MURINE SYSTEMIC AUTOIMMUNE-DISEASE INDUCED BY MERCURIC-CHLORIDE - T-HELPER CELLS REACTING TO SELF PROTEINS

HgCl2 induces a CD4+ T-cell-dependent systemic autoimmune disease in s usceptible strains of rats and mice. In rats, autoreactive T cells wer e shown to be involved, whereas in mice, attention has focussed on the demonstration of 'Hg-specific' T cells. To clarify these seemingly di fferent T cell involvements, T cells from B10.S mice treated with HgCl 2 for 1 or 8 weeks were analyzed for their capacity to mount anamnesti c responses against various self antigens (Ags) which either contained Hg or did not. T cells from donors short-term treated with HgCl2 fail ed to mount memory responses to Hg-free Ags, but mounted a significant response to HgCl2 and also reacted with Hg-containing self Ags. Inter estingly, T cells from donors long-term treated with HgCl2 showed a di fferent pattern of reactivity. They hardly reacted to HgCl2 and reacte d poorly to Hg-containing splenic proteins, but responded vigorously t o nuclei and fibrillarin irrespective of whether these self constituen ts had been treated with HgCl2 or not. Conceivably, the initial activa tion of T cells that recognize Hg in combination with nuclear self pro teins, such as fibrillarin, eventually results in activation of T cell s specific for the unaltered self proteins.