[Effect of cortisone-resistant thymocytes on endogenous colony formation in inbred mice]

Endogenous colonies in the spleen of sublethally irradiated (CBA X C57BL/6) E1 hybrid mice were recorded after the injection of thymocytes and the lymph node cells from the hydrocortisone-treated and intact CBA mice. Cortisone-resistant thymocytes failed to suppress the endogenous colony formation, whereas the lymph node cells produced a distinct suppressive effect on the endogenous colonies. After the injection of cortisone-resistant thymocytes the number of colonies in the spleen of individual recipients was double that in control irradiated hybrids.