MDPARAS 2.pdf

 fluids. -Epithelium physical barrier protects body from pathogen -Adaptive longer body knows how to kill or eliminate the...

 fluids. -Epithelium physical barrier protects body from pathogen -Adaptive longer body knows how to kill or eliminate the pathogen INTRODUCTION OF IMMUNOLOGY 1. Immunity- state of protection from infectious disease (In Link between innate and adaptive immunity 430 BC, those who recovered from the plague in Athens, Greece would not contact the disease for the second time) 2. Agents- microorganisms (viruses, bacteria, etc.) and their products, food, chemicals, pollen, tumor cells, etc. 3. Immune system -immune tissues and organs, immune cells, immune molecules 4. Immune response- collective and coordinated response to the introduction of foreign substances (body can’t recognize). 5. Immunology- study the structure of immune system and its functions. Immune Response A. Innate immune response: Natural immune response & Non-specific immune response Lymphocytes B. Adaptive Immune Response: Acquired immune Response 1. Lymphocytes (except NK cells) are wholly & Specific immune response responsible for the specific immune recognition of Characteristics Cells Molecules pathogens, so they initiate adaptive immune Innate Responds Physical Humoral factors responses. immunity rapidly barriers Complement No memory Phagocytes Acute phase 2. Lymphocytes are derived from bone-marrow stem No or low (PMNs and proteins cells. specificity macrophages) Cytokines Natural killer 3. B lymphocytes develop in the bone marrow. cells T lymphocytes develop in the thymus. Adaptive Responds T cells Antibodies immunity slowly (cells B cells Cytokines to recognize Dendritic Granzymes (cell the cells death-inducing pathogen) enzymes) Memory Highly specific Innate and Adaptive Immune Response 3 Antigen presenting cells (APC) 4. function: local (mucosal) immunity 1. Dendritic cells (DC): powerful in antigen processing and presentation. 2. Macrophage: powerful in antigen processing and destruction, but low in antigen presentation. Natural killer cells (NK) 1. 5-10% of blood lymphocytes 2. express neither T-cell nor B-cell 3. Play a major role in the host rejection of tumor and viral-infected cells Phagocytic cells Monocytes (blood)/Macrophages (tissues) Functions: Immunopathology 1. Remove particulate antigens Hypersensitivity: overactive immune response 2. Take up , process and present antigenic peptides to Immunodeficiency: ineffective immune response T cells Autoimmunity: inappropriate reaction to self antigens Distribution: Kupffer cells in the liver, microglial cells in the brain INTRODUCTION OF IMMUNOLOGY 1. Empirical Immunology (AD 1700-1900) 2. Scientific Immunology (1900-1950s) 3. Modern Immunology (1960s-Present) Polymorphonuclear granulocytes Documents show that as early as AD 1000, the 1. Neutrophils; basophils;eosinophils ancient chinese custom existed of having children 2. Neutrophils are short-lived phagocytic cells multilobed inhale powders made from crusty skin lesions of nucleus; 10-20 μm 3. Neutrophils have a large arsenal of antibiotic proteins patients recovering from small pox 4. Granules: lysosomes; lactoferrin Tissues and organs of the immune system Primary (or central) lymphoid organs: Bone marrow & thymus Secondary (or peripheral ) lymphoid organs Spleen, lymph nodes, Mucosal-associated lymphoid tissue (MALT) Mucosal immune system (MIS) 1. Non-encapsulated lymphoid tissue in the lamina propria and submucosal areas of the gastrointestinal, respiratory and genitourinary tracts. 2. tonsil, appendix, Peyer’s patches 3. B cell, IgA 4  Louis Pasteur (1822-1895) Pasteur was able to provide the solution to many problems: the spoilage of beers and wines, with the accompanying pasteurization process; the discovery of anaerobic bacteria, virus vaccine, and attenuation of virulence; and studies of spontaneous generation. His studies in immunology have rightly earned him the position as father of the science. Von Behring (1854-1917) discovered the antitoxin and the principles of Antibody Diversity antiserum therapy. He established one of the first Susumu Tonegawa is a Japanese Scientist who won the corporations to produce immunologic products. Nobel Prize for physiology or medicine in 1987 “for his Elie Metchnikoff (1845-1916) discovery of the genetic principle for generation of antibody converted his discoveries of phagocytosis into a diversity” doctrine that gained many disciples from his coterie of students. He shared the Nobel Prize with Ehrlich in 1908. Paul Ehrlich (1854-1915) Selective theories (Paul Ehrlich, 1900) the binding like the fitting of a lock with key, the side chain specificity was determined before its exposure to Ag, and the Ag selected the appropriate side-chain receptor. He shared the Nobel prize with Metchnikoff in 1908. MHC (Major Histocompatibility Complex) THE DEFENDERS: Surviving in a Microbial World Ensure that many are available, act at body surface to include invaders any failure will result in disease or death Pathogenesis: cause of disease The defense of the body is encompassed by the discipline multiple defense systems , effective resistance to destroy specific organisms protection of the body depends on complex Basic arrangement of the innate and adaptive immune systems Monoclonal Ab 5  -The innate immune system consists of a collection of subsystems. -Innate immunity present in all animals that need not be -Cellular: Neutrophils, Macrophages, Mast cells, induced by prior to exposure to an infectious agent. Mediated by Lymphoid cells, Basophils, Eosinophils proteins encoded in the germ line. -Physical barriers - Adaptive immunity (back up) recognizes foreign invaders and -time and persistence will eventually overcome adapts. It improves with experience which means the second physical obstacles, most microbial attempts at exposure would work better than the first time. invasion are rapidly blocked which results in a disease or pathogenesis. -Pathogens (macrophages of the skin, get into skin lead to -All animals or plants even the least evolve need inflammation) to detect or evolve microbial invaders that -Inflammation= response to tissue injury includes parasitic invaders as fast as effectively -Antigen capture and processing by specific cells of the immune as possible. system which trigger or activate the production of T or B cell -This immediate response is the task of innate lead to Immunologic Memory and Pathogen Elimination. immune system. Many innate immune systems Three major barriers that protect an animal’s body against developed overtime and the mammalian innate microbial invasion: system therefore a diverse collection of 1. Physical barriers subsystems. That work through different 2. Innate immunity mechanisms. 3. Adaptive immunity -Collectively they all respond to block microbial invasion and minimize tissue damage. Innate responses are activated immediately when a pathogen penetrates the epithelial/physical barriers. This responses are generic, they detect microbes such as bacteria, viruses,parasites because they differ structurally and chemically from animal tissues. -Once the invaders are recognized, multiple -The successful excusion of microbial envaders is essential for innate responses are available to destroy them. survival, it is not surprising that the animal body employs An example would be animals make many multiple overlapping layers of defense. different microbial proteins that either kill the invaders directly or promote their distraction by -Physical barriers (macrophages underneath the skin, intact defense cells. Some of these molecules are skin, if skin is damaged then microbes can invade) present in normal tissues all the time. While -Self-cleaning processes (natural occur in the body) (coughing, others, are produced in response to the presence sneezing, vomiting, diarrhea, urine flow) of bacteria viruses or parasites or cell and even - tissue damage. Other rely on rapid cellular responses to a The innate immune system consists of a collection of particular invasion. Thus the body employs subsystems. Special cells that can detect invading bacteria or 6  viruses. Inflammation is central to the innate infected cells. defenses of animal body some of the cells in inflammation may also help repair damaged tissues. Once invading microbes have been destroyed. It’s the presence of a combination microbial induced tissue damage as well as inflammation that results in the set of animal behaviors that is called sickness. lack any form of memory and treated infection is identically. The intensity and duration of innate responses as inflammation for example will remain unchanged no matter how often a specific invader is countered this responses also come at a price. -Both cellular and humoral will create a response to a particular foreign invasion The time course of innate and adaptive immunity Flow diagram showing the essential features of the humoral and cell-mediated adaptive immune responses - Surface Barrier provide immediate protection. - Innate mechanisms provide rapid protection that keeps microbial or parasitic invaders at bay until they adaptive community can develop. The physical barriers would react immediately to foreign invasion. Innate immunity can act to it immediately (Non- specific). - Adaptive immunity will be developed such that it will create memory and it will take sometime it is not immediate (days or weeks to become effective). - Note: Natural killer (NK) cells are a family of innate cells that can kill tumors and virus- Adaptive immunity 7