The document discusses antigens, which are substances that trigger immune responses by stimulating the production of antibodies. It covers the definition, structure, properties, characteristics, and various types of antigens, emphasizing their importance in immunology and medical research. Understanding antigens is critical for developing vaccines, diagnostics, and therapies for diseases.

1. VIVEKANANDHA
Submitted to:
Ms.S.Anandhi
Assistant Professor
PG & Research Department of Biotechnology
Vivekanandha Arts and Science College For Women
Sankari.
Submitted by :
N.DEVIKA
II-BSC BIOTECHNOLOGY
PG AND RESEARCH DEPARTMENT OF BIOTECHNOLOGY
VIVEKANADHA ARTS AND SCIENCE COLLEGE FOR
WOMEN VEERACHIPALAYAM,SANKAGIRI.
Title : ANTIGEN:CHARACTERISTICS AND TYPES.
Subject: IMMUNE AND IMMUNOTECHNOLOGY
ARTS & SCIENCE COLLEGE FOR WOMEN
Dt., Tamil Nadu[An ISO 9001:2015 Certified Institution]
(Affiliated to Periyar University, Salem
Recognised Under Section 2(f) &12(B) of the UGC Act, 1956)
Veerachipalayam, Sankari West (Post) – 637 303, Sankari Tk, Salem
PG & RESEARCH DEPARTMENT OF BIOTECHNOLOGY

2. ANTIGEN:CHARACTERISTI
CS
AND TYPES

3. 1. Introduction
2. Definition
3. Structure of Antigen
4. Properties of Antigen
5. characteristics of Antigen
6. Types of Antigen
7. Conclusion
SYNOPSIS

4. Antigens are substances that trigger an immune response, causing
the body to produce antibodies to fight them. Antigens can be:
- Proteins (e.g., viruses, bacteria, toxins)
- Carbohydrates (e.g., bacterial cell walls)
- Nucleic acids (e.g., DNA, RNA)
- Lipids (e.g., bacterial cell membranes)
INTRODUCTION

5. Antigens have specific regions called epitopes, which are
recognized by the immune system. When an antigen enters
the body, it is processed by immune cells, and the epitopes are
presented to T-cells and B-cells, triggering an immune
response.
Antigens can be:-
1. Exogenous (from outside the body, e.g., viruses, bacteria)-
2. Endogenous (from within the body, e.g., cancer cells, self-
proteins)
Understanding antigens is crucial in immunology,

6. DEFINITION
Antigens are substances that can trigger an immune response,
causing the body to produce antibodies or immune cells that
recognize and bind to them. Antigens are typically proteins,
carbohydrates, nucleic acids, or lipids that have specific regions
(epitopes) recognized by the immune system.
Key points:
- Substances that trigger an immune response
- Recognized by immune cells (T-cells, B-cells)
- Stimulate antibody production or immune cell activation
- Can be proteins, carbohydrates, nucleic acids, or lipids

7. STRUCTURE OF ANTIGEN
-Antigens have a unique structure that allows them to be
recognized by the immune system.
The key features are:
1. Epitopes (Antigenic Determinants): Specific regions on the
antigen’s surface that are recognized by immune cells (T-cells,
B-cells).
2. Molecular Shape: Antigens have a unique 3D shape that
allows them to bind to immune cells.

8. 3. Chemical Composition: Antigens can be proteins, carbohydrates,
nucleic acids, or lipids, each with distinct chemical properties.
4. Size: Antigens can vary in size from small molecules to large
proteins.
5. Complexity: Antigens can have complex structures, such as
branched chains or repeating units.
The structure of an antigen determines:
- Which immune cells recognize it
- How it is processed and presented to immune cells
- The type of immune response it triggers.

10. PROPERTIES OF ANTIGEN
Antigens have several key properties that determine their
interaction with the immune system:
1. Immunogenicity: Ability to stimulate an immune response.
2. Antigenicity: Ability to bind to antibodies or immune cells.
3. Specificity: Unique structure recognized by specific immune
cells.
4. Diversity: Wide range of antigens with different structures and
properties.
5. Complexity: Can have complex structures, such as branched
chains or repeating units.

11. 7. Chemical Composition: Can be proteins, carbohydrates, nucleic
acids, or lipids.
8. Stability: Can be stable or unstable, affecting their persistence in
the body.
9. Solubility: Can be soluble or insoluble, affecting their interaction
with immune cells.
These properties determine:
- How antigens are recognized and processed by the immune
system
- The type and strength of the immune response
- The effectiveness of vaccines and diagnostic tests.

12. CHARACTERISTICS OF ANTIGEN
1. Specificity: Unique structure recognized by specific immune
cells.
2. Immunogenicity: Ability to stimulate an immune response.
3. Reactivity: Ability to bind to antibodies or immune cells.
4. Diversity: Wide range of antigens with different structures
and properties.
5. Complexity: Can have complex structures, such as branched
chains or repeating units.
6. Molecular Weight: Can vary in size from small molecules to
large proteins.

13. 7. Chemical Composition: Can be proteins, carbohydrates, nucleic
acids, or lipids.
8. Stability: Can be stable or unstable, affecting their persistence
in the body.
9. Solubility: Can be soluble or insoluble, affecting their
interaction with immune cells.
10. Epitope Density: Number of epitopes (antigenic determinants)
per molecule.
These characteristics determine how antigens interact with the
immune system and influence the immune response.

14. TYPES OF ANTIGEN
The main types of antigens;
1. Exogenous Antigens: Come from outside the body (e.g., viruses,
bacteria, toxins).
2. Endogenous Antigens: Originate from within the body (e.g.,
cancer cells, self-proteins).
3. Hapten Antigens: Small molecules that become antigenic when
attached to a carrier protein.
4. Conjugate Antigens: Consist of a hapten attached to a carrier
protein.
5. T-Independent Antigens: Stimulate B-cells without T-cell help

15. 6. T-Dependent Antigens: Require T-cell help to stimulate B-cells
(e.g., proteins).
7. Autoantigens: Self-proteins recognized as foreign by the
immune system (e.g., in autoimmune diseases).
8. Tumor Antigens: Proteins or other molecules expressed by
cancer cells.
9. Allergens: Substances that trigger allergic reactions (e.g.,
pollen, dust mites).
10. Superantigens: Powerful antigens that activate large numbers
of T-cells (e.g., bacterial toxins).
Each type of antigen elicits a unique immune response, and
understanding these differences is crucial for developing effective
vaccines, diagnostics, and treatments.

16. CONCLUSION
Antigens are substances that trigger an immune response,
playing a crucial role in protecting the body against
pathogens and diseases. Understanding antigens and their
properties, types, and characteristics is essential for:
1. Developing effective vaccines and diagnostics
2. Understanding autoimmune diseases and allergies
3. Designing targeted therapies for cancer and infectiou.
4. Improving transplantation outcomes.

17. In summary, antigens are:
- Substances recognized by the immune system
- Triggers of immune responses
- Essential for immune function and protection
- Diverse in structure, properties, and functions
- Critical for medical research, diagnostics, and treatments
By understanding antigens, we can harness the power of the
immune system to prevent and treat diseases, improving
human health and well-being.

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20. THANK YOU