Abstract
Myasthenia gravis (MG) is an antigen-specific autoimmune disease caused by antibodies against acetylcholine receptors (AChR) at the post-synaptic membrane of the neuromuscular junction. Clinical and immunological data imply the involvement of AChR-specific T lymphocytes as helper cells for autoantibody production. Direct data to support this hypothesis, however, remain sparse. In the present study, a large population of MG patients was studied for evidence of peripheral blood T cell activation by several assays. Assays based on non-specific measurements of T cell activation as well as assays of antigenspecific clonal expansion were utilized. Levels of soluble IL-2 receptor in serum were modestly elevated in some patients, suggesting T cell activation. However, peripheral blood cells did not show evidence of IL- 2 receptor expression or enhanced reactivity to IL-2 in culture. Clonable T cells selected for hypoxanthine phosphoribosyl transferase (hprt) mutation, another non-antigen-specific marker for T cell activation, were not seen with increased frequency except in patients treated with purine analogs. Antigen- specific T cell activation was measured by proliferation assays using heterologous and autologous sources of AChR. Antigen-restimulated peripheral blood cell cultures were cloned by limiting dilution. The vast majority of patients failed to show convincing evidence of AChR specific T cell activation or clonal expansion; only 2 of 44 patients demonstrated clonable autologous AChR-specific T cells. An alternative hypothesis of T cell involvement in MG is proposed in which T cell activation is discontinuous and predominately directed at antigens other than AChR.
Original language | English (US) |
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Pages (from-to) | 492-499 |
Number of pages | 8 |
Journal | Journal of Neuroscience Research |
Volume | 45 |
Issue number | 4 |
DOIs | |
State | Published - 1996 |
Keywords
- T cell activation
- acetylcholine receptor
- hprt mutant selection
- soluble IL-2 receptor
ASJC Scopus subject areas
- Cellular and Molecular Neuroscience