Immunity 305 AMB Lecture 1 PDF

Immunity 305 AMB  Lecture 1 Immune system Lecture’s objectives By completion of the lecture, you should be able to:  Define the immunity.  Know what is the immune system?  Understand the concept of immunity.  Know the bra...

Immunity 305 AMB  Lecture 1 Immune system Lecture’s objectives By completion of the lecture, you should be able to:  Define the immunity.  Know what is the immune system?  Understand the concept of immunity.  Know the branches of immune system  Determine the function levels of immune system  Determine the lines of body defense  the basic elements of the immune system  Understand the role of anatomical and biochemical barriers in body protection. Dr. Ferial M. Rashad Lecture 1  Immune system The word immunity is derived from the Latin stem immunis, meaning safe or free from burden. Dr. Ferial M. Rashad Lecture 1  Immune system  Each of us has a complex system gives us immunity or freedom from the potentially harmful interaction with microbes.  It is called the immune system.  In simple words: Our immune system regulates our interaction with microbes. Dr. Ferial M. Rashad Lecture 1 Immune system  The immune system is the body’s defense system.  It acts as body’s police and army forces in detecting invaders (pathogens and parasites, harmful molecules), cleaning up vandalism (dead cells) and subsequently protecting us against foreign invaders and harmful molecules. (against pathogens and harmful molecules)  AN IMMUNE RESPONSE Foreign invaders - viruses, bacteria, allergens, toxins and parasites - constantly attack our body.     Our immune system regulates our interaction between microbes with the ultimate goal to eliminate the invaders through both pathogen- specific and non-specific mechanisms. 6 Dr. Ferial M. Rashad Lecture 1  Immune system our immune system functions at tow clearly defined (distinct) levels through 2 types of mechanisms: 1. Nonspecific or nonselective mechanisms making up what is called natural or innate immunity. 2. Specific or selective mechanisms making up what is called acquired or adaptive or specific immunity. Dr. Ferial M. Rashad Lecture 1  Immune system  Our immune system is divided into two branches, or arms, the 'Innate' and 'Adaptive' arms of the immune system.  Each arm can function independently (individually), or more often, together. Dr. Ferial M. Rashad Lecture 1  We can summarize the previous part as follow Our immune system regulates our interactions with invaders with an ultimate goal the elimination of them through: 2 types of mechanisms 2 branches or arms of immunity 3 lines of defense. All of them Dr. Ferial M. Rashad Lecture 1  our immune system has 3 lines of defense, this system takes a pyramid shape: 1. at the base, the first line of defense which represents anatomical and biochemical barriers (the 1st and 2nd nonspecific mechanisms); 2. at the middle of pyramid, the second line of defense which includes phagocytes and natural killing cell (the 3rd nonspecific mechanism); 3. at the top, the acquired immunity, where B and T lymphocytes that are responsible for the development of acquired immunity. Dr. Ferial M. Rashad Lecture 1  Innate Immunity It is the bedrock of immunity in all organisms. It regulates broad limits for microbial interaction through nonspecific or nonselective mechanisms. These mechanisms make up what is called natural immunity. These non-specific mechanisms are fully functional at birth without previous contact with pathogens. It is characterized by rapid response against broad range of microbes. Dr. Ferial M. Rashad Lecture 1  Innate immunity When microbes first come into contact with our bodies, they face three main mediators: 1. Anatomical or physical barriers 2. Antimicrobial biochemical barriers 3. Cellular immune defense These mediators are the non-specific mechanisms. Each mechanism has the ability to interact with invaders even if we never had previously infected with them. Dr. Ferial M. Rashad Lecture 1  Anatomical or physical barriers 1. Skin is a complex layer of epithelial cells. It provides us protection if it is intact without scratch or abrasion. 2. Ciliated epithelial cells in the respiratory tract that remove the microbes by sweeping. (Ciliated epithelial cells move microbes up and out enabling microbes to be swallowed or coughed out). Dr. Ferial M. Rashad Lecture 1  Antimicrobial biochemical barriers 1. Mucus (sticky substances) 2. Fatty acids 3. High Acidic environments in gastric juice and adult vagina. 4. Lysozyme 5. Complement 6. interferon Dr. Ferial M. Rashad Lecture 1  Anatomical and biochemical antimicrobial barriers act along together for example: Skin The intact skin as physical barrier plus inhibitory effect of chemical barrier such as : Saturated and unsaturated fatty acids secrete by sebaceous glands and by normal resident skin microbiota. High salt concentration in drying sweat. Dr. Ferial M. Rashad Lecture 1 Respiratory tract Mucous membrane lining our respiratory tract is composed of specialized epithelial cells which secretes a sticky substances known as mucus act as a chemical barrier in trapping dust and microbes. The trapped dust and microbes move up and out by ciliated epithelial cells enabling them to be swallowed and coughed out. The trapped dust and microbes are swept into throat by the ciliated epithelial cells present as a physical barrier Dr. Ferial M. Rashad Lecture 1 Lysozyme: It presents in most tissue fluids such as tears, saliva, nasal secretions except urine, sweat and cerebrospinal fluids (CSF). It degrades the peptidoglycan and disrupt the bacterial cell. It is easy to access directly to the peptidoglycan, so it is more effective against G+ve than G-ve. in G-ve , outer membrane Gram Negative Gram Positive Outer membrane Cell Thin layer of Thick layer of membrane peptidoglycan Peptidoglycane Dr. Ferial M. Rashad Lecture 1 Complement system: alternative pathway Complement is an enzyme system consisting of at least 11 Proteins. It is present in all normal sera. A major serum complement protein can be activated through alternative or innate pathways. Interferon  There are tow types of interferon,α andβ as a part of innate immunity.  It does not stop viral infection directly.  It is a biochemical signal for the neighbor cell to synthesize AVPs.  AVPs are the real mediators of virus resistance.  AVPs are enzymes prevent virus assembly and maturation.  Viral infected cell Signal to host cell 1. Viral replication activates Nucleus host cell gene for interferon Interferon synthesis. The gene Nucleus antiviral 2. Interferon is synthesized action of and released by the infected interferon: host cell. Signal to host cell 3. Interferon binds to The Nucleus AVPs surface of neighboring cell sequence APVs and induces synthesis of genes of events. antiviral proteins, AVPs. AVPs disrupt the final steps 4. Cell synthesized AVPs of that block viral replication. viral assembly Dr. Ferial M. Rashad Lecture 1  References  Prescott et al. (2002). Microbiology, 5th Ed. The McGraw−Hill Com, 1147 P.  Arora, D. R. (2004). Textbook of Microbiology, 2nd Ed. CBS India, 686 P.  Cruse et al. (2004). Immunology Guide book. Elsevier USA, 502 P.  Arora, D. R. and Arora, B. (2008). Text book of Microbiology, 3rd Ed. CBS India, 771 P.  Hay, F. C. and Westwood, O. M. (2002). Practical immunology, 4th Ed. Blackwell Science, 400 P. Dr. Ferial M. Rashad Lecture 1 References  World of microbiology and immunology. KL Lerner, BWLerne. The Gale Group, Inc, 2003. 42, 2003. Gale Encyclopedia of Science. Volume 6. KL Lerner, BW Lerner Gale, 2004. 27, 2004. World of forensic science. KL Lerner, BW Lerner. Thomson Gale, 2006. 16, 2006. Encyclopedia of espionage, intelligence, and security.  Sompayrac, L. (2012). How the Immune System Works, 4th Ed. USA- Wiley-Blackwell, 141 P.  Paul, W. E. (2013). Fundamental Immunology, 7th Ed. Philadelphia- Wolters Kluwer Health/Lippincott Williams & Wilkins, 1283 P.  Male, D.; Brostoff, j.; Roth, D. B. and Roitt, I. V. (2013). Immunology-Student Consultant, 8th Ed. Elsvier, 472P. http://pathmicro.med.sc.edu/book/immunol-sta.htm... etc  Abul K. Abbas, Andrew H. Lichtman, Shiv Pillai (2021). Cellular and Molecular Immunology, 10th Edition. https://vetbooks.ir/cellular-and- molecular-immunology- 10th-edition/ Dr. Ferial M. Rashad Lecture 1