Medical Intervention Chapter 8 Study Guide

• specific (adaptive) immunity: immunity against a specific antigen or disease
• specific immunity characteristics:

  • not present at birth
  • it is acquired
  • it tailors its attack to a specific antigen previously encountered
  • it takes time for it to develop after initial exposure to new antigens
• as a persons immune system encounters antigens, it learns the best way to attack each antigen and begin to develop memory for that antigen
• the hallmarks of specific immunity:

  • the ability to learn
  • the ability to adapt
  • the ability to remember
• specific immunity involves the following:

  • lymphocytes
  • dendritic cells
  • antibodies
  • cytokines
  • complement system
• lymphocytes:

  • enables the body to remember antigens & to distinguish “self from nonself“
  • circulates in the bloodstream & lymphatic system & move into tissues as needed
• lymphocytes also include:

  • b lymphocytes
  • t lymphocytes
  • natural killer cells
• lymphocytes - most important type of white blood cells thats involved in specific immunity
• lymphocytes - these cells can remember every antigen encountered because they live for a long time
• lymphocytes - when they encounter an antigen a second time, they respond quickly
• dendritic cells:

  • developed from monocytes
  • resides in tissues
  • newly developed ones ingest & break antigens into fragments so that other immune cells can recognize them
• dendritic cells (continued):

  • it matures after it has been stimulated by cytokines at a site of infection or inflammation
  • then it moves from the tissues to the lymph nodes where it presents antigen fragments to T cells, which generate a specific immunological response
• the main function of dendritic cells: to process antigen material and present it on the cell surface to the T cells
• dendritic cells are antigen presenting cells and act as messengers between adaptive & innate immunity
• antibodies (immunoglobulins or Ig):

  • produced when a b cell encounters foreign antigen, which is stimulated to mature into a plasma cell
  • protects the body by helping other immune cells ingest foreign antigen by inactivating toxic substances produced by bacteria & by attacking viruses & bacteria directly
  • helps fight off certain types of bacteria
• Antibodies are a large, Y-shaped protien produced mainly by plasma cells that are used by the immune system to identify + neutralize pathogens such as bacteria + viruses.​
• antibodies are glycoproteins
• glycoproteins: proteins that contain oligosaccharides that are covalentes attached to polypeptide side chains
• each antibody molecule has 3 parts known as:

  • variable region
  • constant region
  • hinge region
• antibodies are made of 4 polypeptide chains or 2 identical heavy chains & 2 identical light chains
• The amino terminal ends of the polypeptide chains show considerable variation in amino acid 

  composition + are referred to as the variable regions to distinguish them from constant regions.
• Each light chain consist of 1 variable domain + 1 constant domai.
• The heavy chains consist of a variable domain + 3 constant domains.
• The heavy + light chains are held together by a combination of 

  non-covalent interactions + covalent interchain | disulfide bonds.
• hinge region: the area of the heavy chains between 

  the first + second constant region domain and is held by disulfide bonds.​
• constant region: determines an antibody’s class
• variable region: consists of a variable domain and three constant domains on the antibody

  molecule
• variable region:

  • varies from antibody to antibody
  • it is specialized to attach to a specific antigen
• constant region:

  • 1 of 5 structures which determines the antibody class
  • antibody classes include: IgG, IgM, IgD, IgA, IgE
• The 5 classes of antibodies are distinguished by the type of heavy chain found in the molecule.
• Differences in heavychain polypeptides allow these molecules to function in different types of immunological responses at particular stages of the immunological system.​
• IgG: 

  • predominant antibody class
  • only antibody class that can cross the placenta in humans
  • largely responsible for protecting the new born during the first month of life 
• IgM:

  • most efficient complement fixing immunoglobulins.
  • the heavy chains are composed of 1 variable + 4 constant regions -> no hinge region.
  • Cell agglutination occurs due to recognition of epitopes on invading microbes
• cell agglutination: when cells clump together forming aggregates.
• epitopes: part of an antigen that is recognized by the immune system specifically by antibodies, B cells or T cells.​
• IgD:

  • a receptor for antigen found in mature B cells.​
• IgA:

  • primary defense mechanism against some local ​infections because of its abundance in saliva & tears
  • prevents the passage of foreign substances into the circulatory system 
• IgE:

  • defends against parasitic invasion.
  • responsible for allergic reactions.​
• cytokines:

  • messengers of the immune system; are produced when an antigen is detected
  • some stimulate certain white blood cells in order to become more effective killers and to attract other white blood cells to a troubled spot (chemotaxis)
  • others inhibit cellular activity to help end an immunological response
  • found in both innate & adaptive immunity
• cytokines are secreted by specific cells of immune system