2023 HUB105 Lec 14 Immunotherapy.pdf

Lecture 14 Immunotherapy, Acquired immunity, Aging and the immune system BChD I HUB 105 2023 Dept. Medical Biosciences University of the Western Cape  Introduction Various type of immunity in the body to protect itself from inf...

Lecture 14 Immunotherapy, Acquired immunity, Aging and the immune system BChD I HUB 105 2023 Dept. Medical Biosciences University of the Western Cape  Introduction Various type of immunity in the body to protect itself from infection from an endless supply of pathogens. The body has many defense mechanisms, however they could be divided into two categories: Innate immunity and Adaptive immunity Adaptive or acquired immunity is not present at birth and can be either active or passive immunity. Active immunity: antibodies develops only after expose to antigens. Passive immunity: antibodies are transferred into the body via another source. These types of immunity may be classified as either ‘natural’ or ‘induced’ Immunity may develop as a result of natural or induced exposure: – Natural acquired immunity (develops after exposure to antigens in the environment or by transfer of maternal antibodies in breast milk) – Artificially Induced immunity (develops after administration of antigens to prevent disease or by administration of antibodies to combat infection) Forms of Immunity Response to threats on an Immunity individualized basis Adaptive Immunity Innate Immunity Adaptive immunity is not present at birth; you Genetically acquire immunity to a specific antigen only when determined−no you have been exposed to that antigen or receive prior exposure or antibodies from antibody another source. production involved Active Immunity Passive Immunity Develops in response Produced by transfer to antigen exposure of antibodies from another source Naturally acquired Artificially induced Naturally acquired Artificially induced active immunity active immunity passive immunity passive immunity Develops after Develops after Conferred by Conferred by exposure to administration of transfer of maternal administration of antigens in an antigen to antibodies across antibodies to environment prevent disease placenta or in combat infection Eg Common cold Eg Vaccinations breast milk Eg Anti-Tetanus eg Flu/Polio injections Immunotherapy Immunotherapy refers to the type of treatment that stimulates, enhance or suppress the body’s own immune system. Assist to mainly stimulate the immune response to be more effective. Suppressing immune system is beneficial in autoimmune diseases. Initially used to treat mainly cancer but also used for inflammatory diseases eg Rheumatoid arthritis/Multiple sclerosis. Types of Immunotherapies  Biological response modifiers Substances that stimulate the body’s response to infection and disease. The body naturally produce small amounts of biological response modifiers eg cytokines, interferons. BRM provide nonspecific active immune stimulation. BRM boost the immune system by injection of cytokines such as interleukins and interferons to help treat cancer and rheumatoid arthritis. Types of Immunotherapies  Colony-stimulating factors - are substances that stimulate the growth of bone marrow stem cells, especially lymphocytes, to fight infections. - cancer treatments (radiation/chemotherapy) often destroy lymphocytes.  Monoclonal antibodies - laboratory-produced substances that can locate and bind to certain proteins. - directly attach to tumour-associated proteins found on cancer cell membranes. - used to detect tumour location in body, or as therapy to deliver toxins to cancer cells. - monoclonal antibodies spare body’s normal cells.  Tumour vaccines - researches are developing vaccines that can recognise cancer cells. - Therapeutic vaccines works after cancer has been detected and is given to prevent cancer returning. - Some traditional vaccines are used to prevent cancer caused by viruses eg Human papilloma virus (HPV) vaccine (cervical cancer), Hepatitis B vaccine for certain liver cancer. - Preventative vaccines are still in clinical trials. Effects of aging on the immune system Immune system deteriorates with age, increasing vulnerability to infections and cancer less able to distinguish self from non-self, as a result, autoimmune disorders become more common. T cells, responsible for cell-mediated immunity become less responsive to antigens. With aging involution occurs which is the shrinkage of organs, this decreases the production of T cells and thymic hormones by the thymus, this decreases cytotoxic T cell responses. Reduction in Helper T cells decreases the responsiveness of B cells, in antibody-mediated immunity, so decreases the production of antibodies. This ultimately results in increase susceptibility to viral and bacterial infections. This slowdown in the immune surveillance may be one of the reasons cancer is more common among older generation. Revision Questions 1. Define the following: active and passive immunity, immunotherapy, monoclonal-antibodies. 2. Tabulate the different forms of adaptive immunity. 3. How does immunotherapy assist the immune system? 4. Name and explain the various forms of immunotherapy. 5. Explain how and aging immune system functions.