antibody structure (immunology)

1. Immunology
Antibody

2. Introduction
• Antibodies /immunoglobulins are Antigen
binding glycoprotein produced only by B-cells,
In different forms.
• They are ‘’Y’’ shaped molecule with two
identical light chain (L)(220aa) & two
identical heavy chain (H)(440aa).
• The light & heavy chain are bound to each
other by disulfide bonds.

3. • The light chains usually are kappa & lamda.
• The heavy chain are ά,Ɛ,ṵ,γ,δ.These 5 heavy
chains are called isotypes.
• They determine the class of Antibody –
ISOTYPE Heavy chain
IgM ṵ
IgD δ
IgG γ
IgA ά
IgE έ

4. • Each L & H chain have a VARIABLE sequence
@ their N terminal region & a CONSTANT
sequence @ their C terminal region.
• C l ,vl,Ch,Vh are the regions of ANTIBODY.
• The variable regions i.e Vl Vh bind to the
Antigen .
• The Ag binding domain of Variable regions are
called CDR(complementarity Determining
Region) & the remaining parts are called
Frame work regions.

6. STRUCTURE OF ANTIBODY
• The secondary structure involves Anti parallel
ß sheets,Tertiary structure involves globular
domains.
• A region called HINGE region (cys ,pro) is a
flexible region present b/w two Fab
fragments.
• The chains are connected by disulfide linkages