Neonatal thymectomy in gnotobiotic CDF rats.

Neonatally thymectomized gnotobiotic rats did not develop the wasting syndrome which was a characteristic of the neonatally thymectomized conventional counterpart. Gnotobiotic and conventional thymectomized rats had haemolysin titres which were less in magnitude than the respective sham operated controls. The primary haemolysin response of gnotobiotic rats was significantly less than that of conventional rats during the 1st week of the response. Administration of thymus extract to adult gnotobiotic rats resulted in an increase in peripheral lymphocytes and enhancement of the primary haemolysin response to levels which were similar to those of the conventional rodent.