SHIFT FROM ANTIINFLAMMATORY TO PROINFLAMMATORY CYTOKINE PROFILES IN MICROGLIA THROUGH LPS-GAMMA-MEDIATED OR IFN-GAMMA-MEDIATED PATHWAYS

In this study, cytokine mRNA profiles in microglia from newborn rats w ere detected by in situ hybridization. Under natural culture condition s, microglia expressed the immunosuppressive transforming growth facto r-beta 1 (TGF-beta 1) and interleukin (IL) 10 to a greater degree than the pro-inflammatory cytokines IL-1 beta, IL-6, IL-12, interferon-gam ma (IFN-gamma) and TNF-alpha. High TGF-beta 1 and IL-10 levels could r eflect one mechanism for immune privelege within the CNS under physiol ogical conditions. Stimulation of microglia with LPS or IFN-gamma resu lted in strong up-regulation of proinflammatory cytokines, while TGF-b eta 1 and IL-10 were down-regulated. These effects of LPS or IFN-gamma are anticipated to reflect immunopathogenic processes within the CNS.