[Role of an insoluble thymus fraction in the differentiation of T lymphocytes].

An insoluble thymic fraction, free of both thymocytes and thymic hormone, was injected intraperitoneally to C57B1/6 mice. Following this injection, marked changes were noted in thymocyte populations: these consisted mainly in a significant increase of subcapsular prothymocytes, peaking at day 7. These observations were made by histological examination and confirmed by a study of physical characteristics of thymocyte populations. The possibility that this insoluble thymic fraction might have a biologically active component responsible for prothymocytes recruitment is examined.