module 4 - 12.6 the specific immune system Flashcards
how is the specific immune system different to non-specific responses?
- specific immune system is slower than non-specific
- immune memory cells react much quicker if second invasion of same pathogen occurs
what are antibodies?
Y-shaped glycoproteins called immunoglobulins which bind to specific antigen on pathogen/toxin that has triggered immune response
what are antibodies made up of?
- 2 identical polypeptide chains - heavy chains
- 2 shorter identical chains - light chains
- chains are held together by disulphide bridges & disulphide bridges within polypeptide holding its shape
why is the binding site known as the variable region?
- binding site is area of 110 amino acids on both heavy and light chains
- different shape on each antibody - specificity
why is the rest called the constant region?
rest of antibody molecule is always the same
what is formed when an antibody binds to antigen?
antigen-antibody complex
how do antibodies defend the body?
- antibody of antigen-antibody complex acts as opsonin so complex is easily engulfed & digested by phagocytes
- most pathogens cant invade hist cells once part of complex
- antibodies act as agglutinins, cause pathogens carrying complexes to clump together - helps prevent them spreading through body
- antibodies can act as anti-toxins, binding to the toxins produced by pathogens
which white blood cells are involved in the immune response?
- B lymphocytes - mature in bone marrow
- T lymphocytes - mature in thymus gland
what are the main types of T lymphocytes?
- T helper cells
- T killer cells
- T memory cells
- T regulator/suppressor cells
what are T helper cells?
- have receptors on cell-surface membranes what bind to surface antigens
- produce interleukins - stimulate activity of B cells, increasing antibody production, attracts and stimulates macrophages
what are T killer cells?
- destroy pathogens carrying antigen
- produce chemical called perforin - kills pathogen by making holes in cell membrane so is freely permeable
what are T memory cells?
- live for long time, part of immunological memory
- if they meet antigen a second time, they divide rapidly to form a huge number of T killer cells and destroy pathogen
what are T regulator/suppressor cells?
- suppress immune system, control & regulate it
- stops immune response once pathogen has been eliminated
- makes sure body recognises self-antigens and doesn’t set up autoimmune response
what are the main types of B lymphocytes?
- plasma cells
- B effector cells
- B memory cells
what are plasma cells?
they produce antibodies to particular antigen and them release into circulation
what are B effector cells?
they divide to form the plasma clones
what are B memory cells?
- provide immunological memory
- programmed to remember specific antigen & enable body to make rapid response when pathogen carrying that antigen is encountered again
what happens during cell-mediated immunity?
(happens inside cells) - T lymphocytes respond to the cells of an organism that have been changed by antigen processing or by mutation
what is the first stage of cell mediated immunity?
- in non-specific defence system, macrophages engulf & digest pathogens in phagocytosis
- they process antigens from surface of pathogen to form antigen-presenting cells
what is the second stage of cell mediated immunity?
- receptors in some of the T helper cells fit the antigens
- T helper cells are activated & produce interleukins - stimulate more T helper cells to divide (mitosis)
- form clones of identical activated T cells that carry correct antigen to bind to pathogen
what 4 things may the clones T cells do
- develop T memory cells which give rapid response if pathogen invades body again
- produce interleukins that stimulate phagocytosis
- produce interleukins that stimulate B cells to divide
- stimulate development of clone T killer cells, specific for presented antigen then destroy infected cells
what happens during humoral immunity?
body responds to antigens found outside the cells
- humoral immune system produces antibodies that are soluble in blood and tissue fluid & are not attached to cells
where do B lymphocytes have antibodies?
on cell surface membrane
what happens when a pathogen enters the body?
- carries specific antigens
- produces toxins that act as antigens
- B cell with complemetary antibodies will bind to antigens on pathogen or free antigens
what are the stages of humoral immunity?
- activated T helper cells bind to B cell - clonal selection
- interleukins produced by activated T helper cells activate the B cells
- activated B cell divides by mitosis, give clones of plasma & B memory cells - clonal expansion
- cloned plasma cells produce antibodies that fit antigens on surface of pathogen, bind to antigens and disable them - primary immune response
- some cloned B cells develop into B memory cells, is body infected by same pathogen again, memory B cells divide rapidly to form plasma cell clones - secondary immune response
what is an autoimmune disease?
immune system stops recognising ‘self’ cells and starts to attack healthy body tissue
what treatments are there for autoimmune diseases?
immunosuppressant drugs which prevent immune system working, may be used as treatments
which part of the body is affected by Type 1 diabetes?
insulin secreting cells of the pancreas
how is type 1 diabetes treated?
- insulin injections
- pancreas transplants
- immunosupressant drugs
which part of the body is affected by Rheumatoid arthritis?
joints
what treatment is there for rheumatoid arthritis?
- no cure
- anti-inflammatory drugs
- steroids
- pain relief
what part of the body is affected by lupus?
- skin and joints and causes fatigue
- can attack any organ in the body
what treatment is there for lupus?
- no cure
- anti-inflammatory drugs
- steroids
