Network theory and it`s experimental evidence|clona?l selection theory?

     

          Network theory and it`s experimental evidence

-        Any discussion regarding of immune response not come to the end without mentioning Jern`s idiotype network theory.

-        In 1973, Neil Jerne proposed this theory so to give possible solution for regulation of immune system in 1985 he was honored with Nobel prize for this work.

-        This theory suggest that antigen enter the inside the body and activate very specific done of B cell secreting antibody against it.

-        The antigen binding site of an antibody composed of overlap between light and heavy chain domain called as idiotype.

      

 -        This recognizing are said to be complementary to antigen.

-        Antibody molecule itself being a protein so can behave as an antigen.

-        Antibody molecule against idiotype which exhibit internal image of an external antigen.

-        Likewise, anti-ant idiotype antibody as external images of primary antibody.

-        Theoretically this sequence can go further consisting network od idiotype antibodies, however experientially it has been observed that is extend to just their steps.

-        As a consequence of such antibody network antigen is readily remove from circulation.

-          At the same time each antibody feedback regulates formation of antibody once step ahead. Thus, controlling the overproduction of antibody

Experimental evidence: -

            Hemolytic plaque assay (jern`s hemolytic assay)

1.    This assay is used to quality number of antibodies producing plasma cell.

2.    Assay was introduced by jern`s and modified by qunning in 1968.

Protocol: -

Ø First mouse is immobilized with sheep RBCs

Ø After a fixed incubation period the spleen from mouse isolated.

Ø Then the solenocytes from the spleen are separated which contain plasma cell and this plasma cell produce antibody against sheep`s RBC`s.

Ø A microchamber of slides is prepared using two slides.

Ø The solenocytes are introduced in the microchamber along with sheep RBC`s and complement protein.

Ø The microchamber is incubated at 37⁰c for 2-3 hours.

Ø During this incubation period, plasma cell secretes the antibody against RBS`s (of IgM type).

Ø The secreted antibodies then bind to sheep RBC`s present in surrounding.

Ø Once antibody binds to sheep RBC`s present in surrounding.

Ø Once antibody binds to sheep RBC`s complement lysis the RBC`s.

Ø Due to this lysis of RBC`s a clear zone is produced around the antibody producing cell.

Ø Number of plaques are directly proportion to number of antibodies producing plasma cell.

         

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