L6 Antibody ppt immuno biology structure function types

Immuno biology

1. Antibodies and its type and functions

2. Contents Introduction of Antibody How antibody are produced Structure of antibody Basic functions of Antibody Different types of Antibody Their Functions and Structure

3. Antibody An antibody or immunoglobulin (Ig) is a glycoprotein that is made by plasma cells in response to an antigen and can recognize and bind to the antigen that caused its production. Binds to the antigen just as a key fits in to a specific lock.

4. Cont.… They are found in the blood or other body fluids of vertebrates. Antibody are used by the immune system to identify and neutralize pathogens such as bacteria , viruses or other agents. Generally all antibody are monomer i.e. two binding sites called bivalent. They are Y shaped.

5. How Ig Produced Antibodies are produced by the white blood cells called B lymphocytes or B cells. When an antigen binds to the B cell surface it stimulate the B cell & B cell convert it self in to plasma cell and they produce different types of antibodies.

6. Antibody is composed four polypeptide chain in which two identical light chains and two identical heavy chains. Chains are bonded via disulfide (s-s) linkage. The upper region is called variable region or (fab region) that bind with antigenic determinates sites Structure Of Antibody

7. Cont.… Variable region vary in all antibodies. The amino acid sequence of this region vary from cell to cell and time to time because in our body many different types of pathogen are entering and causing infection so body must prepared against all of them so, for this we must have at least one match with the help of that variable region.

8. Bottom region is called the crytallizable fragment (Fc) a portion of biological function e.g. Fc region IgG bind with the surface of macrophages b/c macrophages have receptor for the fc region of IgG. Constant region is same in all antibody.

9. Constant region is separated by variable region through hinge region. Heavy chains are of five types they are alpha, gamma, delta epsilon and mu. Alpha and gamma chain contains approximately 450 amino acids where as mu and epsilon chains have approximately 550 amino acids. Light chain are of two types Kappa and lambda .The approximate length of a light chain is 211-217 amino acids.

10. Function of immunoglobulins: Opsonization: Is a immune process where particles such as bacteria are targeted for destruction by an immune cell known as a phagocyte.

11. Neutralization Virus with the help of its surface molecules bind to its host cell membrane and cause infection. If their surface molecules is blocked by antibody then such types of viruses attach itself to host membrane but not able to cause infection in the host

12. Some pathogen release toxin which destroy our body cell if Ab attach to such toxin then its neutralize the harmful effect of toxin

13. Agglutination or clumping The clumping together by antibodies of microscopic foreign particles such as red blood cell or bacteria so that they form visible pellet like precipitate.

14. Different classes of antibodies There are five classes of antibodies are present IgM, IgG, IgA, IgE and IgD The antibody classes are named as correspond to their heavy chain types. IgG (gamma) They make up approximately 80% of the serum antibody's. They has a half-life 7 to 23 days.

15. IgG is a monomer Only class of antibody that can cross placenta and enter fetal circulation provide immunity to developing fetus. Function of IgG: Immunity to the new born. Neutralization of toxins.

16. IgM (Mu) They make up 13% of serum antibodies. They has a half –life of about 5 days. Mostly IgM are pentameric so have 10 binding sites. Frist immunoglobulin class produced a primary response to Ag.

17. Cause agglutination reaction during blood mismatch. Function Of IgM Activation of classical pathway Defense against multivalent antigen Act as opsonin .

18. IgA (alpha) They makes up approximately 6% of the serum antibody. They have half life of 5days IgA is dimer They found in mainly in body secretions such as saliva, mucous, tears and colostrum and provide immunity to new born.

19. Function of IgA Act as a secretory antibody Effective against viruses that causing influenza. Ig D (delta): They make up approximately o.2% of the serum antibodies. Ig D is a monomer.

20. This class of antibody are found in the surface of B lymphocytes. Function of Ig D: B cell activation to secret Ab. Act as receptor for antigen binding.

21. IgE (epsilon) Least abundant , low concentration in blood. Is a type of antibody that is found in mammals. Function Of Ig E: Provide immunity to parasites such as fasciola Bind to fc receptor on basophils and mast cells.