Clonal selection theory

The  clonal  selection  theory  elaborate  the  operation  of  the  humoral  immune system which is as follows.

- Even before an animal meets a foreign antigen, every immature antibody- producing cell makes one and only one speci?c type of antibody anchors and molecule this in the plasma membrane so in which it is exposed on the cell surface. A huge number of like antibody-producing cells exist in the animal that collectively expresses a very broad range of antibody speci?cities.

- If  a  foreign   antigen   is  encountered this   will   bind   to  those   antibody- producing   cells  that  are  displaying   antibody   which  has  an  appropriate binding  site for that particular antigen.  Every cell to that the antigen binds is stimulated to separate to form a population of identical cells are known as a clone. Still all the cells of the clone are genetically identical, they all produce antibody of the similar speci?city. The antibody now synthesized is no longer inserted into the plasma membrane but instead is secreted. Therefore, when an antigen is encountered,  it  ‘selects’  certain  antibody-producing cells  for  cell  division or  clonal selection and antibody production  simply on the basis of that cell surface antibodies bind that particular antigen. The speci?city of the antibody produced is therefore exquisitely tailored to the particular antigens encountered.