Antibodies Flashcards
substances, specifically glycoproteins, produced by B lymphocytes or plasma cells (matured or differentiated B lymphocytes) in response to antigenic stimulation
ANTIBODIES
other term for ANTIBODIES
Immunoglobulins
Previously known as _____ ________ since it was
found to be concentrated on gamma region of serum protein electrophoresis.
gamma globulins
is the same as the antibody classes. Antibody classes depends on their heavy chain present and the heavy chain of the antibodies is basically used to name the antibodies
Isotype
5 HEAVY CHAINS
✓ Gamma (IgG)
✓ Mu (IgM)
✓ Alpha (IgA)
✓ Delta (IgD)
✓ Epsilon (IgE)
Gamma
IgG
Mu
IgM
Alpha
IgA
Delta
IgD
Epsilon
IgE
determined by the difference in the antibody structure in the constant region, specifically the amino acid sequence
Allotype
determined according to the difference in the variable region of the antibody
Idiotype
Composed of 2 identical light chains and 2 identical heavy chains (different chains are not allowed)
Four (4) polypeptide chains
Example of Light chains
Kappa & Lambda
synthesized with regulation of gene located in
chromosome 2
Kappa
formation of this is regulated by the gene located in chromosome 22
Lambda
synthesis of Mu, alpha, delta, epsilon regulated by the chromosome 14
Heavy chains
Both light and heavy chains are held together
by
COVALENT DISULFIDE BONDS
Heavy chains are interconnected by
DISULFIDE LINKAGES
Ig has 2 terminal regions:
Carboxyterminal & Aminoterminal
with constant amino acid sequence (constant region) AKA. Fc region
Carboxyterminal
(Crystallizable Fragment/ Fragment crystalline)
Fc region
with varying antibody specificity (variable region) AKA. Fab
Aminoterminal
where epitope of antigen interacts
Fab - Fragment for Antigen Binding or Antigen Binding Fragment
specific location where epitope of antigen interacts with the antibody
Hypervariable portion of Fab region
Treatment of monomer antibody with enzyme papain (cleave covalent bonds) will produce 3 fragments:
One Fc fragment
Two Fab fragments (monovalent)
fragment crystalline; involve in Ig biologic function
One Fc fragment
Biologic functions of Fc fragment is involved in:
✓ Complement Fixation
✓ Placental Transfer of antibody
✓ Binding site for cell/s
capable of antigen binding even without the Fc but cannot agglutinate or precipitate; separated 2 Fab fragments
Two Fab fragments (monovalent)
Treatment with pepsin results in digestion of Fc fragment → destroyed → leaving 2 Fab fragments. The two Fab fragments have two antigens combining sites (Bivalent)
therefore, it is capable of antigen binding, precipitation and agglutination