1. Group 2
Wajjiha Amjad 1378-FBAS/BSBT/F20
Ayesha Ishtiaq 1383-FBAS/BSBT/F20
Sheeza Arif 1386-FBAS/BSBT/F20
Shabana Noor 1399-
FBAS/BSBT/F20
Submitted to: Dr. Sadaf
Submission date: October 18, 2022
2. • A protein made by plasma cells (a type of white blood
cell) in response to an antigen (a substance that causes
the body to make a specific immune response).
• Each antibody can bind to only one specific antigen. The
purpose of this binding is to help destroy the antigen.
• anti- "against" + body.
Antibody:
3. Structure of Antibody
• Each antibody consists of four polypeptides– two heavy
chains and two light chains joined to form a "Y" shaped
molecule.
• The amino acid sequence in the tips of the "Y" varies greatly
among different antibodies.
• This variable region, composed of 110 -130 amino acids, give
the antibody its specificity for binding antigen.
• The variable region includes the ends of the light and heavy
chains.
4. • Treating the antibody with a protease can cleave this region,
producing Fab or fragment antigen binding that include the
variable ends of an antibody.
• The constant region determines the mechanism used to
destroy antigen.
• The variable region is further subdivided into hypervariable
(HV) and framework (FR) regions.
• Hypervariable regions have a high ratio of different amino
acids in a given position, relative to the most common amino
acid in that position.
5.
6. • Within light and heavy chains, three hypervariable regions exist
– HV 1, 2 and 3.
• Four FR regions which have more stable amino acids sequences
separate the HV regions.
• The HV regions directly contact a portion of the antigen's
surface hence called complementarity determining regions, or
CDRs.
• The FR regions form a beta-sheet structure which serves as a
scaffold to hold the HV regions in position to contact antigen.
7. • There are millions of antigen/epitope.
• Our immune system has the ability to produce specific
antibody against specific antigens.
• This diversification in antibody is known as antibody
diversity.
• There are variety of pathogens entering in our body so we
should have huge collection of antibody.
• Two process that produce diversity and variety to the
antibody genes take place in germinal cell through B cell
maturation.
8. • Somatic cells contains a relatively small number of Ig genes.
• Somatic hyper-mutation means mutation is very active at
this variable region.
• At V region variation take place.
• Variable region of Ig chains is encoded by multiple gene
segments.
• These segments arrange to form a functional variable region
exons.
Somatic Hyper-mutation
9. • A process by which B cells randomly assemble Ig gene
segments to form functional variable region exon.
• Process occurs at the early development of
lymphocytes.
• Two types of recombination occurs one in V region and
one in C region.
• Recombination in C region gives the idea of what kind
of antibody will produce.
VDJ Recombination
10. • Recombination takes place in heavy and light chains.
• The V ( variable) region of L chain is coded by a one of the
V J recombinant.
• V region of H chain is coded by a one of the VDJ
recombinant.
• The C (Constant) region of both H & L chain is coded by
one of the C region of gene.
• In human there are 51Vh segments, 27Dh segments, 6Jh
segments and series of C region.
11. • V region is coded by 3 type of gene segments: V D & J
segments.
• V D J gene segments encode the variable domain of IG
heavy chain.
• During B cell maturation and somatic cell recombination
randomly selected D and J segments join and intervening
DNA is discarded.
• Next randomly selected V segment and DJ rearranged
segment joins and again intervening DNA is discarded.
VDJ recombination – heavy
chain gene family
12. • Heavy chain then reassembled to make Ig that is unique
to particular B cell and will fight against specific antigen.
• Recombination in C region gives the idea of what kind of
antibody will produce.
• The region present after V region antibody will name
after it.
M D G E A
V D J
Variable Region Constant Region
µ & γ E α
13. • No recombination , B cell keep producing Ig M.
• Ig M is most dominant form.
• First type of antibody produced when B cell is not
specific and don’t know specific antigens.
• Ig loci has multiple gene segments and these can be
rearranged in many possible ways combination.
• This leads to antibody diversity.
14.
15. • Classification of antibodies is by the means in which they
are created from lymphocytes.
• The antibodies can be classified into two primary types:
Monoclonal
Antibodies:
Polyclonal
Antibodies:
16. Monoclonal Antibodies:
• Monoclonal Antibodies are generated by identical B-cells
which are clones from a single parent cell.
• mAbs have the monovalent affinity and only recognize the
same epitope of an antigen.
Polyclonal Antibodies:
• Polyclonal Antibodies are the antibodies usually
produced by different B-cell clones in the body.
• pAbs can bind to many epitopes of a single antigen.
17.
18. Polyclonal Antibodies
(pAbs)
Monoclonal Antibodies
(mAbs)
Produced by different clones
of plasma B-cells.
A heterogeneous antibody
population
Produced by a single clone of
plasma B-cells.
A homogeneous antibody
population.
1.
2.
3.
Mixture of immunoglobulin
that are secreted against a
particular antigen.
A population of antibodies that
are produced by a single clone
of plasma B-cells.
19. Polyclonal Antibodies
(pAbs)
Monoclonal Antibodies
(mAbs)
Tolerant of small changes in
protien structure.
Interact with different
epitopes on the same antigen.
Intolerant to changes in
protein structure.
Interact with a particular
epitope on the antigen.
4.
5.
6.
Production doest not
required hybridoma cell
lines.
Production requires hybridoma
cell lines.
20. Conclusions
• Conclusively, For applications such as therapeutic drug
development that require large volumes of identical antibody
specific to a single epitope, monoclonal antibodies are a better
solution.
• For general research applications, however, the advantages of
polyclonal antibodies typically outweigh the few advantages
that monoclonal antibodies provide.
• With affinity purification of serum against small antigen
targets, the advantages of polyclonal antibodies are further
extended.
