overview of immunology 2024.pdf

OVERVIEW OF THE IMMUNE SYSTEM Dr. Tarfa Altorki Forensic Biology MLTF 601 2024 ✖ Class policies ✖ Mobiles are not allowed to be used in class and should be on silent mode.  History Concept of immunology Types of immunity Innate and adaptive Immunity...

OVERVIEW OF THE IMMUNE SYSTEM Dr. Tarfa Altorki Forensic Biology MLTF 601 2024 ✖ Class policies ✖ Mobiles are not allowed to be used in class and should be on silent mode.  History Concept of immunology Types of immunity Innate and adaptive Immunity Key terminology in immunology  History Milestones in the history of immunology include: 1798 Edward Jenner initiates smallpox vaccination. 1877 Paul Erlich recognizes mast cells. 1879 Louis Pasteur develops an attenuated chicken cholera vaccine. 1883 Elie Metchnikoff develops cellular theory of vaccination. 1885 Louis Pasteur develops rabies vaccine. 1891 Robert Koch explored delayed type hypersensitivity. 1900 Paul Erlich theorizes specific antibody formation. 1906 Clemens von Pirquet coined the word allergy. 1938 John Marrack formulates antigen-antibody binding hypothesis. 1942 Jules Freund and Katherine McDermott research adjuvants. 1949 Macfarlane Burnet & Frank Fenner formulate immunological tolerance hypothesis. 1959 Niels Jerne, David Talmage, Macfarlane Burnet develop clonal selection theory. 1957 Alick Isaacs & Jean Lindemann discover interferon (cytokine). 1962 Rodney Porter and team discovery the structure of antibodies. 1962 Jaques Miller and team discover thymus involvement in cellular immunity. 1962 Noel Warner and team distinguish between cellular and humoral immune responses. 1968 Anthony Davis and team discover T cell and B cell cooperation in immune response. 1974 Rolf Zinkernagel and Peter Doherty explore major histocompatibility complexrestriction. 1985 Susumu Tonegawa, Leroy Hood, and team identify immunoglobulin genes. 1987 Leroy Hood and team identify genes for the T cell receptor. 1985 Scientists begin the rapid identification of genes for immune cells that continues to the present.  Edward Jenner “the founder of modern Immunology” 1796-introduction of protective vaccine against small pox based on cow pox. Metchinkoff (1880) Cell based Immunity Merrill Chase (1940) Transfer of WBC (immunity to tuberculosis)  Immunity ?? The Latin term immunis, meaning “exempt,” gave rise to the English word immunity : (state of protection from infectious diseases). Immunity is body's ability to resist or eliminate potentially harmful foreign materials or abnormal cells.  The Human Body we are made up of warm, moist, nutrient rich substances, an ideal environment for the housing of microorganisms every drop of water we drink contains 100’s of bacteria the air we breath introduces millions of bacteria daily to our lungs every time we brush our teeth we drive microorganisms into our gums Bacteria on just brushed teeth Terminology Immunology The study of the immune system, a system that is responsible for the recognition and disposal of foreign (non-self) material. The immune system The immune system consist of proteins, cells, and organs that are responsible for the protection of an individual against threat of diseases caused by infectious organisms. Terminology Immune response Broad range of defense mechanisms including phagocytosis, inflammation and antibody synthesis, etc. Susceptibility: Lack of resistance to a disease. Immunity: Ability to ward off disease. Infectious organism= pathogen The individual(human or animal)= host The Invaders(pathogens) A pathogen or infectious agent is a biological agent that causes disease or illness to its host. The complexity of the immune system The desirability of eliminating a pathogen without causing damage to the host” Recognition “ Pathogens variability Size, shape, life cycle  Response to infection Awareness Recognition Immediate response Innate immunity Delayed response Adaptive immunity Destruction or Eradiation of elimination infection Immunity Generating memory to infection The immune system A functional system – NOT an organ system: Complex system – includes Skin – physical barrier Lining of mucus membranes – physical barrier Secretions – tears, mucus etc - antimicrobial Blood cells– WBCs Bone marrow Liver – makes complement proteins Lymphatic system and lymphoid organs Most tissues – have resident immune cells  Types of Immunity Immune System Innate Adaptive (Nonspecific) (Specific) Interactions between the two systems The Concept of Immunity Susceptibility: Lack of resistance to a disease. Immunity: Ability to ward off disease. Innate immunity: Defenses against any pathogen. Adaptive immunity: Immunity, resistance to a specific pathogen. Not discusses in this lecture Major Characteristics of the innate Immunity Non-specific Immediate response First line of defense Physical barrier Humeral and cellular Innate immunity Characteristics 1. present at birth 2. Can rapidly brought into action 3. Do not always have power to eliminate the infection. 4. Do not lead to long-term immunity to the particular pathogen (do not develop memory).  First Line of Defense: Skin and Mucous Membranes Physical Factors Epidermis: consists of tightly packed cells with keratin, a protective protein Two other protective physical factors of skin Mucus of mucous membranes Saliva Nose hairs  Anatomical Barriers – Chemical factors Lysozyme in tears / Antimicrobial HCl in saliva Peptides in sweat stomach  Anatomical Barriers – Biological factors Normal flora – microbes in many parts of the body Normal flora – > 1000 species of bacteria Normal flora – competes with pathogens for nutrients and space Innate immune system: components of Blood Complement proteins Coagulation proteins Extracellular Cytokines WBCs Complement System Summary Series of ∼ 30 plasma (serum) proteins, activated in a cascade Three effects of complement system: 1. Enhances inflammatory response, Increases phagocytosis Cytokines Small proteins – secreted by cells of the immune system Affect the behaviour of other cells signalling molecules Key players in innate and acquired immunity  White blood cells (WBCs) Macrophages Dendritic cell Eosinophil Monocyte B-lymphocytes T-lymphocytes lymphocyte Neutrophil Basophil Mast cells Cells of the innate immune system Major Characteristics of the Adaptive Immune Response Delayed response Specific Discrimination between self and non-self Memory Humeral and cellular Adaptive immunity Organs of the immune system Primary lymphoid organs Bone marrow and thymus Maturation site Secondary lymphoid organs Spleen, lymph nodes MALT(mucosal associated lymph tissue Effector site  Immunology Buzzword Pathogen= microorganism that can cause disease Antigen(Ag) = molecule that stimulate the immune system and is capable of binding T cell receptor or an Ab. Antibody(Ab)= a protein that recognizes a specific epitope of an Ag and facilitate the clearance of Ags. Immunoglobulin(Ig)  What are the functions of the immune system? 1. Defense 2. Removal of 'worn-out' cells 3. Identification & destruction of abnormal or mutant cells (1ry defense against cancer) 4. Rejection of 'foreign' cells (e.g., organ transplant) 5. Tolerance: induction of a state of unresponsiveness toward certain antigens (mainly self-antigens) 6. Regulation control of the immune responses to maintain hemeostasis  Inappropriate Immune responses Allergies Autoimmune diseases  Hypersensitivity Reactions ( Allergy ): is an abnormal response to antigens Autoimmunity : is the system of immune responses of an organism against its own healthy cells and tissues. Immunodeficiency: is a state in which the immune system's ability to fight infectious disease and cancer is compromised or entirely absent. OR the malfunction of the immune system. Factors affecting the Immune response species Race Individual Individual Hormonal Nutrition Thank you References Understanding Immunology, Peter Wood, 2nd edition,Chapter1,2. Immunology,D. Male, J. Brostoff ,7th Ed.,chapter 1,6. Nature Immunology Reviews.