Region-specific expression of immunoregulatory proteins on microglia in the healthy CNS

In accordance with a high degree of spatial organization in the central nervous system (CNS), most CNS diseases display a regional distribution. Although microglia have been established as key players in various CNS diseases, it is not yet clear whether microglia display region-specific properties. Therefore, this study aimed to evaluate the existence of distinct microglia phenotypes in various regions of the healthy, adult mouse CNS. Using ex vivo flow cytometric analysis surface expression of CD11b, CD40, CD45, CD80, CD86, F4/80, TREM-2b, MHCII, CXCR3, CCR9, and CCR7 were analyzed. Most of these immunoregulatory markers were found on microglia and showed significant region-specific differences in expression levels. These findings considerably corroborate the existence of immunological diversity among microglia in the healthy, unchallenged CNS of adult mice. (C) 2008 Wiley-Liss, Inc.