IC6

Question 1

nomenclature for immunoassays

Answer 1

anti - (source of antigen) (antigen) (source of antibody) antibody

Question 2

principle of solid phase enzyme immunoassay

Answer 2

1) antibodies immobilised on solid surface -> incubate with enzyme-linked antigen + sample containing antigen
2) competitive binding between enzyme-linked & unlinked antigens w antibodies
3) wash away unbound antigens w buffer solution (phosphate buffered saline PBS) -> add enzyme substrate -> measure absorbance of coloured product formed -> added enzyme substrate

** greater amt of antigen = less enzyme-linked antigen bind = less enzyme activity detected = lower absorbance

Question 3

solid phase enzyme immunoassay - types of ELISA - direct

Answer 3

Ag (pt sample) fix onto solid surface -> washing -> primary antibody (enzyme linked) -> washing -> add substrate -> coloured product -> absorbance

Question 4

solid phase enzyme immunoassay - types of ELISA - indirect - process

Answer 4

Ag (pt sample) fixed onto solid surface -> washing -> primary antibody X enzyme linked -> wash -> secondary enzyme linked antibody 0> Add substrate -> coloured product -> absorbance

Question 5

solid phase enzyme immunoassay - types of ELISA - indirect - advantages

Answer 5

• more accurate results because dependent on 2 antibodies

Question 6

solid phase enzyme immunoassay - types of ELISA - indirect - disadvantages

Answer 6

more expensive

Question 7

solid phase enzyme immunoassay - types of ELISA - sandwhich

Answer 7

lab developed antibody fixed onto solid surface -> add patient sample -> washing -> secondary antibody -> washing -> final enzyme-linked antibody (recognise Fc domain of secondary antibody) -> washing -> add substrate -> coloured product

Question 8

solid phase enzyme immunoassay - types of ELISA - competitive

Answer 8

captured antibody immobilised on solid surface -> co-incubate w antigen from pt sample + fixed amount of lab developed enzyme-linked antigen -> washing -> susbtrate -> coloured product

Question 9

advantages of solid phase enzyme immunoassay

Answer 9

1) specific & sensitive: quantitative/semi-quantitative/qualitative

2) easy to use

3) safe to use

Question 10

blood type and antibodies/antigens

Answer 10

1) blood type A
- antigen A antibody B

2) blood type B
- antigen B antibody A

3) blood type O
- antigen A, B, no antibody

4) blood type AB
- no antigen, antibody A, B

Question 11

requirement for agglutination

Answer 11

antigen +/- antibody that is particulate in nature (semi-solid/solid by conjugation to solid particle)

Question 12

passive/direct haemaglutination

Answer 12

antibody + antigen -> agglutinate -> visual change

Question 12

inhibition haemaglutination

Answer 12

1) antibody + known amount of agglutinator -> agglutination

2) add sample antigens
- sample higher affinity for antibody than agglutinator -> displace agglutinator from antibody -> lesser agglutination -> less turbidity

Question 12

quantifying vs qualifying inhibition agglutinator

Answer 12

1) quantifying
- more antigen in pt sample = more able to competitively bind = displace more agglutinator = lesser visual change

2) qualifying
- look different from positive control = qualitative