chapter 18B - Natural Defenses against Disease 18 Specific...

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18 Natural Defenses against Disease
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18 Specific Defenses: The Immune System Several questions arise that are fundamental to understanding the immune system. How do B and T cells specific to antigens proliferate? Why don’t antibodies and T cells attack and destroy our own bodies? How can the memory of post-exposure be explained? How does the enormous diversity of B cells and T cells arise?
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18 Figure 18.7 Clonal Selection in B Cells
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18 Specific Defenses: The Immune System When the body encounters an antigen for the first time, a primary immune response is activated. When the antigen appears again, a secondary immune response occurs. This response is much more rapid, because of immunological memory.
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18 Immunological memory plays roles in both natural immunity and artificial immunity based on vaccination. Specific Defenses: The Immune System
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18 Specific Defenses: The Immune System Artificial immunity is acquired by the introduction of antigenic determinants into the body. Vaccination is inoculation with whole pathogens that have been modified so they cannot cause disease. Immunization is inoculation with antigenic proteins, pathogen fragments, or other molecular antigens. Immunization and vaccination initiate a primary immune response that generates memory cells without making the person ill.
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18 Specific Defenses: The Immune System Antigens used for immunization or vaccination must be processed so that they will provoke an immune response but not cause disease. There are three principle ways to do this: Attenuation involves reducing the toxicity of the antigenic molecule or organism. Biotechnology can produce antigenic fragments that activate lymphocytes but do not have the harmful part of the protein toxin. DNA vaccines are being developed that will introduce a gene encoding an antigen into the body.
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18 CPS Question An individual exposed to a pathogen for the first time will exhibit an innate immune response involving: A. B lymphocytes B. T lymphocytes C. Granulocytes D. An individual exposed to a pathogen for the first time must acquire immunity before it can respond.
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chapter 18B - Natural Defenses against Disease 18 Specific...

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