The production of antibodies against a specific agent by the immune system is known as active immunity. This particular immunity process is there to keep you healthy. Active immunnity can be acquired in two ways: naturally by contracting an infectious disease or artificially by receiving a vaccination. Active immunity is natural and permanent; protecting individuals from disease their entire lives. This process can take place quickly by large amounts of medicines at one time. It can also take place by small amounts of medicines provided over a long period of time. Active immunity is not the expulsion of the disease but the development of the materials the body needs to do so. The immune system is a biological structure and processes within an organism that protects against disease by identifying and killing pathogens and tumor cells. It detects a wide variety of agents, from viruses to parisitic worms, and needs to distinguish them from the organism's own healthy cells and tissues, in order to function properly. Detection is complicated as pathogens can evolve rapidly, producing adaptations that avoid the immune system and allow the pathogens to successfully infect the body. To survive this challenge, multiple mechanisms evolve that recognize and neutralize pathogens. Even simple unicellular organisms such as bacteria possess enzyme systems that protect against viral infections. Humans have a very sophisticated defense mechanisms. The typical vertebrate immune system consists of many types of proteins, cells, organs, and tissues that interact in an elaborate and dynamic network. As part of this more complex immune response, the human immune system adapts over time to recognize specific pathogens more efficiently. This adaptation process is referred to as "adaptive immunity" or "acquired immunity". Disorders in the immune system can result in disease. Immunodefiency occurs when the immune system is less active than normal,...
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