Abstract
The role of bone marrow-derived cells in the rejection of skin allografts in rats was investigated. Lewis rats, rendered tolerant of BN antigens and bearing healthy grafts, were thymectomized, irradiated with 900 rad, and injected with varying doses of either normal isologous bone marrow, normal lymph node cells, and/or lymph node cells presensitized to BN antigens. In some experiments rats were also adoptively sensitized to tuberculin. Results showed that, although necessary for the elicitation of tuberculin skin reactions, bone marrow cells are not needed for the rejection of previously tolerated skin allografts. Rats receiving lymph node cells alone rejected their grafts in about 6–7 days.