Immunology (PHT-321) PDF

 Immunology (PHT-321) Outline of the Course Basic Concept of Immunity and Immune Systems Overview of the immune system's role in defending the body. Key components and functions of the immune system. The Innate Immune System First line of...

 Immunology (PHT-321) Outline of the Course Basic Concept of Immunity and Immune Systems Overview of the immune system's role in defending the body. Key components and functions of the immune system. The Innate Immune System First line of defense mechanisms: physical barriers, chemical defenses, and cellular responses. Key players: phagocytes, natural killer cells, and cytokines. The Adaptive Immune System Characteristics of adaptive immunity: specificity and memory. Role of B cells, T cells, and antibodies in targeting specific pathogens. Vaccines Principles behind vaccine development and function. Types of vaccines: live attenuated, inactivated, subunit, and mRNA vaccines. Clinical Aspects of Immunity Immunodeficiencies, hypersensitivities, and autoimmune disorders. Immunoassays and Immunodiagnostics Techniques for detecting and measuring immune responses.  Basic concept of Immunity and Immune System Introduction, Terminology and Types of Immunity Immunology: PHT-321 Dr. Amnah Alalmaie [email protected] Dr. Mohammad Khalid [email protected] Outline of Lecture 1: 1.1. Terminologies in Immunology 1.2. Classification of Pathogen 1.3. Immune System Overview 1.4. Innate Immune System 1.5. Adaptive Immune System  Learning Objectives of Lecture 1 Define the terminology of immunology Classify pathogens and categorize them into various groups based on their characteristics and properties. Describe the mechanisms used by the body to defend itself Differentiate innate and adaptive immunity in terms of components and type of immune response.  1.1. Terminologies in Immunology Immune system: The immune system is a complex network of cells, tissues, and molecules that plays a pivotal role in recognizing and responding to foreign pathogens Immunology: Study of the immune system Immunity (immunis- Latin-exempt) = State of protection from infectious diseases Immune response : Collective and coordinated response involves production of antibodies and generation of specialized lymphocytes against specific antigens. Antigen: Molecules from a pathogen or foreign organism that provoke a specific immune response. Antibody: Proteins that Recognize Specific Antigens  Pathogens: Microorganisms causing disease Microorganisms: Tiny living organisms, including bacteria, viruses, fungi, and parasites. Pathogenicity: Ability of the microorganisms to cause infection. Virulence: Degree of pathogenicity. Invasiveness: Ability of microorganism to enter host tissue, spread and multiply freely Toxigenicity: Ability of microorganism to produce toxin  Review Questions on Section 1 Question 1: What is the immune system, and what's its main job? Question 2: What's an antigen, and how does your immune system react to it? Question 3: What are pathogens, and why are they a concern for our health? Question 4: What's the difference between pathogenicity and virulence?  1.2. Classifications of Pathogen Bacteria: Single-celled prokaryotic organisms with diverse shapes and functions. Viruses: infectious agents containing genetic material within a protein coat. Fungi: Eukaryotic organisms including yeasts and molds. Parasites: Organisms living on or within a host, often causing harm. Pathogens Interaction to Host What a pathogen must do in order to cause disease? 1. Gain access to the body 2. - Attach to and/or enter cells of its host - Receptors on pathogen must fit, lock-and-key, with receptor sites on host cell 3. Reproduce while avoiding host’s immune system long enough to produce harmful changes  Normal Flora What is the normal flora? - Microorganisms naturally present in/on human body Beneficial role in health and body functions - - Protect the body by competing with potential pathogens. This is called microbial antagonism How? – Consuming nutrients that would otherwise be available to pathogens – Normal flora play a role in educating the immune system. They help train immune cells to recognize harmless substances, distinguishing them from true threats. – Normal flora of the intestines improve our overall health by producing several types of vitamins  Review Questions on Section 2 Question 1: What are the key differences between bacteria and viruses? Question 2: What are the essential steps that a pathogen must go through to cause a disease? Question 3: How do the normal flora in our bodies contribute to our protection against harmful pathogens? 1.3. Immune System Overview  Why do we need an immune system? – To protect against disease causing agents such as viruses, bacteria, fungi, protozoans, parasites…etc – To fight abnormal tissues and cells How does this work efficiently and without killing us? – Recognition of what does belong in your body, or what is “self” vs. what does not belong in the body, or what is “foreign” (not self). – All “self” cells have a recognizable complement of surface markers. – Foreign cells and structures have non-self markers which are capable of being recognized by our immune system.  Two Types of Immunity 1. Innate (non-specific) – The less specific immune component – First line of defense against infection – relies on mechanisms that exist before infection 2. Adaptive or Acquired (specific) – The highly specific immune component – Second line of defense (if innate fails) – Capable of recognizing, eliminating, and remembering specific pathogens  1.4. Innate Immune System Based on genetic make-up Relies on already formed components Rapid response: within minutes of infection Not specific – same molecules / cells respond to a range of pathogens Has no memory – same response after repeated exposure Does not lead to clonal expansion The body’s first line of defense consists of different types of barriers that keep most pathogens out of body tissues. If pathogens manage to breach the barriers protecting the body, then one of the first active responses of the innate immune system kicks in. This response is inflammation. The inflammatory response is the second line of defense Second line of defense involves immune cells: Cells involved in the innate immune response include mast cells, natural killer cells, and white blood cells, such as monocytes, macrophages and neutrophils  Phagocytosis - Phagocytosis refers to the process by which certain living cells called phagocytes engulf other cells, particles and even pathogens. - Phagocytes include white blood cells of the immune system, such as monocytes, macrophages, neutrophils, and mast cells Summary  Review Questions on Section 3 Question 1: What is the innate immune system, and how does it act as the first line of defense against pathogens? Question 2: Describe the process of phagocytosis. How do phagocytes play a crucial role in the innate immune response?  1.5. Adaptive Immune System (Acquired Immunity) Based upon resistance acquired during life Microorganisms that overcome the innate non- specific immunity come up against the host's second line of defense. Specific - Each cell responds to a single epitope on an antigen Responds more slowly, over few days Has memory - Depend upon having previous contact with a particular microorganism - Repeated exposure leads to faster, stronger response Leads to clonal expansion  Adaptive Immunity: Second Line of Response Antigens of the invading microorganism come in contact with cells of the immune system (macrophages and lymphocytes) to initiate the acquired specific immunity which may be:- - Humoral immunity (through antibodies) - Cell-mediated immunity (cytotoxic effects)  Adaptive Immunity Mechanisms Humoral immune response (HIR) – B-lymphocytes – mediated by antibodies – eliminate extra-cellular microbes and their toxins Cell-mediated immune response (CMIR) – T-lymphocytes – eliminate intracellular microbes that survive within phagocytes or other infected cells Adaptive Immunity: Active and Passive  Review Questions on Section 4 Question 1: How does adaptive immunity differ from innate immunity in terms of its response to specific pathogens? Question 2: Can you explain the concept of memory in adaptive immunity and how it helps the body fight off infections more effectively?  Adaptive and Innate - Interactions Infectious Innate Immunity No Exposure holds Disease Innate Immunity Fails Adaptive Immunity Specific memory Disease Adaptive Second Infectious Recovery Exposure Immune system Same organism Thank You