Chapter 57

Summary		Questions		Media Resources
57.1 Many of the body's most effective defenses are nonspecific.
• Nonspecific defenses include physical barriers such as the skin as well as phagocytic cells, killer cells, and complement proteins. • The inflammatory response aids the mobilization of defensive cells at infected sites.		1.  How do macrophages destroy foreign cells? 2.  How does the complement system participate in defense against infection?		•Complement Proteins •Antiviral Defense •Fever •Lymph System •Nonspecific Immunity •Activity: Complement •Immune System
57.2 Specific immune defenses require the recognition of antigens.
• Lymphocytes called B cells secrete antibodies and produce the humoral response; lymphocytes called T cells are responsible for cell-mediated immunity.		3.  On what types of cells are the two classes of MHC proteins found?		•Vaccination •Specific Immunity •Integration of Science and People •Improving Antibodies
57.3 T cells organize attacks against invading microbes.
• T cells only respond to antigens presented to them by macrophages or other antigen-presenting cells together with MHC proteins. • Cytotoxic T cells kill cells that have foreign antigens presented together with MHC-I proteins.		4.  In what two ways do macrophages activate helper T cells? How do helper T cells stimulate the proliferation of cytotoxic T cells?		•T-cell Function •Activity: Killer T cell •Activation of T Cells
57.4 B cells label specific cells for destruction.
• The antibody molecules consist of two heavy and two light polypeptide regions arranged like a "Y"; the ends of the two arms bind to antigens. • An individual can produce a tremendous variety of different antibodies because the genes which produce those antibodies recombine extensively. • Active immunity occurs when an individual gains immunity by prior exposure to a pathogen; passive immunity is produced by the transfer of antibodies from one individual to another.		5.  How do IgM and IgG antibodies differ in triggering destruction of infected cells? 6.  How does the clonal selection model help to explain active immunity? 7.  How are lymphocytes able to produce millions of different types of immune receptors?		•Clonal Selection •Activity: Plasma Cell Production •Integrating Cellular Specificity and Genetic Control of the Immune System •Reptilian Immune System •Monoclonal Antibody Production
57.5 All animals exhibit nonspecific immune response but specific ones evolved in vertebrates.
• The immune system evolved in animals from a strictly nonspecific immune response in invertebrates to the two-part immune defense found in mammals.		8.  Compare insect and mammalian immune defenses.		•Phagocytic Cells •Immune System Evolution
57.6 The immune system can be defeated.
• Flu viruses, trypanosomes, and the protozoan that causes malaria are able to evade the immune system by mutating the genes that produce their surface antigens. In autoimmune diseases, the immune system targets the body's own antigens.		9.  How does HIV defeat human immune defenses? 10.  What might cause an immune attack of self antigens?		•Abnormalities •HIV/AIDS Epidemic •Allergic Reaction

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