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03. Component of HUMORAL IMMUNITY –Anti bodies

Component of HUMORAL IMMUNITY –Anti bodies

 

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1. Each antibody molecule is made of 2 heavy chains and 2 light chains ,Held together by disulphide bonds

 

2. divided into CLASSES or ISOTYPES by type of heavy chains

 

3. each antibody has an

  • antigen binding­ portion(Paratope)
  • functional portion(can fix complement, attach to phagocytes and activate NK cells)

1. Antibodies recognize antigens that are three-dimensional in a 'lock and key' manner.

 

2. They can recognize soluble or cell surface antigens.

 

3. They can recognize antigens that are proteins, carbohydrates, lipids or nucleic acids.

 

4. The first antibody to he secreted is IgM

 

5. Then, under the influence of cytokines by T helper cells, the B cells switches to secreting IgG,IgA or IgE

 

6. This is called ISOTYPE SWITCHING.

 

 

IgE

IgG

IgA

IgM

Form

Monomer

Monomer

Dimmer

Pentamer

Hervey chain

£

γ

α

µ

Placental transfer

-

+ (passive immunity lasts for 3-6 months)

-

-

Present in secretion

-

Milk

Mucus(RS,GIT,GUT), gastric fluid ,tears ,saliva , Milk (colostrums)

Mucus

Surface of B lymphocytes

Main Function

Protection against parasites

Transfer immunity to fetus

Locally protect from infection

Agglutinating bacteria

Other features

Type 1 hypersensitivity

Found ↑ [ ] in Body fluid

Main antibody produce in 2ry response

Major antibody found in external secretion

1st antibody produce in immune response

 

 

ACTIONS OF ANTIBODIES:

 

Antibodies are secreted by plasma cells and circulate in the blood to the site of infection to eliminate the antigen.

 

Antibodies can do the flowing to help protect against infections.

 

1) Neutralization of toxins: so Own they cannot act on cells

 

2) Neutralization of viruses so that they cannot bind to cellular receptors and enter cells.

 

3) Agglutination/ immobilization/ of bacteria and viruses

 

4) Opsonisation of bacteria arid viruses

 

5) Activation of the classical complement pathway

 

6) Antibody dependent cellular cytotoxicity by NK cells

 

7) Mast cell degranulation to promote acute inflammation

03. Component of HUMORAL IMMUNITY –Anti bodies 03. Component of HUMORAL IMMUNITY –Anti bodies Reviewed by Radiology Madeeasy on April 13, 2010 Rating: 5
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