ABSTRACT
Since the earliest days of the discovery of “athymia”, or, more exactly, thymic dysgenesis in the nude mouse, it has been known that the animal is not entirely devoid of the T-lineage cells. There are many more nu/nu spleen and lymph node cells, which are positive for the brain-derived antigen. The thymus epithelial stroma seems to need few fully competent T-cell progenitors to be primed for its normal development and it has been suggested for human thymic dysgenesis that it may be caused by the failure of T-cell progenitors to populate the epithelial anlage: the same may be true for the earliest development of the nude thymus. In addition, there may be an abnormal specificity repertoire and an abnormal distribution of T-cell clones in nude mice. There is the logical possibility that few maturing T cells may fill the peripheral compartments by clonal expansion even without antigenic stimulation.
