Intro to Transfusion Science

Question 1

Definition of antigen

Answer 1

Any substance/structure that when introduced to an individual who lacks the antigen stimulates an immune response which results in the production of an antibody that is capable of reacting specifically with the antigen in some observable way

Question 2

Definition of antibody

Answer 2

A protein which appears in plasma and body fluids as a result of stimulation by an antigen and will react specifically with that antigen in some observable way

Question 3

In an antibody, what is contained within the variable region

Answer 3

Antigen combining bonds. Sequences of amino acids that will bind with a specific antigen.

Question 4

IgM shape

Answer 4

Pentamer

Question 5

IgG shape

Answer 5

Monomer

Question 6

What links heavy chain and light chain domains in antibodies

Answer 6

Disulphide bridges

Question 7

IgG vs IgM in terms of:
Placental Transfer
Opt rxn temp
Primary immune response involvement
Secondary immune response involvement

Answer 7

Placental transfer: IgG: Yes IgM: No
Optimum reaction temperature: IgG: 37°C IgM: 4°C - 20°C
Primary immune response involvement: IgG: Rare IgM: Yes
Secondary immune response involvement: IgG: Yes IgM: Rare

Question 8

Possible genotypes for blood group A

Answer 8

A/A or A/O

Question 9

Possible genotypes for blood group B

Answer 9

B/B or B/O

Question 10

Possible genotypes for blood group AB

Answer 10

A/B

Question 11

Possible genotypes for blood group O

Answer 11

O/O

Question 12

Explain the two-locus theory

Answer 12

• One locus carries the Rh
  D gene
• Second closely linked
  locus carries the
  Cc/Ee gene
• C and c are antithetical
  genes
• E and e are antithetical
  genes
  Genes are considered antithetical when a protein can only express one of them.

Question 13

What is cell grouping/ forward grouping

Answer 13

The test to determine the ABO group of a patient or blood donor. The presence or absence of A and B antigens must be detected on the red cells and this is referred to as cell/forward grouping.

Question 14

What is serum/reverse grouping

Answer 14

The detection of the corresponding antibodies of the ABO system in the plasma or serum of a patient or donor.

Question 15

Group A antigen and antibodies

Answer 15

• A antigen on red cells
• Anti B antibodies in plasma

Question 16

Group B antigen and antibodies

Answer 16

• B antigens on red cells
• Anti A antibodies in plasma

Question 17

Group AB antigen and antibodies

Answer 17

• Both A and B antigens on red cells
• No Anti A or Anti Bantibodies in plasma

Question 18

Group O antigen and antibodies

Answer 18

• No A or B antigens on red cells
• Both Anti A and Anti B antibodies in plasma

Question 19

What do the blood grouping antisera contain

Answer 19

Antibodies that will detect specific antigens present on red cells of patients/ donors.

Question 20

What is the rxn between antigen and antibody called

Answer 20

Red blood cell haemagglutination Reaction

Question 21

What will happen with Group A rbcs when added to the anti A grouping antiserum

Answer 21

Group A rbcs have the A antigen on their surfaces and will react (agglutinate) with the Anti A grouping antiserum.

Question 22

What age group is reverse grouping not performed on and why?

Answer 22

4-6 month olds as they have not developed ABO antibodies yet - immune system not fully developed