Immunology - Innate and Acquired Immunity

Title: Innate and Acquired Immunity: Understanding the Two Branches of Our Immune System

Introduction:
The human immune system is a complex network of cells, tissues, and organs that protects us from invading pathogens and foreign substances. In this presentation, we will explore the two branches of the immune system: innate and acquired immunity. We will discuss the key features of each branch, their mechanisms of action, and how they work together to keep us healthy.

Section 1: Innate Immunity
- Innate immunity is the first line of defense against pathogens and foreign substances.
- We will discuss the key features of innate immunity, including physical barriers, such as skin and mucous membranes, and the cellular and molecular components of innate immunity, such as phagocytes and cytokines.
- We will also explore some of the ways in which innate immunity can be activated and how it responds to different types of pathogens.

Section 2: Acquired Immunity
- Acquired immunity, also known as adaptive immunity, is a more specialized and targeted response to specific pathogens or foreign substances.
- We will discuss the key features of acquired immunity, including the role of B and T lymphocytes, antibodies, and memory cells.
- We will also explore some of the ways in which acquired immunity can be activated, including through vaccination, and how it responds to specific antigens.

Section 3: Interaction between Innate and Acquired Immunity
- Innate and acquired immunity work together in a coordinated manner to provide effective protection against pathogens and foreign substances.
- We will discuss how innate immunity can initiate an immune response and activate acquired immunity, and how acquired immunity can enhance the effectiveness of innate immunity.
- We will also explore some examples of how these two branches of the immune system work together in different types of infections.

Conclusion:
Understanding the different branches of our immune system is essential for developing effective strategies to prevent and treat infectious diseases. Innate and acquired immunity work together to provide a coordinated and dynamic defense against pathogens and foreign substances. By exploring the mechanisms and interactions between these two branches of the immune system, we can gain a deeper appreciation for the complexity and power of our immune system.

1. SRI PARAMAKALYANI COLLEGE Affiliated to Manonmanium Sundaranar University (Reaccredited with A+ grade with CGPA of 3.39 in the III cycle of NAAC) ALWARKURICHI - 627412 Post graduate & Research Department of Microbiology (government aided) ACADEMIC YEAR 2023-2024 II SEM CORE:IMMUNOLOGY UNIT 1 – INNATE & ACQUIRED IMMUNITY SUBMITTED TO: DR.S.VISWANATHAN HEAD OF THE DEPARTMENT SUBMITTED BY: SHIGINA.E.S 1 st Msc .MICROBIOLOGY

2. PRE S E N T A TION OUTLINE Introduction Historical Perspective Types Cells Involved Reference Outcomes

3. Immunity Immunity is the body's capacity to protect itself from pathogenic microorganisms. Numerous microorganisms come into contact with our body on a daily basis, yet only a small number cause disease. The rationale is that our bodies have the capacity to produce antibodies that fight against harmful viruses and defend the n a m e g i v e n to t h i s body from illnesses. Immunity is the defence strategy.

4. How Immunity Confers Against Diseases The presence of antibodies to a disease in a person's system confers immunity against that disease. Proteins called antibodies are made by the body to combat or eliminate poisons or pathogens. Antibodies are specialised to diseases. For instance, a person who is exposed to the measles disease will be protected, but if that same person is exposed to the mumps, nothing will happen.

5. Historical Perspectiv e The concept of immunity has a long history, dating back to ancient times, and has evolved through the centuries as a result of advancements in medical research. The study of immunity continues to play a critical role in the prevention and treatment of diseases

6. where smallpox was treated by intentionally infecting a person with a mild form of the disease to prevent severe illness. The practice was later introduced to Europe, where it was refined by Edward Jenner in the late 18th century. Jenner discovered that milkmaids who contracted cowpox, a mild illness, were immune to smallpox, leading him to develop the first vaccine against smallpox. The concept of immunity can be traced back to ancient times, where people observed that those who survived a disease were less likely to become ill with the same disease again. This concept immunity formed the basis of the practice of inoculation, where individuals were deliberately exposed to weakened forms of a pathogen to build immunity.

7. The study of the immune system and its response to pathogens continued to advance in the 20th century, leading to the development of new vaccines, immunotherapies, and treatments for a variety of diseases. The increased understanding of the immune system has also led to new approaches for treating autoimmune diseases, cancer, and other conditions. The scientific study of immunity as a biological process began in the 19th century, with the discovery of microorganisms as the cause of many diseases and development of b a c t e r i o l o g y a s a f i e l d o f s t u d y . D u r i n g t h i s t i m e , r e s e a r c h e r s a l s o discovered that certain substances produced by the body, a n t i b o d i e s , p l a y a k e y s u c h a s r o l e i n protecting against diseases. In 20th century, of medical research the major advancements expanded u n d e r s t a n d i n g o f t h e i mm u n e system. The discovery of penicillin in 1 9 2 8 m a r k e d t h e b e g i nn i n g o f t h e antibiotic approach i n f e c t i o n s . era, providing a new to treating bacterial The d e v e l o p m e n t o f vaccines for diseases such as polio, m e a s l e s , a n d m u m p s g r e a t l y reduced the incidence of diseases.

8. Innate Immunity or Natural or Non-specific Immunity. Acquired Immunity or Adaptive Immunity. Types of Immunity

9. Stem cells into different immune cells

10. In nate Immunity An organism has this form of immunity from birth. As soon as the pathogen hits, this is immediately activated. Barriers and defence systems that prevent foreign substances from entering the body are part of innate immunity. The body's defence mechanism is referred to as innate immunity. The inherent defence mechanisms that this immunity provides, such as salivary enzymes, natural killer cells, undamaged skin, neutrophils, etc., help us fight off diseases from birth before being exposed to pathogens or antigens.

11. A c quired Immunity The immunity that our bodies develop through time is known as acquired immunity or adaptive immunity. This is not innate immunity, which is present from birth. It is particular and is carried out by lymphocytes or antibodies that render the antigen harmless. Acquired immunity's primary purpose is to both treat the infectious disease's sufferer and shield others against it in the future. It mostly comprises of an improved lymphatic defence system that recognises own bodily cells and doesn't respond to them.

12. Active Immunity The most usual form is active immunity. It manifests as a result of an illness or a vaccine. These procedures subject your immune system to a particular infection or germ (in vaccinations, just a small amount). When T and B cells, which are immunological cells, detect a "invader" infection, the immune system is triggered to combat it. The T and B immune cells will identify that particular germ the next time they come into contact with it and will instantly engage the rest of your immune system to keep you healthy.

13. Passive Immunity Passive immunity develops after you receive antibodies from someone or somewhere else. This type of immunity is short-lived, because it doesn’t cause your immune system to recognize the pathogen in the future. Passive immunity often falls into one of two categories: Maternal antibodies are antibodies that transfer from a mother to child. This usually happens across the placenta or through the breast milk. Immunoglobulin treatments are antibodies that are usually used to treat people at risk for infections, like after a snakebite or a baby born to a mother with hepatitis B.

14. Cells Involved in Immunity

15. Phagocytes: Are circulating cells that scour the body for foreign objects. When the body is protecting itself against that pathogen, they engulf and kill it. Macrophages : These can traverse the lining of the circulatory system. To enlist more cells at the location of infections, they emit specific signals like cytokines. Mast cells : These are vital for wound healing and infection defence. Natural killer cells : By eradicating the contaminated host cells, these cells prevent the spread of illnesses. Cells Involved In Innate Immunity

16. Neutrophils : The granules found in neutrophils are poisonous by nature and can destroy any pathogen that comes into touch with them. Eosinophils : These cells produce highly poisonous proteins that are lethal to any bacteria or parasite they come into contact with. Basophils : They target parasites that are multicellular. These also release histamine, just like mast cells do. Dendritic cells : Are present in the tissues where the first infections are picked up. By presenting an antigen, these cells alert the rest of the immune system to the infection..

17. Cells Involved In Aquired Immunity B Cells They develop in the bone marrow. When these cells come into contact with external substances, they are activated. The B-cells immediately differentiate into plasma cells which produce antibodies specific to that foreign particle or so- called antigen. These antibodies bind to the antigen/foreign agent's surface. Humoral immunity refers to B-cell- dependent immunity.

18. T Cells They arise in the bone marrow and mature in the thymus. T-cells majorly divided into three types: helper cells, cytotoxic cells, and regulatory cells. These cells are discharged into the circulatory system. When activated by an antigen, helper T- cells produce cytokines, which operate as messengers. These cytokines cause B-cells to differentiate into plasma cells, which then produce antibodies against antigens. T-cells that govern immunological responses are known as regulatory T-cells.

19. Types of B cells Naive B cells: These are B cells that have not yet encountered their specific antigen. Naive B cells are constantly circulating in the blood and lymphoid tissues. Memory B cells: Memory B cells are long-lived and can quickly respond to a subsequent exposure to the same antigen, leading to a faster and more robust immune response. Plasma cells: These are fully differentiated B cells that are specialized to produce large amounts of antibodies. When a B cell is activated by its specific antigen, it undergoes differentiation into plasma cells, which then secrete antibodies into the blood and lymphoid tissues.

20. Regulatory B cells: These are a subset of B cells that have immunomodulatory functions. Regulatory B cells can produce anti-inflammatory cytokines and suppress the activity of other immune cells, helping to prevent ex c essiv e immune responses that can lead to tissue damage and autoimmune diseases. Marginal zone B cells: These are a type of B cell that is located in the marginal zone of the spleen. Marginal zone B cells are specialized to respond to blood-borne pathogens, and they can quickly produce antibodies to neutralize these pathogens. B1 B cells: These are a subset of B cells that are mainly found in the peritoneal cavity and produce natural antibodies that protect against common pathogens in the gut and respiratory tract.

21. Types of T Cells H e l p e r T c e ll s : T h e s e a r e a l s o k n o w n a s CD 4 + T c e ll s , a n d t h e y p l a y a c r i t i c a l r o l e i n c oo r d i n a t i n g t h e i mm u n e r e s p o n s e . recognizes its specific When a helper a n t i g e n p r e s e n t e d T c e l l b y a n antigen-presenting cell, it undergoes activation and differentiation into different subsets of helper T cells, such as Th1, Th2, Th17, and Tfh cells. Cytotoxic T cells: These are also known as CD8+ T cells, and they are specialized to recognize and kill infected or abnormal cells. When a cytotoxic T cell recognizes its specific antigen presented on the surface of an infected or abnormal cell, it undergoes activation and differentiation into an effector cytotoxic T cell.

22. Regulatory T cells: These are a subset of T cells that have immunomodulatory functions. can suppress the activity of other immune cells, helping to prevent excessive immune responses that can lead to tissue damage and autoimmune diseases. M e m o r y T e n c o u n t e r e d c e ll s : T h e s e a r e T c e ll s their specific antigen t h a t h a v e a n d h a v e undergone activation and differentiation to produce effector T cells. Memory T cells are long-lived and can quickly respond to a subsequent exposure to the same antigen, leading to a faster and more robust immune response. Gamma-delta T cells: These are a subset of T cells that have a unique T cell receptor composed of gamma and delta chains, rather than alpha and beta chains like conventional T cells. Gamma-delta T cells are found mainly in epithelial tissues such as the skin and gut and can respond to various types of antigens.

23. Reference Kuby Immunology 7th edition. T e x t b oo k o f B a s i c a n d C l i n i c a l I mm u n olo g y b y G a n g al a n d Sontakke https://byjus.com/biology/differe nces-between-innate-and- adaptive- immunity/#:~:text=Innate%20im munity%20is%20general%20an d,Second%20line%20of%20defe nce.

24. OUTCOMES Understanding the difference between innate and acquired immunity: You will have a clear understanding of the two types of immunity and their respective roles in the immune system. Recognition of the importance of innate immunity: You will appreciate the critical role of innate immunity in providing immediate protection against a wide range of pathogens, even before acquired immunity is activated. Appreciation of the adaptive nature of acquired immunity: You will recognize that acquired immunity is capable of adapting to specific pathogens and can provide long-term protection. Knowledge of the different components of innate immunity: You will have learned about the various components of innate immunity, including physical barriers, cellular components such as neutrophils and macrophages, and molecular components such as complement proteins. Familiarity with the different components of acquired immunity: You will be familiar with the different components of acquired immunity, including B cells, T cells, and antibodies.

25. Understanding of the role of memory cells: You will understand how memory cells play a crucial role in acquired immunity by enabling the immune system to recognize and respond more quickly to previously encountered pathogens. Recognition of the importance of vaccination: You will appreciate the role of vaccination in promoting acquired immunity and protecting individuals from infectious diseases. Awareness of the potential consequences of immune dysfunction: You will be aware of the potential consequences of immune dysfunction, including autoimmune diseases, immunodeficiency disorders, and hypersensitivity reactions. Ability to apply knowledge to real-world scenarios: You will be able to apply your knowledge of innate and acquired immunity to real-world scenarios, such as understanding the immune response to viral infections or the development of new vaccines.

26. THANK YOU!