Module 11: Adaptive Immunity

• adaptive immunity: response to pathogen is initially weak, increases over time
• what are the 2 components of the adaptive immune system?

  1. antibody immunity: antibodies
  2. cell mediated immunity: group of cells attack pathogens
• what are the 3 features of adaptive immunity in lymphocytes?

  1. tolerance: ignore self-antigens
  2. specificity: reacts to one antigen
  3. memory: remembers pathogen to remove
• what are the 3 antigen presenting cells?

  1. macrophages
  2. dendritic cells
  3. B cells
• dendritic cells: first to detect pathogens and activate immune system
• what is lymph nodes role in adaptive immune response?


  capture antigens from epithelium and connective tissue
• what is the spleens role in adaptive immune response?


  captures antigen from the blood
• what are B cells role in the adaptive immune response?


  recognize antigen directly
• whare are T cells role in adaptive immune response?

  recognize by antigen presenting cells
• B lymphocytes: membrane bound antibodies are antigen receptors
• what is activation of B lymphocytes?

  • antigen binding causes receptors to cluster
  • activates signaling cascade and genes
• what are the differentiation cells of B lymphocytes?

  • plasma cells make antibodies
  • memory cells recognize antigen
• what happens during maturation in B lymphocytes?

  • mature in bone marrow and MALT
  • travel in bloodstream to tissues
• what are the 2 regions in antibodies?

  • variable region: reacts with antigen
  • constant region: interacts with immune system
• which chain defines the antibody type?


  heavy
• igM antibody properties:

  • primary response
  • activates complement cascade
  • B-cell receptor
• igG antibody properties:

  • secondary response
  • crosses placenta
  • activates complement cascade
  • main blood antibody
• igA antibody properties:

  • secreted into mucus, tears, saliva and colostrum
• igE antibody properties:

  • allergy and antiparasitic activity
• igD antibody properties:

  • B-cell receptor
• antibody binding induces complement cascade
• what are the 4 antibody reactions?

  1. agglutination
  2. toxin neutralization
  3. opsonization
  4. steric hindrance
• agglutination: clumps pathogens to be targeted by immune system
• toxin neutralization: antibody binds to toxins
• opsonization: help phagocytes ingest target
• steric hindrance: prevent pathogen binding or attachment
• primary antibody response: slow and weak, takes 14 days to be effective
• secondary antibody response: rapid and strong
• clonal expansion occurs when antigen is encountered by T and B cells
• T lymphocytes: regulate immune system and manage infected host cells
• how are T-cell receptors the same as antibodies?


  have variable and conserved region
• how are T-cell receptors different from antibodies?

  respond to antigen when antigen-presenting cells place in MHC
• MHC 1 molecules: found on almost all cells, signal health of cell
• how are MHC 1 molecules produced?

  1. bind to peptides inside cell
  2. host machinery digests
  3. present to surface for immune system
• MHC 2 molecules: found on antigen presenting cellls, bind to antigens from outside the cells
• CD4+ T cells: immune system regulators
• TH1: recruit and regulate cells for cell mediated immunity (T cell response)
• TH2: regulate B cells and antibody production
• T suppressor cells: turn down immune system after pathogen is dealt with
• CD8+ T cells: T cytotoxic cells, activated by antigen presenting cells