AIM:
Determination
of the blood group of the subject by ABO system and rhesus system.( Identify the unknown "blood types" of the synthetic
samples).
PRINCIPLE:
Binding of antigens to antibodies is
mediated by non-covalent bonds. The kinds of bonds that hold the antigen and
antibody together in this complex are the same ones that are generally involved
in producing the tertiary and quaternary structures of proteins, namely, ionic
bonds, hydrogen bonds, hydrophobic interactions, and van der Waals forces.
Interactions between antigen and
antibody involve non-covalent binding of an antigenic determinant (epitope) to
the variable region (complementarity determining region, CDR) of both the heavy
and light immunoglobulin chains. These interactions are analogous to those
observed in enzyme-substrate interactions and they can be defined similarly. To
describe the strength of the antigen-antibody interaction, one can define the
affinity constant (K) as shown:
Affinity K= [Ab–Lg]
‾‾‾‾‾‾‾‾‾ [Ab][Lg] |
= 104 to 1012
L/mol
|
||
Greater the K, the stronger the
affinity between antigen and antibody. These interactions are the result of
complementarity in shapes, hydrophobic interactions, hydrogen bonds and Van der
Waals forces.
Antibodies are also used to help
our bodies find and destroy "foreign" cells such as tumors. Because
antibodies bind tightly to only one type of structure on the surface of cells
(antigen), they can also be useful for identifying different types of blood
cells.
Our blood type is determined based
on the presence or absence of two proteins on the surface of our red blood
cells (Type A and Type B). There are four possible combinations of blood types
namely: Type A, Type B, Type AB, and Type O (contains neither A nor B
proteins). This is referred to as the ABO blood type. In addition, red blood
cells have a Rhesus factor or Rh, which is either present or absent. If the Rh
factor is present, the cells are referred to as Rh positive.
Blood group depends upon types of
antigen present or absent in the blood.There are four types of blood groups
.Type of blood group depends on presents or absent of rhesus factor in blood
cells When antibodies are mixed with their corresponding antigens on the
surface of large, easily sedimented particles such as animal cells, erythrocytes,
or bacteria, the antibodies cross-link the particles, forming visible
clumps. This reaction is termed agglutination.
Blood types are determined by using antibody
reagents that specifically react with the A, B, and Rh proteins on the surface
of red blood cells.
MATERIALS REQUIRED:
Slide, lancet, toothpick, cotton.
Reagents : Anti-serum A, Anti-serum B, and
Anti-serum D, alcohol.
PROTOCOL :
1. Take a
slide and label A, B and D.2. Spray the left “ring “ finger with ethanol or wipe it with an alcohol wiper and let it air dry.
3. Take a sterile lancet and puncture the fingertip.
4. Press the finger from top to bottom and put the blood drops on the slide.
5. Add a drop of anti-serum A, B and D to the blood drops.
6. Mix the antisera in with the blood using a separate toothpick. Place toothpicks in the biohazard waste.
7. After several minutes, observe agglutination and determine the blood type.
OBSERVATION
BLOOD TYPE
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ANTI-SERUM
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AGGLUTINATION
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A
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Anti-A
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NO AGGLUTINATION
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B
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ANTI-B
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NO AGGLUTINATION
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D
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ANTI-D
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AGGLUTINATIONfor more information
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