Immunoglobulins, also known as antibodies, are Y-shaped proteins produced by B lymphocytes that bind to pathogens like bacteria and viruses. They have a variable region that changes to bind different antigens and a constant region. The five major classes of immunoglobulins are IgG, IgM, IgA, IgE, and IgD. Immunoglobulins recognize and bind to specific antigens, which can trigger immune responses like phagocytosis. While antibodies are a type of immunoglobulin, not all immunoglobulins function as antibodies.

1. Immunoglobulins
16 July 2021 Abhijit Debnath BP605T and Biotech Unit-1 1
CO1.1
Noida Institute of Engineering and Technology
(Pharmacy Institute) Greater Noida
Abhijit Debnath
Asst. Professor
NIET, Pharmacy
Institute
Unit: 3
Subject Name: Biotechnology
(BP605T)
Course Details
(B. Pharm 6th Sem)

2. Immunoglobulins
16 July 2021 Abhijit Debnath BP605T and Biotech Unit-1 2
 Introduction to Immunoglobulins
 Structure of Immunoglobulins
 Structure of Immunoglobins
 Types of Immunoglobins
 How Antibodies Work?
 Functions of Antibody
 Monoclonal Antibodies
 Similarities Between Antibody & Immunoglobulin
 Differences Between Antibody & Immunoglobulin
CO1.1
Noida Institute of Engineering and Technology
(Pharmacy Institute) Greater Noida

3. 16 July 2021 Abhijit Debnath BP605T and Biotech Unit-3 3
INTRODUCTION TO IMMUNOGLOBINS CO3.1
 The humoral immunity is mediated by a special group of antigen binding proteins called
Immunoglobulins or antibodies, produced by B-lymphocytes.
 This Y-shaped proteins detect and bind to harmful specific substances like antigens -
bacteria and other foreign substances.
 Since the majority of the antibody types are found in this globulin fraction, the
antibodies are also called as Immunoglobulins.
 In 1931, Tiselius and Kabat identified and isolated the antibodies from the blood plasma
by electrophoretic mobility assay.
 WHO officially coined the term Immunoglobulin (Ig) for antibodies in 1964.
 The production of antibodies are carried out by B lymphocyte.
 Immunoglobulins can either be membrane-bound (B-cell receptor) or secreted
(antibody).
All Antibodies are Immunoglobulins, but all Immunoglobulins are NOT Antibodies,
Currently, the term antibody and immunoglobulin are used synonymously.

4. 16 July 2021 Abhijit Debnath BP605T and Biotech Unit-3 4
 All the immunoglobulin (lg) molecules basically consist of
 Two identical heavy (H) chains (Molecular Weight 53,000 to
75,000 each) and
 Two identical light (L) chains (mol. wt. 23,000 each) held
together by disulfide linkages and non-covalent interactions.
 Each heavy chain contains approximately, 450 amino acids
 Each light chain has 212 amino acids.
 There are five types of Ig heavy chain (in mammal) denoted by the
Greek letters: α, δ, ε, γ, and μ.
 There are two types of Ig light chain (in mammal), which are called
lambda (λ) and kappa (κ).
 The heavy chains of lg are linked to carbohydrates, hence
immunoglobulins are glycoproteins
STRUCTURE OF IMMUNOGLOBINS CO3.1

5. 16 July 2021 Abhijit Debnath BP605T and Biotech Unit-3 5
 Both types of chains (heavy and light) are comprised of
two regions:
 Variable region and Constant region.
 The region that changes to various structures
depending on differences in antigens is called the
variable region.
 The region that has a constant structure is called
the constant region.
STRUCTURE OF IMMUNOGLOBINS CO3.1

6. 16 July 2021 Abhijit Debnath BP605T and Biotech Unit-3 6
TYPES OF IMMUNOGLOBINS CO3.1
 There are five classes of Immunoglobulin : IgM, IgG, IgM, IgA, IgE and IgD
IgA

7. 16 July 2021 Abhijit Debnath BP605T and Biotech Unit-3 7
TYPES OF IMMUNOGLOBINS CO3.1

8. 16 July 2021 Abhijit Debnath BP605T and Biotech Unit-3 8
TYPES OF IMMUNOGLOBINS CO3.1

9. 16 July 2021 Abhijit Debnath BP605T and Biotech Unit-3 9
HOW ANTIBODIES WORK? CO3.1

10. 16 July 2021 Abhijit Debnath BP605T and Biotech Unit-3 10
HOW ANTIBODIES WORK? CO3.1

11. 16 July 2021 Abhijit Debnath BP605T and Biotech Unit-3 11
HOW ANTIBODIES WORK? CO3.1

12. 16 July 2021 Abhijit Debnath BP605T and Biotech Unit-3 12
FUNCTIONS OF ANTIBODY CO3.1
 IgG provides long term protection because it persists for months and years after the prescence of the antigen that
has triggered their production.
 IgG protect against bacteris, viruses, neutralise bacterial toxins, trigger compliment protein systems and bind
antigens to enhance the effectiveness of phagocytosis.
 Main function of IgA is to bind antigens on microbes before they invade tissues. It aggregates the antigens and
keeps them in the secretions so when the secretion is expelled, so is the antigen.
 IgA are also first defense for mucosal surfaces such as the intestines, nose, and lungs.
 IgM is involved in the ABO blood group antigens on the surface of RBCs.
 IgM enhance ingestions of cells by phagocytosis.
 IgE bind to mast cells and basophils wich participate in the immune response.
 Some scientists think that IgE’s purpose is to stop parasites.
 IgD is present on the surface of B cells and plays a role in the induction of antibody production.

13. 16 July 2021 Abhijit Debnath BP605T and Biotech Unit-3 13
MONOCLONAL ANTIBODIES CO3.1
Monoclonal antibodies
(mAbs) are antibodies
developed in a
laboratory to help our
bodies fight infection.

14. 16 July 2021 Abhijit Debnath BP605T and Biotech Unit-3 15
SIMILARITIES BETWEEN ANTIBODY AND IMMUNOGLOBULIN CO3.1
 Immunoglobulin and antibody are disease-fighting proteins developed by most vertebrates in response to a particular
antigen.
 Both immunoglobulin and antibody are components of the immune system.
 Both immunoglobulin and antibody are glycoproteins.
 Both of them contain similar regions in their molecules.
 Immunoglobulins are attached to the B cell membrane while antibodies float in the circulation.
 Both immunoglobulin and antibody comprise heavy and light chains.
 Both immunoglobulin and antibody comprise variable and constant regions.
 Both immunoglobulin and antibody are produced in response to the presence of an antigen.
 Both immunoglobulin and antibody can be found in secretions as well as in the circulation.
 Both immunoglobulin and antibody are involved in protecting the body from pathogens.

15. 16 July 2021 Abhijit Debnath BP605T and Biotech Unit-3 16
DIFFERENCES BETWEEN ANTIBODY AND IMMUNOGLOBULIN CO3.1
Immunoglobulin Antibody
 Immunoglobulin refers to any class of structurally related
proteins in the serum and the cells of the immune system
which functions as antibodies
 Antibody refers to a globin protein, which is produced by
B cells in response to a particular antigen
 Occurs on the surface of B cells  Freely occurs in the circulation
 Has a transmembrane domain in order to be attached to
the plasma membrane of B cells
 Does not have transmembrane domains
 Five classes are IgG, IgM, IgA, IgD, and IgE  A particular antibody is specific to a particular pathogen
 Function depends on the type of heavy chain  Non-self antigens are recognized by specific antigens and
are neutralized by antibodies

16. 16 July 2021 Abhijit Debnath BP605T and Biotech Unit-3 17
DIFFERENCES BETWEEN ANTIBODY AND IMMUNOGLOBULIN CO3.1
Immunoglobulin Antibody
 Immunoglobulin has a transmembrane domain in order
to be attached to the plasma membrane
 Antibody does not have a transmembrane domain.
 Apart from the antibody globulins, the immunoglobulin
class also contains other globulins such as cryoglobulin,
macroglobulin and abnormal myeloma proteins.
 Majority of the antibody types are found in this globulin
fraction, the antibodies are called as Immunoglobulins.
 WHO officially coined the term Immunoglobulin (Ig) for
antibodies in 1964.
 In 1931, Tiselius and Kabat identified and isolated the
antibodies from the blood plasma by electrophoretic
mobility assay.
All Antibodies are Immunoglobulins, but all Immunoglobulins are NOT Antibodies,
Currently, the term antibody and immunoglobulin are used synonymously.