Differential Expression of T-Cell Adhesion Molecules and LFA-1-Dependent Intercellular Adhesion in HgCl2-Induced Autoimmunity and Immune Suppression

    loading  Checking for direct PDF access through Ovid

Abstract

Exposure of Brown Norway (BN) rats to HgCl2 induces Th2-mediated systemic autoimmunity. In contrast, in Lewis rats, HgCl2 induces immune suppression, mediated by CD8+ T cells. HgCl2 was previously found to enhance expression of LFA-1, ICAM-1 and CD134 (OX40) on T cells in BN rats. In the present study, T cells from Lewis rats were studied at day 4 after injection of HgCl2. CD8+ T lymphoblasts were significantly increased, which were predominantly CD45RChi, and which showed enhanced LFA-1 expression. Furthermore, CD4+ CD45RChiT cells showed increased number of ICAM-1+ cells, whereas expression of CD134 and CD26 was relatively decreased in CD4+ T lymphoblasts. Ex vivo experiments demonstrated that HgCl2-exposure of BN rats, but not of Lewis rats, significantly enhances PMA [phorbol 12-myristate 13-acetate]-induced lymphocyte aggregation, mediated by LFA-1 and ICAM-1. In conclusion, HgCl2-injected Lewis rats show early signs of T-lymphocyte activation, predominantly on CD8+ cells. Strain-dependent effects of HgCl2 on cell adhesion molecules and expression of CD134 may play an important role in the development of either autoimmunity or immune suppression.

Related Topics

    loading  Loading Related Articles