Topic 11

• non-specific immunity


  Ingestion of pathogens by phagocytic white blood cells gives non-specific immunity to disease
• specific immunity


  Production of antibodies by lymphocytes in response to particular pathogens gives specific immunity
• Antigen


  a toxin or other foreign substance that induces an immune response in the body, especially the production of antibodies
• Antibody


  A protein that acts against a specific antigen
• Antigens on the surface of red blood cells stimulate...


  antibody production in a person with a different blood group
• Pathogen


  is an agent that causes disease - either a microorganism (bacteria, protist, fungi or parasite) or virus
• Zoonoses


  Diseases transmitted from animals to humans
• B lymphocytes are activated by


  T lymphocytes
• macrophages


  Non-specific immune cells
• T lymphocytes


  Antigenic fragments are presented to specific helper T lymphocytes (TH cells) that, when activated, releases cytokinesThe cytokines stimulate a specific B cell
• B lymphocytes


  produces antibodies to the antigen to divide and form clones or memory cells and is activated by cytokinesis
• types of t cells


  cytotoxic t cellshelper t cellssuppressor t cellsmemory t cells
• plasma cells


  secrete antibodies
• antibodies aid in


  the destruction of pathogens
• What does a b lymphocyte turn into


  a plasma cell and a memory cell. Plasma cells secrete antibodies. Antibodies aid the destruction of pathogens. Memory cells provide future immunity.
• Memory cells are produced to


  prevent delay in subsequent exposures, preventing disease symptoms from developing
• clonal expansion


  the rapid multiplication of B or T cell clones after activation by an antigen
• immunity depends on


  the persistence of b memory cells
• Histamine


  Chemical stored in mast cells that triggers dilation and increased permeability of capillaries
• mast cells


  Cells that release chemicals (such as histamine) that promote inflammation.
• allergen


  an environmental substance that triggers an immune response despite not being intrinsically harmful
• Steps of a allergic response


  - When a specific B cell first encounters the allergen, it differentiates into plasma cells and makes large quantities of antibody (IgE)- The IgE antibodies attach to mast cells, effectively 'priming' them towards the allergen- Allergens bind to antibodies on the mast cells- Upon re-exposure to the allergen, the IgE-primed mast cells release large amounts of histamine which causes inflammation or an allergic response
• Inflammatory response


  improves leukocytes mobility to infected regions by triggering vasodilation and increasing capillary permeability
• Vasodilation


  the widening of blood vessels to improve the circulation of blood to targeted regions
• Capillary permeability


  the capacity for leukocytes to leave the bloodstream and migrate into the body tissue
• leukocytes


  white blood cells
• Histamine induing allergic symptoms:


  capillary widening, increased permiability, attration of leukocytes, systemic response
• Vaccines contain


  antigens that trigger immunity but do not cause the disease
• Vaccinations induce


  ong-term immunity to specific pathogenic infections by stimulating the production of memory cells
• how does a vaccine work?


  - an injected vaccine by initiating a primary immune response, which results in memory cells being made- When exposed to the actual pathogen, the memory cells trigger a more potent secondary immune response- As a consequence of this more potent immune response, disease symptoms do not develop
• herd immunity


  The resistance of a group to an attack by a disease to which a large proportion of the members of the group are immune
• What disease was eliminated because of vaccine?


  smallpox
• Epidemiology


  is the study of the patterns, causes and effects of health and disease conditions in a defined population
• monoclonal antibodies


  are antibodies artificially derived from a single B cell clone (i.e. identical specific antibodies) / a general antibody
• hybridoma cell


  A cell made by fusing a b lymphocyte and a cancer cell
• monoclonal antibodies are produced by


  hybridoma cells
• Monoclonal antibodies can be used for


  therapeutic treatment and clinical detection of disease
• hCG


  a hormone produced by women during foetal development and thus its presence in urine is indicative of pregnancy
• Monoclonal antibodies can be used to test for pregnancy via


  the presence of human chorionic gonadotrophin (hCG) in urine
• How do pregnancy tests work?


  - Free monoclonal antibodies specific to hCG are conjugated to an enzyme that changes the colour of a dye- A second set of monoclonal antibodies specific to hCG are immobilised to the dye substrate- If hCG is present in urine, it will interact with both sets of monoclonal antibody (forming an antibody 'sandwich')- When both sets of antibody are bound to hCG, the enzyme is brought into physicial proximity with the dye, changing its colour- A third set of monoclonal antibodies will bind any unattached enzyme-linked antibodies, functioning as a control