Characterization of the nude rat (rnunz). Functional characteristics

Gross histopathological and morphological observations in an accompanying paper confirmed the absence of a thymus and thymus-derived lymphocytes in the New Zealand athymic nude mutant (rnunz). In the present studies an analysis of the cell-mediated immune status of the rnunz rat is reported. Lymphocyte transformation studies showed that lymphocytes from the rnunz strain did not respond to mitogenic stimulation with the T lymphocyte specific mitogen Concanavalin A. This confirmed the absence of potentially functional T lymphocytes suggested by the morphological analysis. Lymphocytes from the rnunz strain also failed to initiate a graft versus host response, and the absence of host versus graft response established the immune deficit in cell-mediated immunity in the intact animals. Additionally, the rnunz strain has been used as a reference point to determine the effectiveness of neonatal thymectomy and adult thymectomy with irradiation as a means of depleting the host of T cells.