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The cross-talk between T cells and astrocytes occurring under physiological and, even more, neuroinflammatory conditions may profoundly impact the generation of adaptive immune responses in the nervous tissue. In this study, we used a standardized in vitro co-culture assay to investigate the immunomodulatory properties of astrocytes differing for age, sex, and species. Mouse neonatal astrocytes enhanced T cell vitality but suppressed T lymphocyte proliferation in response to mitogenic stimuli or myelin antigens, regardless of the Th1, Th2 or Th17 T cell phenotype. Studies comparing glia cells from adult and neonatal animals showed that adult astrocytes were more efficient in inhibiting T lymphocyte activation than neonatal astrocytes, regardless of their sex. Differently from primary cultures, mouse and human astrocytes derived from reprogrammed fibroblasts did not interfere with T cell proliferation. Overall, we describe a standardized astrocyte-T cell interaction in vitro assay and demonstrate that primary astrocytes and iAstrocytes may differ in modulating T cell function. [ABSTRACT FROM AUTHOR]

Abstract: Rapamycin is an oral immunosuppressant drug previously reported to efficiently induce naturally occurring CD4+CD25+FoxP3+ regulatory T (nTreg) cells re-establishing long-term immune self-tolerance in autoimmune diseases. We investigated the effect of rapamycin administration to SJL/j mice affected by PLP139–151-induced relapsing–remitting experimental autoimmune encephalomyelitis (RR-EAE). We found that oral or intraperitoneal treatment at the peak of disease or at the end of the first clinical attack, dramatically ameliorated the clinical course of RR-EAE. Treatment suspension resulted in early reappearance of disease. Clinical response was associated with reduced central nervous system demyelination and axonal loss. Rapamycin induced suppression of IFN-γ, and IL-17 release from antigen-specific T cells in peripheral lymphoid organs. While CD4+FoxP3+ cells were unaffected, we observed disappearance of CD4+CD45RBhigh effector T (Teff) cells and selective expansion of Treg cells bearing the CD4+CD45RBlowFoxP3+CD25+CD103+ extended phenotype. Finally, the dual action of rapamycin on both Teff and Treg cells resulted in modulation of their ratio that closely paralleled disease course. Our data show that rapamycin inhibits RR-EAE, provide evidence for the immunological mechanisms, and indicate this compound as a potential candidate for the treatment of multiple sclerosis. [Copyright &y& Elsevier]