Week 14

• Genes (Cell Surfaces)


  Encode antibodies and cell surface antigens

  
  

  Encode the 6-million-base-long DNA sequence on the short arm of chromosome 6, known as the Major Histocompatibility Complex (MHC) - confers about 50% of the genetic influence on immunity
• Blood Typing (Cell Surfaces)


  It is done according to the surface antigens in RBCs
• Antibodies


  They are proteins that directly attack foreign antigens, which are any molecules that can elicit an immune response. Most antigens are proteins or carbohydrates. Genes also specify the cell surface antigens that mark the body's cells as "self."
• MHC Class III


  Encode proteins in the plasma which provide immune functions
• MHC Classes I and II


  Encode human leukocyte antigens (HLA)
• HLA Glycoproteins


  Bind bacterial and viral proteins in such a way that will alert other immune system cells
• Class I HLA


  6 genes = 3 genes found in all cell types + 3 genes with more restricted distribution
• Class II HLA


  3 major genes found mostly on antigen-presentinig cells
• Ankylosing Spondylitis


  Resulting from two subtypes of HLA B27
• Innate Immune Response (Human Immune System)


  Immediate, generalized
• Adaptive Immune Response (Human Immune System)


  Slower, specific
• Inflammation (Human Immune System)


  The process of creating a hostile environment for pathogens at an injury site
• Complement (Innate Immunity)


  Consists of plasma proteins which assist several other defenses
• Collectins (Innate Immunity)


  Protect against bacteria, fungi, and some viruses by detecting differences in their cell surfaces
• Interferons (Cytokines)


  Alerts components of the immune system to the presence of infected cells

  
  

  Block viral replication, stimulate macrophages to engulf viruses, stimulate B cells to produce antibodies, attack cancer cells
• Interleukins (Cytokines)


  Cause fever, which directly kills or inhibits the growth some infecting bacteria and viruses

  
  

  Control lymphocyte differentiation and growth, cause fever that accompanies bacterial infection
• Higher Body Temperature


  Directly kills some infecting bacteria and viruses. Fever also counters microbial growth indirectly, because ______________ reduces the iron level in the blood.
• Adaptive Immunity


  B Cells carry out the humoral immune response which produces antibodies

  
  

  T Cells carry out the cellular (or cell-mediated) immune response which produces cytokines

  
  

  B and T Cells differentiate in the bone marrow, and migrate to the lymph nodes, spleen, and the thymus, and circulate in the blood and tissue fluid
• Diverse (Adaptive Immunity)


  Can tackle various types of pathogens
• Specific (Adaptive Immunity)


  Distinguishes "self" from "non-self"
• Remembers (Adaptive Immunity)


  Responds faster to a previous infection; primary and secondary immune responses
• Humoral Immune Response


  Macrophage activates a T cell -> T cell contracts a B cell with surface receptors that can bind the antigen presented by the macrophage -> T cell releases cytokines that stimulate B cells to divide -> B cells give rise to plasma cells and memory cells
• Plasma Cells


  First, antibody factories, each secreting 1,000 to 2,000 identical antibodies per second into the bloodstream. ___________ live only days. These cells provide the primary immune response. ___________ derived from different B cells secrete different antibodies. Each type of antibody corresponds to a specific part of the pathogen, like hitting a person in dif- ferent parts of the body.
• Polyclonal Antibody Response


  What do you call to the multi-pronged attack of the plasma cells?
• Memory Cells


  The second type of B cell descendant, are far fewer and usually dormant. They respond to the foreign antigen faster and with more force should it appear again. This is a secondary immune response. They are what enabled survivors of the 1918 flu pandemic to resist infection.
• Y-Shaped Antibody Subunit (Antibody Structure)


  The two longer polypep- tides are called heavy chains, and the other two light chains. The lower portion of each chain is an amino acid sequence that is very similar in all antibody molecules, even in different spe- cies. These areas are called constant regions, and they provide the activity of the antibody. The amino acid sequences of the upper portions of each polypeptide chain, the variable regions, can differ greatly among antibodies. These parts provide the specificities of particular antibodies to particular antigens.
• Idiotypes (Antibody Structure)


  The parts that contact the antigen on antigen binding sites are called?
• Epitopes (Antibody Structure)


  The parts of the antigen that bind to the idiotypes are called?
• Neutralization, Inactivation, Clumping of Pathogens for removal of phagocytes (Opsonization), and Activation of the complement system


  What are the several functions of Antibodies?
• Chromosome 14 (Genetics of Antibody Assembly)


  Variable region genes (V, D, and J) for the heavy chains are on?
• Chromosome 2 and 22


  Variable region genes for the light chains are found on?
• Antibody Diversity (Genetics of Antibody Assembly)


  The human immune system can produce antibodies to millions of possible antigens because each polypeptide is encoded by more than one gene. That is, the many components of antibodies can combine in many ways.
• IgA (Types of Antibodies)


  Milk, Saliva, urine, and tears; respiratory and digestive secretions (Location)

  
  

  Protects against pathogens at points of entry into body (Functions)
• IgD (Types of Antibodies)


  On B cells in blood (Location)

  
  

  Stimulates B cells to make other types of antibodies, particularly in infants (Functions)
• IgE (Types of Antibodies)


  In secretions with IgA and in mast cells in tissues

  
  

  Acts as receptor for antigens that cause mast cells to secrete allergy mediators (Functions)
• IgG (Types of Antibodies)


  Blood plasma and tissue fluid; passes to fetus (Location)

  
  

  Protects against bacteria, viruses, and toxins, especially in secondary immune response (Functions)
• IgM (Types of Antibodies)


  Blood plasma (Location)

  
  

  Fights bacteria in primary immune response; includes anti-A and anti-B antibodies of ABO blood groups
• Cellular Immune Response: The T Cell Maturation Process


  T cells descend from stem cells to the bone marrow -> Travels to thymus gland -> Thymocytes (immature T cells) approach the lining of the thymus gland, which are studded with "self" antigens -> Thymocytes which do not attack these cells mature into T cells, while those who harm the lining die by apoptosis
• Helper T Cells (T Cell Types)


  Recognize foreign antigens, stimulate B cells to produce antibodies, secrete cytokines, activate cytotoxic T cells (has CD4 receptors)
• Cytotoxic T Cells (T Cell Types)


  Binds to antigens and releases perforin, which kills the cell membrane of the "nonself" cell (has CD8 receptors)