This result showed that antibody genes are formed by DNA rearrangement. These are passed from generation to generation by the germ cells. Variation -number of gene fragments and the joining process. If an antigen appears that binds to one of the ramdomly generated membrane antibodies of a B-cell, then that clone can be selected to proliferate and differentiate into memory and antibody producing plasma cells. Somatic mutation- antibody improves with time During clonal selection, secondary immune responses produce much better antibody.
Mechanism involves specific mutations in the variable antibody gene coding for antibody.
New memory cells have random mutations. Selection by antibody binding insures that the highest affinity antibody produced will be selected. Class switch - DNA rearrangement changing the heavy chain constant gene in memory cells. Hybridomas -Fuse antibody producing cells with myelomas. Clones are immortal and produce monoclonal antibody.