Cell Biology Immunology Chapter 1 PDF

Cell Biology 2nd year CCNLS 2024/2025 Chapter N°1 Introduction to Immunology 1. Immunity The term immunity is derived from the Latin word “immunis”, which was originally...

Cell Biology 2nd year CCNLS 2024/2025 Chapter N°1 Introduction to Immunology 1. Immunity The term immunity is derived from the Latin word “immunis”, which was originally referred to the protection. This term was adopted subsequently to designate the naturally acquired protection against diseases, such as measles or smallpox. It indicated that an individual can develop lifelong resistance to a certain disease after having contracted it only once. The cells and molecules responsible for immunity constitute the immune system, and their collective and coordinated response to foreign substances is called the immune response. 2. Historical Perspectives: Key Discoveries in Immunology Understanding immunology has evolved over centuries through key discoveries and experiments: 2.1. Early Concepts of Immunity: In ancient times, it was observed that people who survived certain diseases, like smallpox, became resistant to future infections. 2.3. 1796 – Edward Jenner and the First Vaccine: Smallpox vaccination: Jenner noticed that milkmaids who contracted cowpox (a less severe disease) did not get smallpox. He developed the first vaccine by injecting material from cowpox sores into a boy, who then became immune to smallpox. This marked the birth of immunology as a science. 2.3. 1880s – Louis Pasteur’s Experiments: Pasteur expanded on Jenner's work by developing vaccines for rabies and anthrax, introducing the concept of attenuated (weakened) pathogens to stimulate immunity. 2.4. 1890 – Emil von Behring and Antitoxins: Behring demonstrated that antibodies (then called antitoxins) in the blood could neutralize toxins from diphtheria and tetanus, leading to passive immunity (transferring immunity from one individual to another). 2.5. 1901 – Discovery of Blood Groups (Karl Landsteiner): Discovery of ABO blood groups paved the way for safe blood transfusions and highlighted the role of the immune system in recognizing foreign antigens. 2.6. 1950s-1970s – Clonal Selection Theory and Immune System Complexity: Frank Macfarlane Burnet proposed the clonal selection theory, explaining how specific immune cells recognize unique antigens. Discovery of T cells and B cells, and the understanding of cell-mediated and humoral immunity. 2.7. 1975 – Development of Monoclonal Antibodies: Georges Köhler and César Milstein developed techniques to produce monoclonal antibodies, which are identical antibodies targeting a specific antigen. This revolutionized diagnostics and therapies. 1 Dr. KRIM M. Cell Biology 2nd year CCNLS 2024/2025 2.8. 1980s – Discovery of HIV/AIDS: Research into the HIV virus provided insights into immune deficiency and how viruses can evade immune responses. 2.9. 2000s to Present – Advances in Immunotherapy: The development of checkpoint inhibitors and CAR-T cell therapies for cancer. mRNA vaccines (e.g., for COVID-19) represent a major breakthrough in vaccine technology. Figure: Smallpox. 3. Immune terminology  Immunology: It refers to the science of immunity and the components of immune system of the body that deal with foreign invaders. Applied and therapeutic immunology includes the understanding of immune disorders and immunotherapy, i.e., to be able to treat these diseases.  Chronic health condition: A health-related state that lasts for a long period of time (e.g. cancer, asthma).  Booster shots: Additional doses of a vaccine needed periodically to "boost" the immune system.  Bacteria: Tiny one-celled organisms present throughout the environment that require a microscope to be seen. While not all bacteria are harmful, some cause disease.  Asymptomatic infection: The presence of infection without symptoms.  Antigens: Foreign substances (e.g. bacteria or viruses) disease in the body are capable of causing disease. The presence of antigens in the body triggers an immune response, usually the production of antibodies.  Antibody: A protein found in the blood that is produced in response to foreign substances (e.g. bacteria or viruses) invading the body. Antibodies protect the body from disease by binding to these organisms and destroying them. 2 Dr. KRIM M. Cell Biology 2nd year CCNLS 2024/2025  Active immunity: The production of antibodies against a specific disease by the immune system.  Acute: A short-term, intense health effect.  Allergy: A condition in which the body has an exaggerated response to a substance (e.g. food or drug.) Also known as hypersensitivity.  Disease: Sickness, illness, or loss of health.  Etiology: The cause of.  Exposure: Contact with infectious agents (bacteria or viruses) in a manner that promotes transmission and increases the likelihood of disease.  Immune globulin: A protein found in the blood that fights infection. Also known as gamma globulin.  Immune system: The complex system in the body responsible for fighting disease. Its primary function is to identify foreign substances in the body (bacteria, viruses, fungi, or parasites) and develop a defense against them. This defense is known as the immune response. It involves the production of protein molecules called antibodies to eliminate foreign organisms that invade the body.  Immunity: Protection against a disease.  Immunization: The process by which a person or animal becomes protected against a disease. This term is often used interchangeably with vaccination or inoculation.  Immune Tolerance: Immune tolerance is the state of unresponsiveness of the immune system to substances or tissues that have the potential to induce an immune response.  Inflammation: Redness, swelling, heat and pain resulting from injury to tissue (parts of the body underneath the Skin).  Microbes: Tiny organisms (including viruses and bacteria) that can only be seen with a Microscope.  Macrophage: A large cell that helps the body defend itself against disease by surrounding and destroying foreign organisms (viruses or bacteria.).  Memory Cell: A group of cells that help the body defend itself against disease by remembering prior exposure to specific organisms (e.g. viruses or bacteria). Therefore, these cells are able to respond quickly when these organisms repeatedly threaten the body.  Phagocyte: An immune cell that is able to ingest and destroy microbes and other foreign matter. 4. Applications of Immunology in Medicine and Health Immunology has a profound impact on many areas of health and medicine: 3 Dr. KRIM M. Cell Biology 2nd year CCNLS 2024/2025 4.1. Vaccination: Preventive vaccines (e.g., measles, hepatitis B, influenza) protect millions of people from infectious diseases. Therapeutic vaccines are being developed to treat diseases like cancer. 4.2. Treatment of Autoimmune Diseases: Diseases like rheumatoid arthritis, lupus, and multiple sclerosis occur when the immune system attacks the body’s own tissues. Immunosuppressive drugs are used to control these reactions. 4.3. Organ Transplantation: Understanding immune responses is crucial for organ and tissue transplantation. Anti-rejection drugs help prevent the immune system from attacking transplanted organs. 4.4. Cancer Immunotherapy: Techniques like checkpoint inhibitors and CAR-T cell therapy enable the immune system to recognize and destroy cancer cells. 4.5. Allergy Treatment: Allergies result from hypersensitive immune responses to harmless substances (e.g., pollen, food). Antihistamines, immunotherapy, and desensitization techniques are used to manage allergies. 4.6. Infectious Disease Control: Monoclonal antibodies and antiviral drugs are key in managing diseases like COVID-19, Ebola, and influenza. Immune profiling helps understand and manage emerging infectious diseases. 4.7. Development of Diagnostic Tools: Immunoassays like ELISA and Western blot are used in disease diagnosis. Rapid diagnostic tests for infections (e.g., HIV tests, pregnancy tests). 4.8. Research and Development: Immunology is at the forefront of genetic engineering (e.g., CRISPR) and biotechnology. 4 Dr. KRIM M.