Restoration of Immunocompetency in Tolerant Lymphoid Cell Populations by Cellular Supplementation

Reconstitution experiments demonstrate that in mice the induction of unresponsiveness to human γ globulin (HGG) occurs more rapidly in specific bone marrow-derived (B) cells of the spleen (<3 days) than the previously reported induction period required for unresponsiveness in specific B cells of the bone marrow (8 to 15 days). This temporal variance could not be attributed to a difference in the gross localization of tolerogen in the respective lymphoid tissues. In contrast, the maintenance of the unresponsive state was similar in both B cell populations (40 to 50 days). Accordingly, the restoration of immunocompetency in unresponsive spleens could be accomplished in an adoptive transfer system by the addition of syngeneic thymocytes only at times predictable by the temporal pattern of the spontaneous loss of unresponsiveness described for bone marrow cells. The mere adoptive transfer of syngeneic thymocytes into tolerant animals did not similarly affect the unresponsive state.