Defence against Diseases - Monoclonal antibodies Flashcards

1
Q

what are monoclonal antibodies and how do they work

A
  • identical antibodies that are all produced from a single clone of cells, formed from one specific B-Lymphocyte
  • mAB’s are specific to one binding site on one protein antigen + complementary to shape of antigen –> can target a specific chemical or specific cell in the body
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2
Q

describe the stages in which mAB’s are produced

A
  1. mouse is injected with the specific antigen that the scientists want to produce antibodies to
  2. B-Lymphocytes in mouse are stimulated and produce antibodies to the antigen
  3. B-Lymphocytes are extracted from mouse
    4 . B-Lymphocytes are combined with a tumour cell : by adding a detergent to cells to make the cell surface membranes of both the B-Lymphocyte an tumour cell fuse together
  4. the combining of B-Lymphocyte and tumour cell forms a HYBRIDOMA CELL
  5. the hybridoma cell has 2 important characteristics
    • can divide repeatedly to produce genetically identical cells (characteristics of tumour cells)
    • can produce the desired specific antibody
  6. hybridoma cells is then cloned : divides repeatedly making genetically identical copies of itself
  7. each cloned hybridoma cells produces the specific antibodies to the antigen
  8. the antigens are collected + purified
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3
Q

advantages of mABs

A
  • can target any molecule, including humans
  • don’t kill adjacent cells, unlike some anti-cancer drugs
  • can be produced in huge quantities, quickly
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4
Q

what can mABs be used in

A
  • Diagnostic tests - pregnancy tests
  • measure hormone levels
  • detect pathogens in blood
  • locate / identify specific molecules in a cell / tissue by binding to them with fluorescent dye
  • treat some diseases - cancer –> mABs bind to a radioactive substance, toxic drug / chemical which stops cell growth + division –> delivers the substance to the cancer cells without harming other cells in body
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5
Q

disadvantages of mAB’s

A
  • can create more side effects than expected
  • are not as widely used as everyone hoped when they were first developed
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6
Q

what hormone is found in pregnant women

A

HCG

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7
Q

how do pregnancy kits work

A
  • sipstick dippled in early morning urine sample
  • dipstick contains mAB specific for hCG which are mobile
  • mAB have blue dye particle attached (dye- mAB)
  • hCG in urine moves up the strip
  • hCG acts as antigen
  • hCG binds to dye-mAB due to complementary shapes of the hCG to the binding site of the mAB
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8
Q

what does the 1st test window show

A

the test result - coloured line = pregnancy

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9
Q

what does the 2nd window show

A

if the test is working

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10
Q

what process happens at the 1st window

A
  • a second mAB specific for the hCG-dye-mAB complex is immobilised in a test window
  • 1st hCG-dye-mAB complex binds to 2nd mAB –> help in position
  • blue dye accumulates
  • coloured lined indicates pregnancy
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11
Q

what happens at the 2nd test window

A
  • any uncombined antibodies dye-mAB continue to move up the dipstck
  • to a 2nd line of mAB specific antibodies
  • to form a second coloured band that shows strip is working
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12
Q

why are women advised to test with urine after they first wake up after a nights sleep

A

concentration of hCG will be higher –> test more accurate + reliable

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13
Q

what antigen is present in prostate cancer

A

PSA (prostate specific antigeb)

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14
Q

describe the blood test for PSA using monoclonal antibodies

A
  1. Antibodies to PSA bound to bottom of the reaction vessel
  2. blood plasma sample added –> PSA binds to primary antibody
  3. Wash out ( removes any unbound antigens)
  4. Secondary antibody (antibody + enzyme) added –> only binds to Primary antibody if PSA is present
  5. Wash out–> removes any unbound antibodies
  6. substrate added –> enzyme reacts with substrate, forming a coloured product
  7. if enzymes did not bind to primary antibody (PSA not present), then will be rinsed out –> substrate will not react with enzyme –> to colour change –> PSA not present
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