antibodies immune system and immunotechnology

Types
Function
Structure

1. VIVEKANANDHA Submitted to Ms.S.Anandhi Assistant Professor PG & Research Department of Biotechnology Vivekanandha Arts and Science College For Women Sankari Submitted by DHANALAKSHMI.S II- Bsc Biotechnology Vivekanandha Arts and Science College For Women Veerachipalayam,Sankari Assignment on “ ANTIBODY ” IMMUNE SYSTEM AND IMMUNOTECHNOLOGY ARTS & SCIENCE COLLEGE FOR WOMEN [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 Dt., Tamil Nadu PG & RESEARCH DEPARTMENT OF BIOTECHNOLOGY

2. antibody

3. SYNOPSIS Introduction of Antibody Structure of Antibodies Types if Antibodies Properties of Antibodies Biological functions

4. INTRODUCTION OF ANTIBODY Antibodies, also known as immunoglobulins, are proteins produced by B cells (a type of white blood cell) in response to the presence of foreign substances, such as viruses, bacteria, or toxins, in the body. They play a crucial role in the immune system by:
1. Recognizing and binding to specific antigens (foreign substances)
2. Marking antigens for destruction by other immune cells
3. Neutralizing pathogens and toxins
4. Activating complement proteins to enhance immune response

5. Structure of antibody An antibody, also known as an immunoglobulin , is a Y-shaped protein produced by B cells in response to the presence of foreign substances, such as viruses, bacteria, or toxins. The antibody structure consists of: 1. *Heavy Chains (H)* : Two long chains that make up the stem of the Y, with a constant region (CH) and a variable region (VH). 2. *Light Chains (L)* : Two shorter chains that make up the arms of the Y, with a constant region (CL) and a variable region (VL). 3. *Variable Regions (VH and VL)* : Unique regions that recognize and bind to specific antigens. 4. *Constant Regions (CH and CL)*: Regions that interact with other immune cells and determine the antibody’s class and function.

6. Structure of Antibody 5.*Hinge Region: A flexible region connecting the two arms of the Y, allowing for flexibility and movement. 6. *Fab Region (Antigen-binding fragment)*: The arms of the Y that bind to antigens. 7. *Fc Region ( Crystallizable fragment)*: The stem of the Y that interacts with other immune cells.

7. TYPES OF ANTIBODIES IgM to a microbial attack by B cells.
It is the largest antibody and is found in a pentameric form. It circulates in the blood and lymph and constitutes 6% of the total antibody content in the serum.
It is involved in agglutination and opsonization .

8. Igg Structure :
- Monomeric (single Y-shaped unit)
- Composed of two heavy chains (γ) and two light chains (κ or λ) Functions: - Provides long-term immunity against infections
- Neutralizes pathogens and toxins
- Activates complement system (enhances immune response)
- Crosses the placenta gives the immunity to fetus .

9. IgG Subclasses - IgG1 (60% of total IgG)
- IgG2 (20% of total IgG)
- IgG3 (10% of total IgG)
- IgG4 (10% of total IgG) Characteristics :
- High affinity for antigens
- Long half-life (average 23 days)
- Can activate complement system
- Involved in antibody-dependent cellular cytotoxicity (ADCC)

10. IgA Structure :
- Dimeric (two Y-shaped units linked by a J-chain)
- Composed of two heavy chains (α) and two light chains (κ or λ)
- Secretory component (SC) is added in mucosal areas, forming secretory IgA ( sIgA ) Functions: - Provides protection against pathogens in mucosal surfaces (respiratory, gastrointestinal, genitourinary tracts)
- Neutralizes viruses, bacteria, and toxins
- Prevents attachment of pathogens to epithelial cells
- Involved in immune exclusion (removes pathogens from mucosal surfaces)

11. IgA Characteristics :
High affinity for antigens
- Short half-life (average 6 days)
- Can activate complement system
- Involved in antibody-dependent cellular cytotoxicity (ADCC) Subclasses: - IgA1 (found in serum and mucosal areas)
- IgA2 (found primarily in mucosal areas)
Secretory IgA ( sIgA ) is the primary antibody in mucosal surfaces, providing immune protection against pathogens. IgA deficiency is the most common primary immunodeficiency, increasing susceptibility to infections.

12. IgD as a monomer and weighs around 1,80,000 dalton .
It comprises less It is involved in the production of the antibody by B cells.
It is present than 1% of the total antibody content in serum.
It acts as a receptor on B cell surface and participates in B cell activation and differentiation.

13. IgE IgE is present in the least amounts, around 0.02% of the antibody content in the serum.
These are present in the linings of the respiratory and intestinal tracts and respond to allergic reactions.
This is found as a monomer in the body and weighs about 200,000 Dalton

14. Properties of Antibody 1. _Specificity_ : Antibodies recognize and bind to specific antigens. 2. _Affinity_: Antibodies have a high affinity for their target antigens. 3. _Avidity_: The overall binding strength of an antibody to an antigen. 4. _Valence_: The number of antigen-binding sites on an antibody. 5. _Cross-reactivity_: Antibodies may bind to similar antigens or epitopes. 6. _Neutralization_: Antibodies can neutralize pathogens and toxins.

15. Properties of Antibody 7. _Activation of complement_: Antibodies can trigger the complement system. 8. _Antibody-dependent cellular cytotoxicity (ADCC)_: Antibodies can trigger cell-mediated killing. 9. _Half-life_: Antibodies have varying half-lives, affecting their persistence. 10. _Isotype switching_: Antibodies can change classes (e.g., IgM to IgG) during an immune response. 11. _Somatic hypermutation _: Antibodies can undergo mutations, increasing affinity. 12. _Immunological memory_: Antibodies contribute to long-term immune memory.

16. Biological functions of Antibodies 1. _Neutralization_: Binding to pathogens, such as viruses and bacteria, to prevent infection. 2. _Marking for destruction_: Identifying pathogens for destruction by other immune cells. 3. _Activation of complement_: Triggering the complement system to enhance immune response. 4. _Antibody-dependent cellular cytotoxicity (ADCC)_: Recruiting immune cells to destroy pathogens. 5. _Immune regulation_: Regulating immune responses to prevent excessive inflammation.

17. Biological functions of Antibodies 6. Immunological memory_: Providing long-term immunity against pathogens. 7. _Passive immunity_: Transferring immunity from mother to child or through vaccination. 8. _Pathogen removal_: Facilitating removal of pathogens from the body. 9. _Inflammation reduction_: Reducing inflammation by binding to pro-inflammatory molecules. 10. _Tolerance maintenance_: Maintaining tolerance to self-antigens, preventing autoimmunity.

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