Lecture 21C - Immunology PDF

General Aspects of Specific or Adaptive Immunity Two characteristics distinguish immunity from nonspecific resistance – Specificity: immunity directed against a particular pathogen – Memory: when re-exposed to the same pathogen, the body reacts so quickly that there is no noticeable illness Forms of...

General Aspects of Specific or Adaptive Immunity Two characteristics distinguish immunity from nonspecific resistance – Specificity: immunity directed against a particular pathogen – Memory: when re-exposed to the same pathogen, the body reacts so quickly that there is no noticeable illness Forms of Immunity Two types of immunity – Cellular (cell-mediated) immunity: T cells Lymphocytes directly attack and destroy foreign cells or diseased host cells Means of ridding the body of pathogens that reside inside human cells, where they are inaccessible to antibodies – Humoral (antibody-mediated) immunity: B cells Mediated by antibodies that indirectly destroy a pathogen Can only work against the extracellular stage of infectious microorganisms Classes of Humoral Immunity Active vs passive emon > has - – Active: the body makes it’s own antibodies forever Taken– Passive: acquire them from another source memory& no ↳ ↑ from se ↳ temporary someoneNatural vs artificial – Natural: exposure to a pathogen – Artificial: introduced for treatment/prevention Four classes: – – – – ↳ via needle of ceep Majority or Natural active Artificial active Vaccine Datogen Natural passive meRosean Artificial passive Inject : -> keep : dies · · you wy antibodies from someone else ↳ antibodies already made - don't keep Classes of Humoral Immunity Antigens Antigen → any molecule that triggers an immune response – Large molecular weights of over 10,000 amu – Proteins, polysaccharides, glycoproteins, glycolipids Epitopes (antigenic determinants) – Specific regions that stimulate immune responses Self antigens – MHC proteins (Major Histocompatibility Complex) Cells of the Adaptive System - Lymphocytes Cells of the Adaptive System - APCs Antigen presenting cells (APCs) that present antigens to T cells – Dendritic cells – at the body’s surface; start an immune reaction – Macrophages – want activated – B cells – want activated