| Summary: | 碩士 === 台北醫學院 === 醫學研究所 === 88 === 英文摘要
The present study was aimed to examine the changes of different immune molecules on microglial cells in 7-day-old rats receiving an intraperitoneal injection of Gram-positive bacteria product, lipoteichoid acid (LTA). Microglia constituted several immune molecules, such as the major histocompatibility complex class II antigens, complement type 3 receptors and macrophage lysosomal antigens of unknown function, and can be labelled with OX-6, OX-42 and ED-1 antibodies, respectively. Of the above-mentioned immune molecules, microglia labelled with OX-42 or ED-1 were increased in their populations and staining intensity in LTA-treated rats than those in saline-treated ones. It is also true for OX-42 or ED-1 labelled macrophages in the meninges and the choroids plexuses. In normal rat brains, microglia do hardly express MHC class II antigens that were remarkably increased in number and staining intensity when the rats were challenged with LTA. Moreover, using the intracerebral injection of LTA to evaluate the direct effect of LTA on developing microglia, we showed that ramified microglia labelled with OX-42 or ED-1 progressively retracted their processes then became amoeboid form, indicating that microglia were activated in response to LTA. The evidence was strongly confirmed by the significant appearance of numerous OX-6 positive microglia after LTA treatment, in contrast to the saline treatment, only few microglia expressed MHC class II molecules. Similar responses of microglia to LTA were also evidenced in cultured microglia. In this in vitro study, LTA-stimulated microglia responded with a rounding-up profile and an enhanced expression of immune molecules with dose.
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