[The acquisition of antibody diversity studied in anuran amphibians (author's transl)]

For T and B lymphocytes, the capacity of recognizing diverse antigens is acquired early in ontogeny. This is shown for T cells by graft rejection and mixed leucocyte reaction experiments and for B cells by the heterogeneity of antibody response in young larvae which only possess a small number of lymphocytes. Thus any proposed mechanism for the generation of antibody diversity in frogs has to take into account: (a) that such diversity is acquired within about 21-30 days after fertilization in larvae whose lymphocyte generation time is 36-40 h; (b) that genetically identical animals have similar immune responses as revealed by mixed leucocyte reaction for T cell responses and by isoelectric focussing patterns for anti-dinitrophenyl and anti-sheep red blood cells antibodies for B cells.