THYROIDITIS IN T CELL-DEPLETED RAT - SUPPRESSION OF AUTOALLERGIC RESPONSE BY RECONSTITUTION WITH NORMAL LYMPHOID-CELLS

  • 1 January 1976
    • journal article
    • research article
    • Vol. 25 (1), 6-16
Abstract
Qualitative, quantitative and functional differences were found in lymphoid cells of female thymectomized and irradiated (Tx-X) PVG/c strain rats as compared to normal females of the same strain. Tx-X rats were lymphopenic and had reduced numbers of cells within spleen and cervical lymph nodes, depressed transformation responses of peripheral blood lymphocytes to PHA [phytohemagglutinin], and a lower percentage killing of their spleen cells by [rabbit] anti-T[thymus-derived]-cell serum and complement. There was an increased percentage of immunoglobulin-bearing cells in the lymph nodes. Reconstitution of Tx-X rats by the i.v. route using syngeneic lymph node cells, spleen cells or thymocytes abrogated the autoimmune responses to thyroid components generally observed in this state. Lymph node and spleen cells, but not thymocytes, also prevented thyroid changes when given i.p. Bone marrow cells appeared to give enhanced responses. Quantitative studies showed that the relative proportions of the suppressor or autoregulatory cells in various lymphoid tissues were lymph node > spleen > thymus. Complete abrogation of the autoimmune responses was possible only when cells were administered within a short time of the final dose of irradiation; moderate thyroid change was again seen if transfer was delayed for 14 days post-irradiation. At 28 days, reconstitution had no influence on the development of the autoimmune responses. Preliminary characterization studies using an anti-T-cell serum and fractionation of lymph node cells on a linear Ficoll gradient suggested that the autoregulatory cell is a large T cell.