Changes in the amphibian antibody repertoire are correlated with metamorphosis and not with age or size.

Tadpole and adult Xenopus, manipulated to be of comparable size, exhibited stage-specific antibody expression. The production of adult-type higher-affinity anti-DNP antibodies proved to be independent of the age and size of the individual and is concomitant with the completion of metamorphosis. The appearance of new antibody specificities at such a time suggests that their expression occurs with the cell turnover and renewal during a period of morphological changes.