Defence against Diseases - Monoclonal antibodies

Question 1

what are monoclonal antibodies and how do they work

Answer 1

• 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

Question 2

describe the stages in which mAB’s are produced

Answer 2

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

Question 3

advantages of mABs

Answer 3

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

Question 4

what can mABs be used in

Answer 4

• 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

Question 5

disadvantages of mAB’s

Answer 5

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

Question 6

what hormone is found in pregnant women

Answer 6

HCG

Question 7

how do pregnancy kits work

Answer 7

• 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

Question 8

what does the 1st test window show

Answer 8

the test result - coloured line = pregnancy

Question 9

what does the 2nd window show

Answer 9

if the test is working