Transfusion Science

Question 1

what is the red cell membrane composed of?

Answer 1

lipid, protein and a small amount of carbohydrate (glycolipids, glycoprotein)

Question 2

what gives the red cell membrane a net negative charge?

Answer 2

the glycoproteins

Question 3

what macromolecule are the ABO, Lewis and H antigens associated with?

Answer 3

carbohydrate

Question 4

what membrane structure are the Rh, Kelly, Duffy and Kidd antigens associated with?

Answer 4

glycoprotein

Question 5

what chromosome is the ABO genes on?

Answer 5

chromosome 9

Question 6

what chromosome is the Rh gene on?

Answer 6

chromosome 1

Question 7

what blood group system has the most antigen sites per red cell?

Answer 7

ABO

Question 8

what blood group system has the least antigen sites per red cell?

Answer 8

Kell system

Question 9

are more antigen sites present on homozygote or heterozygote individuals?

Answer 9

homozygote

Question 10

what are antibodies?

Answer 10

proteins that are produced when a foreign antigenic structure is recognized by the immune system

Question 11

what is an epitope?

Answer 11

the part of the antigen recognised by the immune system

Question 12

what does the primary immune response produce?

Answer 12

IgM antibodies, slower

Question 13

what does the secondary immune response produce?

Answer 13

IgG antibodies, faster

Question 14

what causes the production of antibodies?

Answer 14

1. environmental antigens- bacteria or viruses

2. rbc antigens- blood transfusion or pregnancy

Question 15

what are the light chain classes?

Answer 15

kappa and lambda

Question 16

what are the heavy chain classes?

Answer 16

mu, gamma, alpha, delta, epsilon

Question 17

what part of the antibody anchors it to the surface of cells?

Answer 17

the constant regions

Question 18

what Ig can cross the placenta?

Answer 18

IgG

Question 19

How is the diversity of the immune system acheived?

Answer 19

by genetic recombination

Question 20

what is K the affinity constant?

Answer 20

a measure of the sum of variety of weak non covalent interactions between the antigen and antibody

Question 21

what forces enable antigen antibody binding

Answer 21

Ionic, van der Waals, Hydrogen, hydrophobic bonds

Question 22

what are the stages in haemagglutination?

Answer 22

sensitisation: antibodies attach to antigen
agglutination: intracellular bridges form a lattice of adjacent cells

Question 23

what factors affect sensitsation?

Answer 23

temperature, incubation time, ionic strength, pH

Question 24

what are the cold reacting antibodies?

Answer 24

ABO, Lewis

Question 25

what are the warm reacting antibodies?

Answer 25

Rh, Kell, Duffy and Kidd

Question 26

what does lowering the ionic strength of a medium do?

Answer 26

speeds up the rate of association between antibody and antigen and increasing K value

Question 27

what factors affect in vitro agglutination?

Answer 27

electrical charge, characteristics of antibody, proximity of cells, location of antigen sites, concentration of antibody

Question 28

what is zeta potential?

Answer 28

the difference in potential expressed at the boundary of shear (edge of electron cloud)

Question 29

what charge are red cells?

Answer 29

negative due to sialic acid residues

Question 30

what does high zeta potential do?

Answer 30

prevents agglutination

Question 31

what neutralizes the red cell charge?

Answer 31

papain, trypsin, bromelin, ficin

Question 32

causes of agglutination

Answer 32

centrifugation, proteolytic enzymes, polymers, AHG

Question 33

what causes direct agglutination?

Answer 33

IgM antibodies are large enough to span the gap between cells - ABO blood grouping

Question 34

what causes indirect agglutination?

Answer 34

IgG antibodies, require AHG or enzymes to bridge the gap as IgG is too small

Question 35

who described the first ABO blood group system?

Answer 35

Karl Landsteiner in 1901

Question 36

are ABO antibodies IgM or IgG?

Answer 36

IgM

Question 37

how do the ABO antibodies cause intravascular hemolysis of incompatible cells?

Answer 37

complement activation

Question 38

where is the ABO locus on genes?

Answer 38

chromosome 9

Question 39

where is the H and Se locus on genes?

Answer 39

chromosome 19

Question 40

what does a-2-fucosyltransferase do?

Answer 40

converts a precursor oligosaccharide chain by the addition of fucose to H antigen

Question 41

will a homozygous h allele form the H antigen?

Answer 41

no - doesnt encode transferase

Question 42

what do the H,A,B genes encode for the production of?

Answer 42

transferase enzymes

Question 43

what blood type has the most H antigen present?

Answer 43

O

Question 44

is H antigen present on bombay cells?

Answer 44

no

Question 45

what is the difference between A1 and A2 individuals?

Answer 45

A1 and A1B have more antigen sites than A2/A2B | A1 has A and A1 antigen, A2 only A

Question 46

what antibodies does bombay individuals have in serum?

Answer 46

antiA, antiB and anti H

Question 47

what stimulates ABO antibodies?

Answer 47

environmental antigens - bacteria and viruses

Question 48

when do ABO antibodies form?

Answer 48

3-6 months after birth

Question 49

when are ABH antigens expressed weakly?

Answer 49

patients with leukaemia

Question 50

when does group A individual acquire B antigen?

Answer 50

with gastrointestinal cancer and bacterial infections