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White blood cells, including B lymphocytes, protect against pathogens. Innate immunity is nonspecific, while adaptive immunity involves B lymphocytes producing antibodies specific to antigens. Plasma cells secrete antibodies, while memory cells provide continued immunity. Vaccines activate adaptive immune responses to produce immunity without causing disease.
White blood cells are the main protectors of the human body, working against infectious pathogens such as viruses, fungi and bacteria. B lymphocytes, one of several types of white blood cells, are involved in a specific type of adaptive immunity necessary for the antibody response. During the early stages of development, B-cell production begins in the fetus in the liver and later occurs in the bone marrow.
Immunity is achieved in two main ways: it is either innate or acquired which is also referred to as adaptive immunity. Innate immunity is a nonspecific form of defense that everyone is born with, including chemical responses, barrier structures such as skin and mucous membranes, and the host of microorganisms that reside in the body, called the normal flora. Some harmful pathogens manage to overcome these natural barriers, in which case adaptive immune responses are triggered, with B lymphocytes playing a significant role. Humoral immunity is an adaptive mechanism of specific immunity involving the formation of antibodies, which are proteins that bind to antigens produced by foreign invaders.
Responsible for the production of antibodies, B lymphocytes, with the assistance of helper T cells, become activated after recognizing a specific antigen and bind to receptors on its surface. Then they divide into identical b-cell clones. Each cloned b-cell produces antibodies specific to the particular antigen responsible for activating the b-cell of origin. From this point, the B lymphocytes differentiate as plasma cells or will become memory cells.
Permanently stationed in the lymph nodes until cell death, a plasma cell’s job is to secrete antibodies, which travel to the blood and lymph nodes, destined for the site of infection. By providing continued immunity even after the infection has cleared, memory cells do not succumb to apoptosis or programmed cell death, as plasma cells do. Memory B cells have an activated gene inside them, which allows them to live longer, so that if the particular microbe tries to attack again later, the response will be quicker.
Immunization provides an artificial means to develop continued active immunity, which occurs following exposure to antigen through the administration of a vaccine. Once a vaccine is administered, adaptive immune responses are activated, producing b-cell clones, antibodies, plasma cells, and memory cells. Developed to induce immunity without causing actual disease, vaccines are made from pathogens that have been altered in some way or killed off. Proteins of pathogens are also used in the formulation of vaccines.
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