Chapter 20 Outline (edited by Cang Nguyen on Ultimeaciax-NB @ 1-17-2007 3-11-00 PM)

Chapter 20 Outline (edited by Cang Nguyen on Ultimeaciax-NB @ 1-17-2007 3-11-00 PM)

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Chapter 20 Resistance and the Immune System: Acquired Immunity Introduction 20.1 An Overview of the Acquired Immune Response The Ability to Eliminate Pathogens Requires a Multifaceted Approach o Antigens are microbes or microbe parts that provoke an immune response o The immune systems recognizes unique antigenic determinants (epitopes) o Immune deficiency is the loss of the body’s ability to respond to antigens and epitopes o Regulatory T cells prevent other T cells from attacking “self” cells Autoimmune diseases occur when self-tolerance breaks down o If nonimmunogenic molecules (haptens) are linked to proteins, they may not be recognized as “self” and provoke an immune response (allergies) o Immunological memory is the ability to “remember” past pathogen exposures so the body fights off any subsequent infections Acquired Immunity Generates Two Complementary Responses to Most Pathogens o B lymphocytes (B cells) are involved in producing antibodies against epitopes o T lymphocytes (T cells) provide resistance through lysis of infected or abnormal cells o The humoral immune response involves activation of B cells and production of antibodies against the identified antigen o If the microbes enter cells, antibodies are useless, so the cell mediated immune response is activated to eliminate “nonself” cells Clonal Selection Activates the Appropriate B and T Cells o Antigen exposure activates only T and B cells with receptors that recognize specific epitopes on that antigen o Stimulated B and T cells divide to form clones – a population of genetically identical B cells o B and T cell clones contain lymphocytes that develop into: Effector cells, such as plasma cells, which target pathogens
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Chapter 20 Outline (edited by Cang Nguyen on Ultimeaciax-NB @ 1-17-2007 3-11-00 PM)

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