Define immunity and its types

• 1 Active Immunity • 1.1 Natural • 1.2 Artificial • 2 Passive Immunity • 2.1 Natural • 2.2 Artificial • 3 Active vs. Passive Immunity – Summary • 4 Clinical Relevance – Immunoglobulin Therapy The body relies on the adaptive immune system and immunological memory to provide immunity and prevent recurrent infections with the same illness. This can also be taken advantage of within medicine through things such as vaccinations. The various ways in which immunity is developed are generally split into ‘active’ (i.e. due to the body’s own immune response and immune cells) and ‘passive’ (i.e. as a result of antibodies) immunity. This article will consider the different types of immunity and finally, their roles within the immune system. Active Immunity Active immunity is when the body’s own immune system mounts an adaptive immune response following direct exposure to a disease organism or antigen. It can develop either naturally or artificially. Active immunity, in contrast to passive immunity, takes time to develop but is long-lasting as it produces memory lymphocytes that recognise the disease and promptly produce the antibodies needed to fight it. Natural Generally speaking, natural active immunity happens after infection with the actual disease. Exposure to the pathogen and the subsequent immune response produce memory cells that can recognise and rapidly respond to the pathogenic agent on re-exposure. Artificial Vaccination can artificially stimulate active immunity. In brie...

Lymphocytes are a type of white blood cell. They help your body’s immune system fight cancer and foreign viruses and bacteria. Your lymphocyte count can be taken during a normal blood test at your healthcare provider’s office. Lymphocyte levels vary depending on your age, race, sex, altitude and lifestyle. Overview What are lymphocytes? Lymphocytes are a type of white blood cell. They play an important role in your • T lymphocytes (T cells): T cells control your body’s immune system response and directly attack and kill infected cells and tumor cells. • B lymphocytes (B cells): B cells make antibodies. Antibodies are proteins that target viruses, bacteria and other foreign invaders. Function What do lymphocytes do? Lymphocytes help your body’s immune system fight cancer and foreign viruses and bacteria (antigens). Lymphocytes help your immune system remember every antigen it comes in contact with. After an encounter, some lymphocytes turn into memory cells. When memory cells run into an antigen again, they recognize it and quickly respond. This is why you don’t get infections like How do T cells and B cells work? Your T cells and B cells work together. They each have different roles in your immune system. Your T cells help kill infected cells and control your body’s • Cytotoxic (killer) T cells: Cytotoxic T cells attach to antigens on infected or abnormal cells. Then, they kill the infected cells by making holes in their cell membranes and inserting enzymes into the cells....

2. The mechanisms by which this is achieved. Immunity is achieved by an individual through one of three routes: natural or innate immunity genetically inherited or acquired through maternal antibody, acquired immunity conferred after contact with a disease, and artificial immunity after a successful vaccination Also termed specific immunity, resistance or specific resistance, specific immunity is divided into cellular immunity, acting via the direct involvement of T cells and humoral immunity involving antibodies and B cells. See The regulatory and cytotoxic activities of T cells during the specific immune response. This process requires about 36 hr to reach its full effect. Synonym: T-cell–mediated immunity See: illustration; Unlike B cells, T cells cannot recognize foreign antigens on their own. Foreign antigens are recognized by antigen-presenting cells (APCs) such as macrophages, which engulf them and display part of the antigens on the APC's surface next to a histocompatibility or “self-” antigen (macrophage processing). The presence of these two markers, plus the cytokine interleukin-1 (IL-1) secreted by the APCs activates CD4 helper T cells (T H cells), which regulate the activities of other cells involved in the immune response. CMI includes direct lysis of target cells by cytotoxic T cells, creation of memory cells that trigger a rapid response when a foreign antigen is encountered for the second time, and delayed hypersensitivity to tissue and organ transplants. ...

How the polio vaccine changed the world The challenge in vaccine development consists in devising a vaccine strong enough to ward off infection without making the individual seriously ill. To that end, researchers have Inactivated vaccines are those that contain organisms that have been killed or inactivated with subunit vaccine, which is made from disease year *Vaccine recommended for universal use in U.S. children. For smallpox, routine vaccination was ended in 1971. **Vaccine developed (i.e., first published results of vaccine usage). ***Vaccine licensed for use in United States. smallpox * 1798 ** rabies 1885 ** typhoid 1896 ** cholera 1896 ** plague 1897 ** diphtheria * 1923 ** pertussis * 1926 ** tetanus * 1927 ** tuberculosis 1927 ** influenza 1945 *** yellow fever 1953 *** poliomyelitis * 1955 *** measles * 1963 *** mumps * 1967 *** rubella * 1969 *** anthrax 1970 *** meningitis 1975 *** pneumonia 1977 *** adenovirus 1980 *** hepatitis B * 1981 *** Haemophilus influenzae type b * 1985 *** Japanese encephalitis 1992 *** hepatitis A 1995 *** * 1995 *** 1998 *** rotavirus * 1998 *** human papillomavirus 2006 2019

Immune memory is a defining feature of the acquired immune system, but activation of the innate immune system can also result in enhanced responsiveness to subsequent triggers. This process has been termed ‘trained immunity’, a de facto innate immune memory. Research in the past decade has pointed to the broad benefits of trained immunity for host defence but has also suggested potentially detrimental outcomes in immune-mediated and chronic inflammatory diseases. Here we define ‘trained immunity’ as a biological process and discuss the innate stimuli and the epigenetic and metabolic reprogramming events that shape the induction of trained immunity. The vertebrate immune system has traditionally been divided into innate and adaptive arms. Cells of the innate immune system recognize pathogens and tissue damage through germline-encoded For a long time it was assumed that immunological memory was an exclusive hallmark of the adaptive immune response. However, a growing body of literature indicating that innate immune cells — and even tissue-resident stem cells — can show adaptive characteristics has challenged this dogma These studies have led to the hypothesis that the innate immune system also exhibits adaptive characteristics, a property that has been termed ‘trained immunity’. Understanding the properties of trained immunity will result in a better understanding of host defence mechanisms and the pathogenesis of immune-mediated diseases. The conceptual and mechanistic adva...