BLOOD BANKING
Prepared by:
JOSEPHINE C. MILAN, RMT, MSMT
DEPARTMENT OF MEDICAL LABORATORY
TECHNOLOGY
UNIVERSITY OF TABUK
OBJECTIVE and FOCUS
 To correlate the structure of the red
cell membrane with the occurrence of
blood group antigens and how it is
influenced by storage conditions.
RATIONALE
 Q: WHY DO WE STUDY THIS TOPIC ?
 The main purpose of blood transfusion is to supply red
cells which should remain viable and functional in the
transfused patient/ recipient.
 We have to understand the nature of RC membranes.
 Mainly, blood groups antigens are located in /on the
red cell membranes. The structure of the red cell
membranes has certain roles for its functionality.
There are important things to remember about the
characteristics of red cell membranes.
TOPIC OUTLINE (based on syllabus)
 1. Red cell membrane structure
 2. Blood group antigens on the red cell membrane
 3. Other properties of the red cell membrane
 Main reference: Modern Blood Banking and
Transfusion Practices by Denise M. Harmening. F.A.
Davis Company. Philadelphia 5th ed
RED CELL FUNCTION
Main function of red cells:
 To transport
oxygen to tissues, and bind carbon dioxide
from tissues to be brought to the lungs for excretion.
Important for RBC survival and function:
1. normal chemical composition and structure of the RBC
membrane
2. hemoglobin structure and function
3. RBC metabolism
RED CELL MEMBRANE STRUCTURE
RBC Membrane:
RBC membrane is a semipermeable lipid
1.bilayer
supported by a protein meshlike
cytoskeleton structure.
2 layer of lipids
proteins
RED CELL MEMBRANE STRUCTURE
RED CELL MEMBRANE STRUCTURE
 2.
Behaves as semisolid, with elastic and viscous
properties
  important
and critical for survival in the
circulation for 120 days going through numerous
cycles and passages through narrow veins and
sinusoids in the spleen.
  in RBC deformability and permeability (crucial /
critical characteristics)
Biochemical structure
3. The cell membrane consists of :
protein,
lipids, and
carbohydrates
52 (P) :
Ratio of-
40 (L)
:
8 (C)
PROTEINS IN THE MEMBRANE
Proteins : form a meshwork that traverse the lipid
bilayer, called membrane skeleton
 2 types of proteins:
 a. “integral” membrane proteins-which are in contact
with both sides of the membrane; provides anion
channels through the RBC membrane
 b. “peripheral” proteins – located and limited to the
cytoplasmic/inner surface of the membrane forming
the RBC cytoskeleton; gives the cell its biconcave
structure
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Types of membrane PROTEINS
Integral Proteins
Glycophorin A
Glycophorin B
Glycophorin C
Anion- exchange channel
protein
(band 3)
Peripheral Proteins
Spectrin
Actin (band5)
Ankyrin (band 2.1)
Band 4.1 and 4.2
Band 6
Adducin
LIPIDS on the membrane
 phospholipids
= 50 %;
cholesterol
= 40 %;
glycolipids
= 10 %
 PHOSPHOLIPIDS form a bilayer
 hydrophobic (nonpolar) tails towards inside of cell
 hydrophilic (polar) head groups towards outside
(extracellular) or the inside (cytoplasmic ) surface
  the outer leaflet (external layer)

contains electrically
neutral glycolipids and choline phospholipids; while
the inner leaflet (internal cytoplasmic layer) predominantly
contains phosphatidyl serine which is negatively charged.
CARBOHYDRATES on the membrane
 Carbohydrates : forms the glycocalyx, serving as
a negatively charged barrier , around the
outside of the RBC membrane.
 important in preventing cells from adhering
(attachment) to one another, or adhering to the
endothelium (vein wall)
BLOOD GROUP ANTIGENS
on the RC membrane
Majority carried on transmembrane proteins
Few antigens carried on glycosylphosphatidyl -
inositol (GPI)- linked proteins or on glycolipids
Some transmembrane proteins interact with other
transmembrane proteins
Ex: (band 3 and GPA) like Kell and Kx, Rh and RhAG
 Some antigens are adsorbed from plasma : Lewis,
Chido
Red cell membrane antigens
Red cell membrane
antigens
PROPERTIES of RC membrane
 RBCs are biconcave disks, mean diameter of 7-8 µm
 Have more surface area than volume, which creates a
soft, pliable cell.
 Mature cells have no nucleus or mitochondria, but it is
packed with enough metabolism to exist for 120 days.
PROPERTIES of RC membrane
DEFORMABILITY
 red cell must be easily deformed/change shape
when these pass through small
 advantageous
openings or channels, as in the spleen
 Causes of loss of deformability / rigidity of cell :
 Loss of ATP  decreased phosphorylation of spectrin
 Increase deposition of calcium onto cells
 examples : spherocytes, “bite cells”

 cell become easily lyzed
PERMEABILITY
important to prevent colloidal hemolysis and

control the volume of RBC:
favorable to active cation transport
to water and anions, like chlorides
permeable
and bicarbonate
relatively impermeable to cations like Na and K
Intracellular : extracellular ratio of Na -1:12;
K -25:1
pump for active transport (requiring
cationic
ATP) of Na and K .
is transported outward from cell,
Ca
Ca- ATPase pump
depends on
( calcium-binding protein)- control
Calmodulin
the ATPase pump; prevent excessive intracellular
buildup which leads to rigidity.
ATP is depleted, Na and Ca accumulate
When
intracellularly, K and water get out of the cell
dehydration and rigidity of cell  easily
sequestered (trapped) in the spleen , thus
decrease in RBC survival.
end