Pg 145
The four different blood groups
AB
ABO
• The proteins found on the surface of the RBC are also known as antigen.
Note: These antigens do not stimulate the lymphocytes to produce antibodies.
The four different blood groups
• Classification of blood types are based on the type of antigens found on the surface of red blood cells.
The four different blood groups
‘Natural antibodies’
• Natural antibodies found in our blood.
• Antigens react with antibodies.
Natural antibodies Antibodies Occurs naturally and always present in the body.
Produced only in the presence of foreign objects like bacteria/virus.
Agglutination of blood
• Clumping / agglutination of blood occurs when:– Antigen A reacts with antibody a– Antigen B reacts with antibody b
Agglutination of blood
• Blood clumps block up small blood vessels and obstruct the flow of blood.
What happens when different blood groups are mixed in blood
transfusion?
• Blood donors• Blood receivers• Agglutination of donor’s RBCs
Why is blood group AB called the universal acceptor?
• Absent of antibodies in the plasma. • No reaction with antigens on other RBCs.
• “AB – sounds like acceptor”
Why is blood group O called the universal donor?
• No surface antigen on blood group O. • Will not react with natural antibodies in other
blood group.
• Antibodies a and b in the donor’s plasma would be diluted by the recipient's blood.
• Hence no effects of the antibodies on the recipient's RBC.
In summary
Blood group Receive blood from
A A,O B B,O
AB A,B,AB,O O O
Testing for blood group
Unknown X
Antibody A Antibody B
Check for AgglutinationAntigen A – antibody aAntigen B – antibody b
Test Yourself [pg145]
a)X – Blood group BY – Blood group ABZ – Blood group O
b) Serum from A contains antibody B. reacts with antigen B found on RBC to cause clumping.
C) Blood group O
d) A, AB
e) No surface antigen to cause agglutination of RBC. Antibodies a and b in the donor’s plasma would be diluted by the recipient's blood.Hence antibodies has no effects on the recipient's RBC.
Test Yourself [pg145]