• Have single kidney shaped indented nucleus at
periphery.
• Cytoplasm is without visible granules.
• Remain in circulation for 72 hrs, then migrate into tissue,
where enlarge to form tissue macrophages.
• Life span: 72 hrs in circulation, 3 months in tissues.
• Macrophages can be mobile or fixed.
42. Monocytes
1. 12-20 mm diameter
2. nucleus: oval,
horseshoe/kidney
shaped, eccentric
3. become wandering
macrophages after
diapedesis
43. Monocytes
• Fixed phagocytic cells:
• Present in the different parts of reticuloendothelial cells
i.e; Kuffer cells in liver, in alveoli→ alveolar
macrophages.
• In Bone marrow & lymph nodes & in pulp of spleen and
in skin histiocytes.
• All of these are derived from monocytes.
• Osteoclasts also develop from monocyte series and
causes bone resorption.
44. • Formation of monocytes:
• monocytes are also developed from bone
marrow.
• The stem cell is colony forming unit-
Granulocyte-Monocytes (CFU-GM) that
develops into myeloblast.
• The myeloblast is converted into monoblast,
which develops into monocyte.
46. Functions
• Phagocytic activity is shown in tissues only but not much
in blood.
• Macrophage can phagocytize upto 100 bacteria, also
engulf dead neutrophil. Macrophage can ingest old
RBCs and large organisms.
• Monocytes show margination, diapedesis and
chemotaxis.
• When these engulf bacteria, it is broken, antigen is
isolated, processed and then presented to immune
system to initiate the immune reaction.
47.
48. Lymphocytes (Agranulocytes)
• Depending upon size, they are large or small.
• Percentage in blood: 25-40%.
• There are two types according to function.
• 1) T lymphocytes: Thymus dependent
• 2) B lymphocytes: bursa dependent.
49. Formation of Lymphocytes
• The formation of lymphocytes are in the bone
marrow.
• The PSC gives origin to colony forming units
(CFU) and lymphoid stem cells (LSC).
• The lymphoid stem cells give origin to
lymphoblasts, which develop into lymphocytes.
• These lymphocytes are released from the bone
marrow into the circulation.
50. • Some of the lymphocytes enter the thymus.
• In thymus, these lymphocytes are processed
and come out of thymus as T lymphocytes.
• The remaining cells enter liver and bone marrow
and are processed as B lymphocytes.
51. • In human beings, bone marrow or liver correspond to
bursa of fabricus.
• During fetal life, T and B lymphocytes originate from
common stem cells.
• T lymphocytes:
T cells migrate from bone marrow to thymus where it
proliferate to form T lymphocyte
• Processing occur in fetal life and some period after birth.
53. • Leukemia:
• It is associated with abnormal and uncontrolled increase
in total white blood cell count It is a cancer of blood. The
abnormal of leucocytes is reduced on X-rays exposure
and treatment with antileukaemic drugs.
• Agranulocytosis:
• There is marked reduction in the number of granulocytes
and these persons are highly susceptible to bacterial
infections.
54. B Lymphocytes
• Other cells migrate to fetal bone marrow or fetal liver, processed and form B
lymphocytes.
• Then migrate to lymphoid tissue and proliferate to form more and more B
lymphocytes.
• T lymphocytes:
• Are involved in cell mediated immunity and tissue graft reaction.
• B lymphocytes:
• Are involved in humoral immunity.
• Types of T lymphocytes:
• 1) Cytotoxic or killer
• 2) Helper
• 3) Suppressor or regulatory
• 4) Memory T cells
55. Helper cells
• Produce lymphokines or cytokines CD4, which
regulate many aspects of immune system.
• 1) helps macrophage in antigen processing.
• 2) regulate function of B-lymphocytes
• 3) regulate killer cells
• 4) regulate suppressor cells
• All the above functions are performed with the help of
cytokines.
• They are damaged by AIDS virus results in AIDS.
56. Cytotoxic and Suppressor cells
• Cytotoxic cells:
• kill bacteria or organism by CD8.
• By producing a protein perforin, it
produces perforation in bacterial cells.
• Suppressor cells:
• Regulate the function of helper and killer T
cells. These help in immune tolerance for
bodies own cells.
57. B Lymphocytes
• Are involved in humoral immunity.
• When antigen activates the B lymphocytes, there is formation of
Plasma blast→ Plasma cells, which have got highly developed
endoplasmic reticulum.
• Five types of Immunoglobulins:
• IgA, IgE, IgM, IgD, IgG (IgM is formed first on the exposure of
antigen and than IgG are formed)
• 75% is IgG.
• Antibodies act on antigens directly or indirectly.
58. • Direct action:
• A) Include precipitation
• B) Agglutination
• C) Neutrilization
• D) Lysis
59. • Indirect action:
• Is through activation of complement system
• Inactive proteins present in body fluid, activated
in a cascade manner.
• C4a, 3a, 5a activate mast cells and basophils.
• C3b causes opsonization.
• C5a is powerful chemotatic agent.
60. • C5b6789 cause lyses of cells.
• Antibodies are immunoglobulin (Ig), molecular wt. is variable.
• Each Immunoglobulin (Ig) has a polypeptide chain (2 heavy + 2 light
chains).
• They have constant and variable portion.
• Constant is same in all Igs, but variable is different and specific for
different antibodies and have sites for antigen binding.
• When B Lymphocytes are exposed to antigens, memory B cells are
formed.