White blood cells & Immunity (The Guyton and Hall Physiology)

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
GRANULOCYTES
Polymorphonuclear neutrophils 60-70%
Polymorphonuclear eosinophils 2-3%
Polymorphonuclear basophils 0.4%
NON-GRANULOCYTES
Monocytes 5.3%
Lymphocytes 30%

Granulocytes and monocytes are formed and stored only in bone marrow
Lymphocytes and plasma cells are formed and stored mainly in various lymphoid tissue such as lymph node, spleen, thymus and tonsils as well as in bone marrow.
GRANULOCYTES
4 to 8 hours in blood and 4 to 5 days in tissues
MONOCYTES
Monocytes also have a short transit time:
10 to 20 hours in blood and In tissue they swell to much larger size to become tissue macrophages.
LYMPHOCYTES
weeks to months
neutrophil
. 60-70% of leukocytes
nucleus: 2-5 lobes
Counting the number of lobes and grouping them is called Arneth count.
Shift to left means (increase no of young and predominant WBCs) e.g During acute infection.
Shift to right means, old cells are predominant. e.g During recovery phase
NEUTROPENIA
Decrease in neutrophils count
Typhoid
AIDS and viral hepatitis
Kalazar fever
Bone marrow depression by drugs and radiations
NEUTROPHILIA
Increase in neutrophils count
Appendicitis , Tonsillitis, Pneumonia
Burns, Hemorrhage, MI, Pain
Hypoxia, Pregnancy
BASOPHIL
Their cytoplasmic granules take up basic dyes and appear deep blue
MAST CELLS are derived from basophils under the influence of interleukins 3 and 4
Under many allergic conditions basophils and mast cells bursts and releases
Histamine
Bradykinin
Serotonin
Slow reacting substance of anaphylaxis
Heparin
Lysosomal enzymes
It is the capacity of the human body to resist and destroy the invading organisms or toxins.

1. WHITE BLOOD CELLS Maryam Fida (o-1827) Source: The  Guyton  and Hall Physiology

2. WHITE BLOOD CELLS (Leukocytes) 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

3. TYPES OF W.B.C GRANULOCYTES Polymorphonuclear neutrophils 60-70% Polymorphonuclear eosinophils 2-3% Polymorphonuclear basophils 0.4% NON-GRANULOCYTES Monocytes 5.3% Lymphocytes 30%

4. GENESIS OF W.B.C Granulocytes and monocytes are formed and stored only in bone marrow Lymphocytes and plasma cells are formed and stored mainly in various lymphoid tissue such as lymph node, spleen, thymus and tonsils as well as in bone marrow.

5. LIFE SPAN OF W.B.C. GRANULOCYTES 4 to 8 hours in blood and 4 to 5 days in tissues MONOCYTES Monocytes also have a short transit time: 10 to 20 hours in blood and In tissue they swell to much larger size to become tissue macrophages. LYMPHOCYTES weeks to months

6. GRANULOCYTES 1. NEUTROPHIL . 60-70% of leukocytes nucleus: 2-5 lobes Counting the number of lobes and grouping them is called Arneth count. Shift to left means (increase no of young and predominant WBCs) e.g During acute infection. Shift to right means, old cells are predominant. e.g During recovery phase NEUTROPENIA Decrease in neutrophils count Typhoid AIDS and viral hepatitis Kalazar fever Bone marrow depression by drugs and radiations NEUTROPHILIA Increase in neutrophils count Appendicitis , Tonsillitis, Pneumonia Burns, Hemorrhage, MI, Pain Hypoxia, Pregnancy 3 types of granules 1. Specific Most abundant . collagenase, phospholipase and Lysozymes 2.Azurophilic lysosomes 3.Tertiary Gelatinase , collagenase help in movement in connective tissue Function a. defense against bacterial infection b. amoeboid movement, margination, diapedesis, chemotaxis (C5a) and phagocytosis

7. 2. EOSINOPHIL Constitute about 2 -3%. Nucleus is bi-lobed giving appearance of spectacle. Acidophilic granules are present. Are weak phagocytes FUNCTIONS KILLING PARASITES a. Releasing hydrolytic enzymes b. Highly reactive form of oxygen c. Releasing major basic protein Eosinophilia Allergic conditions Parasitic infections Collagen vascular diseases e.g. rheumatoid arthritis Addison’s disease Drugs like aspirin, penicillin and streptomycin Eosinopenia Administration of glucocorticoids Over activity of adrenal cortex

8. Basophils Their cytoplasmic granules take up basic dyes and appear deep blue MAST CELLS are derived from basophils under the influence of interleukins 3 and 4 Under many allergic conditions basophils and mast cells bursts and releases Histamine Bradykinin Serotonin Slow reacting substance of anaphylaxis Heparin Lysosomal enzymes Basophilia occurs in: 1) Small pox 2) Chicken pox

9. AGRANULOCYTES MONOCYTES Agranulocytes Large mononuclear cell Kidney shaped or horse shoe shaped nucleus Originate in bone marrow Circulate in blood In connective tissue differentiate into macrophages Monocytosis occurs in: 1) tuberculosis 2) Syphilis 3) malaria 4) kala azar 5) Glandular fever LYMPHOCYTES Helps in immunity.

10. Immunity It is the capacity of the human body to resist and destroy the invading organisms or toxins.

11. Development of Lymphocytes Lymphocytes are the vital component of immune system which includes bone marrow, thymus, spleen, lymph nodes, tonsils, Peyer’s patches, appendix. Earliest ancesters first appear in the primitive yolk sac during the first trimester of pregnancy. Later during the second and third trimester these are found in the liver and spleen . The PHSC give rise to CFU & LSC . The LSC give rise to lymphoblasts & then to lymphocytes . The lymphocytes designate to develop cellular immunity migrate into thymus gland and are transformed into T-lymphocytes. The lymphocytes designate to develop humoral immunity are processed in liver during fetal life and bone marrow after birth and are transformed into B lymphocytes.

12. T lymphocytes Types of T lymphocytes: Cytotoxic or killer kill bacteria or organism by CD8 By producing a protein perforin, it produces perforation in bacterial cells. 2) Helper T 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 They are damaged by AIDS virus results in AIDS. 3) Suppressor or regulatory Regulate the function of helper and killer T cells. These help in immune tolerance for bodies own cells. 4) Memory T cells When the body is exposed to to the same antigen second time, the memory cells identify the organisms and immediately activate the other T cells. So, the invading organism is destroyed very quickly. B lymphocytes Activation of B lymphocytes, Proliferation of plasma cells, production of more amount of antibodies by 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

13. Types of Immunity 1. Innate immunity: This type involves general and not specific processes, such as: i ) phagocytosis of bacteria by phagocytes of the blood and tissues ii) certain enzymes ( e.g.lysozymes ) that can destroy bacteria non-specifically. Acquired immunity Depends on the presence of specific proteins called antibodies. It is sub-classified into two types: a) Passive b) Active. A) Passive immunity: It is produced by administration of already made antibodies, e.g., serum obtained from actively immunized horses or human serum rich in antibodies against invading bacteria, viruses. B) Active immunity: This type of immunity results when the body of a human being itself produces an immune reaction in response to the entry of antigen into the body.

14. Active Immunity It is of two types: i ) Humoral Immunity: Plasma cells derived from B lymphocytes (interleukins derived from T cells and monocytes stimulate transformation of B cells into antibody-forming plasma cells) Plasma cells manufacture gamma globulins which are called as (Immunoglobulins). They enter the plasma and referred as humoral antibodies. Cell-mediated immunity: There is formation of activated or sensitized T lymphocytes that are specially designed to destroy the foreign agent (antigen) against which these cells have been activated. Both T and B lymphocytes affects the activity of each other.

15. Humoral Immunity Is by antibodies (gamma globulins) produced by the plasma cells. It is the major defensive mechanism against the bacterial infection. When antigen presenting cells present the antigen to B lymphocytes along with HLA , they activate the B cells and also helper T cells. B cells proliferate and transformed into plasma cells and memory cells. The plasma cells produce the antibodies: Which are globulin in nature. (about 2000 mol. of antibodies per second produced by plasma cell). Types: IgA, IgD, IgE, IgG, IgM.

16. Humoral Immunity The molecule of an immunoglobulin consists of a portion which binds to the polymorphonuclear leucocytes or macrophages and another portion which binds specifically with the antigen that produced the specific antibodies. If the same antigen gets into the body again, a specific antigen-antibody reaction is produced. IgG is the major component in most antibody responses.

17. IgM is often the first antibody to appear on entry of the bacteria or viral antigens. IgA is especially prominent in GIT and respiratory tract and IgE is important in certain allergic diseases. Function of IgD is unknown. Both IgG and IgM are opsonins.

18. Monocytes-Macrophages cell system(Reticuloendothelial system) 1. First line of defense With in minutes Fixed tissue macrophages Tissue macrophages in liver = kupffer cells Tissue macrophage in skin = Histiocytes Tissue macrophage in brain = Microglia . Second line of defense with in 1st hour or so Neutrophils 3. Third line of defense several days Invasion of monocytes and then in tissues becoming macrophages 4 . Fourth line of defense takes 3 to 4 days Increased production of granulocytes and monocytes in bone marrow

19. LEUKEMIAS Uncontrolled production of W.B.C . LEUKOCYTOSIS Controlled production of WBC LEUKOPENIA Bone marrow produces very few or stop producing W.B.C CAUSES Aplasia of bone marrow caused by Irradiation Certain drugs like benzene, chloramphenicol Direct action: A) Include precipitation B) Agglutination C) Neutrilization D) Lysis 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