Download Antibodies - INAYA Medical College

CLS 441
Characteristics of blood group antibodies:
• Classification of Blood Group Antibodies
– Antigen
- Immunologlobulin
- Antibody
- Hemoglobin
- Anti Human globulin
- Indirect Antiglobulin
Test
- Direct Antiglobulin
Test
- Autoimmune
Hemolytic Anemia.
- Hemolytic Disease of
New born
- Adenosine Triphosphate
- Citrate phosphate
dextrose
- Ethyldiamine Tetra
Acetic acid
- Acid Citrate dextrose
- Molecular weight
- Rhesus
• Immunohematology is one of the specialized branches of
medical science.
• It deals with the concepts and clinical techniques related to
Modern Transfusion Therapy.
• Merges aspects of hematology, immunology & genetics.
• Serologic, genetic, biochemical and molecular study of
antigens associated with membrane structures on the
cellular constituents of the blood
Antigens
Antigens: biological substance when introduce to
foreign circulation , it stimulate the immune response to
produce specific Antibody.
antigen may also be formed inside the body such as ABO
antigen
belong to protein called Immunoglobulin produced by plasma
cells react with Ag corresponding “ specifically”
•
IgG : with heavy chains gamma (γ).
•
IgA: with heavy chains alpha (α)
•
IgM: with heavy chains mu (μ)
•
IgD: with heavy chains delta(δ )
•
IgE: with heavy chains epsilon(Є)
IgG, IgM and IgA.
It is a Y-shaped molecule made of 2 heavy chains & 2 light chains.
Antibody
Antigen
Characteristics of blood group antibodies:
IgG:
• Is the predominant immunoglobulin in normal serum.
• Accounting for about 85% of the total immunoglobulin
• Is the only immunoglobulin to be transferred from mother to
fetus.
• Is the smallest antibody which has a MW of 150,000 Dalton
• Is capable of binding complement.
• Is predominantly produced during the secondary immune
response.
IgM:
• Accounts for about 10% of the immunoglobulin pool.
• Is the predominant antibody produced in a primary immune
response.
• and has the largest MW of 900,000.
• Because of its large size IgM cannot pass the placental
barrier to the fetus.
• Is complement binding.
IgA:
• Ig A with a MW of 160,000 constitutes 10 to 15 % of the
total circulatory immunoglobulin pool.
• Is the predominant immunoglobulin in secretions such
as, tears, saliva, colostrum, breast milk, and intestinal
secretions.
Type of Antibodies
• Based on their development, blood group antibodies are
classified into Natural and Immune antibodies.
1-Natural antibodies:
• Are red cell antibodies in the serum of an individual that are
not stimulated by previous red cell sensitization.
 Characteristics.
• Exhibit optimum in vitro agglutination. sometimes referred to as
complete antibodies.
• Give optimum reaction at a temperature of room or lower, and
they are also called cold agglutinins.
• These antibodies are of high MW that they can’t cross the
placental barrier, eg. IgM.
2- Immune antibodies:
Are antibodies stimulated by either transfusion or pregnancy,
i.e. as a result of immunization by red cells.
•
Characteristics
– Do not exhibit visible agglutination of saline- suspended
erythrocytes, and called incomplete antibodies
– React optimally at a temperature of 37C, and are so called
warm agglutinins.
– These antibodies can cross the placental barrier, e.g. IgG
1. Alloantibodies:•
Reacts with foreign Ag not present on patient’s own
RBC
•
Most produced as result of immune stimulation via
transfusion or pregnancy (usually during delivery)
2. Autoantibodies:•
Reacts with an Ag on patient’s own cells & with that
same Ag on the cells of other individuals
Antigen and Antibody Reactions
Type of reaction
1-Sensitization: simple combination
between red cell antigen and
corresponding antibody in a vivo or vitro
without visible agglutination.
2-Hemoagglutiation: reaction
between
red cell bound antigen and
corresponding antibody with visual
agglutination.
3-Hemolysis:
Reaction between red cell bound antigen
and antibody with complement fixation
resulting in releases of hemoglobin.
4-Neutralization (inhibition):
Reaction between red cell antigen and
corresponding antibody both in soluble state with
precipitation.
 Is the reaction of soluble Ag with soluble Ab.
 The reaction results in the formation of Ag-Ab complexes
(lattices)
Antigen
Antibody
• Complete or incomplete, cold or warm, natural or immune types
of antibodies.
• Amount of antibody.
• Amount of antigen.
• Avidity of antibody.
• PH of the reaction.
• Temperature of the reaction.
• Incubation time.
• Saline concentration.
• Type of additive (protein, enzyme).
• Speed and time of centrifugation.