Modulation of age-related development of contact sensitivity in mice by adult thymectomy

The effect of adult thymectomy on antibody production and on the development of contact sensitivity to picryl chloride in mice of different ages was studied. An age-dependent decline in the ability to develop contact sensitivity was found to be counteracted by thymectomy. In contrast, antibody production was regularly decreased by thymectomy in mice of all ages. A hypothesis is put forward in which the development of contact sensitivity may be regulated by long-lived thymus-dependent suppressor cells which do not affect antibody formation.