Dr. Walid Daoud, A. Professor Blood Week 9 Dr. Walid Daoud, A. Professor

White Blood Cells (Leukocytes) ____________________________ Total leukocytic count = 4,000-11,000/mm3 Classification: 1. Granular leukocytes: - Neutrophils. - Eosinophils. - Basophils. 2. Agranular leukocytes: - Monocytes. - Lymphocytes.

White Blood Cells (Leukocytes) ____________________________ Formation of Leukocytes (Leukopoiesis): All in bone marrow except lymphocytes in lymphoid tissues (LN, thymus & spleen). Pluripotent stem cells ↓ Colony forming unit-granulocyte-monocyte ↓ GM-CSF ↓ Myeloid line Lymphoid line - Granulocytes Lymphocytes - Monocytes

White Blood Cells (Leukocytes) ____________________________ Functions of Granular Leukocytes: 1-Neutrophils (60-70%): The 1st line of defense against organisms. a- Margination. b- Diapedesis. c- Amoeboid movement. d- Chemotaxis. e- Phagocytosis.

White Blood Cells (Leukocytes) ____________________________ 2- Eosinophils (2-6%): a- They kill parasites. b- They increase in allergic conditions. c- Weak phagocytosis and show chemotaxis 3- Basophils (0-1%): a- Contain histamine and heparin. b- Possess IgE receptors on their membranes

White Blood Cells (Leukocytes) ____________________________ Functions of Agranular Leukocytes: 1-Monocytes (2-8%): a- Become tissue macrophage (RES). b- Migration. c- Phagocytosis. 2-Lymphocytes (20-30%): Immune function.

Pathological Variation in Leukocytic Count ______________________________________ Leukopenia: Leukocytosis: -Chronic infection. -After meal, during -Drugs. Exercise and stress. -Starvation. -Inflam., M. infarction Agranulocytosis: -Exposure to gamma rays. -Drugs.

Immunity ____________________________ It is the ability of the body to resist almost all types of organisms and toxins. 1-Innate (non-specific) immunity: . Resistance of skin to invasion by organism. . Destruction of organism by gastric HCl. . Phagocytosis. 2-Acquired (specific) immunity: . Humoral immunity: B-lymphocytes. . Cellular immunity: T-lymphocytes.

Antigens ____________________________ They are substances that are able to induce an immune response & to react specifically with its products. They possess certain chemical structures specific to them known as antigenic determinants, molecular weight > 10,000. Antigenic determinants are present on cell membranes or free e.g., bacterial toxins.

Development of Immune System ____________________________ I-Origin of lymphocytes: In fetus, lymphocytic stem cells formed in bone marrow migrate either: . To thymus gland to give T-lymphocytes or . To bursa-equivalent tissues (liver & spleen) to give B-lymphocytes. II-Processing of lymphocytes: 1- Recognition. 2- Specification.

Development of Immune System ____________________________ III-Lymphocyte migration: They migrate to live in lymphoid tissues as lymph nodes, spleen, liver & bone marrow. Types of lymphocytes: 1- B-lymphocytes. 2- T-lymphocytes. 3- Non B non T-lymphocytes (NK cells)

Development of Immune System ____________________________ Varieties of B-lymphocytes: - Plasma cells. - Memory cells. Varieties of T-lymphocytes: - Cytotoxic (Killer) T-cells. - Helper T-cells. - Suppressor T-cells. - Memory T-cells.

Major Histocompatibility Complex (MHC) ___________________________________ It is a protein on cell membrane genetically encoded by chromosome 6. Two classes: . MHC class I protein: on all nucleated cells. . MHC class II protein: on antigen presenting cells, mostly macrophages. MHC proteins are specific for individual and distinguish self from non-self. Cellular immune response occurs when foreign antigen and MHC protein are coupled and presented together to the immune system.

Cellular Immunity ____________________________ -Done by activated cytotoxic T-lymphocytes. -It occurs on exposure to: .Viruses, fungi, few bacteria e.g. TB. .Cells from other individuals (tissue transplant) .Tumor cells. When cytotoxic T-cells are activated they proliferate and differentiate into clones of: 1-Activated cytotoxic T-cells. 2-Memory T-cells.

Humoral Immunity ____________________________ Produced by B-lymphocytes. Mainly acts against bacterial infections. Activated B-lymphocytes specific to antigen differentiate into: 1-Plasma cells. 2-Memory B-cells.

Mechanism of Action of Antibodies _______________________________ A. Direct attack of antigen: 1- Agglutination of bacteria. 2- Precipitation of antigen. 3- Lysis. 4- Opsonization. B. Activation of the complement system.

Nature and Structure of Antibodies _____________________________ Antibodies are γ globulins (immunoglobulins): IgG, IgM, IgA, IgE and IgD Antibody is formed of light and heavy polypeptide chains bound together by disulphide (S-S) bonds known as heavy-light chain pairs. Each pair is bound to another by interchain disulphide bridges.

Classes of Antibodies ____________________________ -Immunoglobulin G (IgG). -Immunoglobulin M (IgM). -Immunoglobulin A (IgA). -Immunoglobulin E (IgE).

Undesirable Consequences of Immune Response ____________________________ 1-Graft rejection. 2-Auto-immune diseases. 3-Acquired immune deficiency syndrome (AIDS)

Blood Groups ____________________________________________________________________________________________________________________________________________ ABO System: A and B antigens on red cell membrane (agglutinogen). Antibodies in plasma (agglutinins). According to presence or absence of A and B antigens, humans are divided into 4 blood groups: % Agglutinin Agglutinogen B. group 40% 10% 5% 45% anti B anti A - Anti A and anti B A B A and B AB O

Importance of Blood Groups ____________________________________________________________________________________________________________________________________________ 1-Medicolegal importance: Determination of blood group can confirm that a certain man is not the father of a specific child, but not that he is. That is a good negative. 2-Incompatible blood transfusion: Donor RBCs are agglutinated by recipient plasma but donor serum rarely agglutinate recipient RBCs. Therefore: Group O is a universal donor. Group AB is a universal recipient.

Blood Groups ______________________________________________________________________________________________________________________________ Rh System: Rh factor is agglutinogen on RBCs (D antigen) in 85% of white population (Rh-positive) while who do not have (Rh-negative). Antibody against Rh agglutinogen (anti D) normally not present in plasma and formed only when Rh-ve individual receives Rh+ve blood.

Importance of Rh Factor ______________________________________________________________________________________________________________________________ 1-Blood transfusion: If Rh-ve individual receives Rh+ve blood. 2-Erythroblastosis fetalis: When Rh-ve female marries Rh+ve male leading to kernicterus of fetus. Prevention: -Anti D antibodies given to mother after delivery to neutralize Rh antigen. -Rh-ve person should never receive Rh+ve bl.

Blood Transfusion ____________________________________________________________________________________________________________________________________________ Indications: 1-To restore blood volume as in hemorrhage 2-To restore certain blood elements: RBCs in anemia, WBCs in leukopenia, platelets in purpura, clotting factors in hemophilia, antibodies in infection, plasma proteins in hypoproteinemia. 3-In erythroblastosis fetalis. Dangers of incompatible blood transfusion.