ഗവൺമെന്റ് വി. &എച്ച്. എസ്. എസ്. കുളത്തൂർ/അക്ഷരവൃക്ഷം/ IMMUNITY SYSTEMS

IMMUNITY SYSTEMS      All organisms are connected in a complex web of relationships. Although many of these are benign not all are and everything alive devotes significant resources to identifying and neutralizing threats from other species. From bacteria through to primates the presence of some kind of effective immune system had gone hand in hand with evolutionary success. Immunity is a state of specific resistance to infection. Specific resistance is directed against a particular type of microorganism and is the single most important characteristic of immunity. This article focuses on mammalian immunity, the challenges that it faces, the mechanisms by which these are addressed and the consequences that arise when in malfunctions. Introduction The problems that the mammalian immune system solves are not restricted to higher animals; they are faced by all forms of life and are ignored by none. The pressure that natural selection exerts is inexhaustible and unending. Emerging infectious diseases have as much potential to shape future human history as the epidemics and pandemics of the past. Managing this threat depends on understanding how to maximize the potential of our sophisticated immune system in the service of human health. It is a fundamental property of immunity that no part of our body is cut off from its surveillance. For this reason, although the immune system may seem a less substantial thing than an organ such as the heart or the liver. In aggregate immunity consumes enormous resources, producing large number of cells that it depends on for successful functioning. After early childhood, most immune cells are produced from the bone marrow. Some of these then undergo very significant secondary changes before they are released to patrol the body. Many important immune cell types have been identified in a routine test. Five different kinds of white blood cell will be counted. An immunologist or a haematologist may subdivide these populations further on the basis of the proteins that are expressed in their cell membranes. Among these proteins are receptors by which cells interact with each other and the environment. Receptors bind ligands which may be receptors on other cells or soluble molecules such as cytokines. Cells express hundreds of different types of receptors on their surface. Many carry out fundamental functions such as transporting glucose into the cell. The receptors associated with the immune system are generally concerned with interrogating the environment for evidence of danger infection or abnormal cell death. In the course of an immune respone, cell follow a programme, such that the overall outcome maximize the likelihood of surviving and eliminating infection or cancer. Receptors are also present inside the cell where they play an important role, acting to detect evidence of infection organisms such as viruses can spend most of their life hidden in the complicated cytoplasm to the cell, making them difficult to recognize from the outside. Receptors within the cytoplasm can bind to virus derived signature molecules. Such as different types of nucleic acid and signal that infection is present . Cells use a sophisticated system for sampling the proteins they are making, to check that none have from viruses if cell detect such tell tale signs they respond by producing cytokinins that serve as alarm signals for surrounding tissues and by committing rapid and effective suicide that leaves a cell remnant that can initiate adaptive immunity directed at the inciting infection. All of these different responses rely on the selective expression of specific families of genes. Studies of the immune system have been at the forefront of characterizing how different gene programmes function. Immune cell read the environment through their receptors and then modify how they use the genes encoded by their DNA. Some groups of genes are switched on and others are switched off. This gives the different cell types a great deal of flexibility in how they handle an infection. Sometimes these gene programmes change the cytokinins that cells secrete, sometimes they change how resistant the cell is to infection. Information in the environment can label a specific location. CHALLENGES Discrimination Immune systems have an uneasy relationship with the environment. Most of the time an encounter with something new is harmless, but the small fraction of times that it is not can be very dangerous indeed. An effective immune system must be able to discriminate such differences, distinguishing self from non-self and distinguishing harmless non-self from dangerous non-self. For much of the 20 th century, research in immunology was focused on understanding how it achieved the former. It was spurred by an important early observation, that is was possible for animals to develop specific immune reactions against certain chemicals such as dyes which never existed previously in nature. The ability to learn how to recognize these previously known structures implied that the immune system had solved the problem of how to classify and recall the shapes of individual molecules unravelling the biological machinery that achieves this was a signature achievement of 20 th century immunology. Flexibility The immune system’s ability to adapt flexibly to strange environmental changes is critical in fighting infections and cancer. Because our bodies have a remarkable capacity for renewal and almost every cell is a factory working day and night to turn over worn out molecules, breaking them down into building blocks that are reused to make replacement infection or cancer can arise at any time. Every time a cell divided, there is a small chance that it may develop a random unpredictable mutation that will transform it into a cancer. Infections reproduce much more rapidly than their hosts and can change their appearance to allow them to evade recognition. An effective immune system must cope with its unpredictability. Managing infection For a microbial infection to develop, the pathogen must get close enough to interact with individual cells. The skin and mucous membranes make this close approach difficult. Physical barriers provide innate protection, such as the overlapping cells of the skin and chemical barrieers and enzymes such as lyzozymes and the acid in the stomach also kill many bacteria. These outward facing surfaces actually encurae the presence of non-pathogenic microbes. By welcoming and supporting a co-operating microbial population little opportunity is left for more dangerous relatives to move in. Conclusion Immunity works in a coordinated fashion to respond to numerous threats from the environment. It is essential for good health, from the moment of conception, when the mother’s immune system starts protecting the growing body, until old age. As medicine has progressed physicians have slowly learned how to apply an understanding of the fundamentals of immunology to reinforce and repurpose the immune repurpose, providing against infection or targeting cancers. Immunotherapy has been improving human health since Edward Jenner coined the term vaccination and it will have much more to contribute in the future. അപർണ എസ് രാജ് 11 VHSE ഗവൺമെൻറ്, വി.&എച്ച്.എസ്.എസ് കുളത്തൂർ പാറശ്ശാല ഉപജില്ല തിരുവനന്തപുരം അക്ഷരവൃക്ഷം പദ്ധതി, 2020 ലേഖനം  സാങ്കേതിക പരിശോധന - Remasreekumar തീയ്യതി: 20/ 04/ 2020 >> രചനാവിഭാഗം - ലേഖനം