We investigated the mRNA expression of the various complement components in cultured mouse microglia and astrocytes by the reverse transcription and polymerase chain reaction. C1q, C2, C3, and C4 mRNAs were detected in microglial cultures. C3 and C4 mRNAs were found in astrocyte cultures. Microglia showed enhanced expression of C2, C3, and C4 mRNAs when they were treated with lipopolysaccharide. Much higher expression of C1q, C2, C3, and C4 mRNAs was detected in microglia after stimulation with interferon-gamma. Our data suggest that microglia and astrocytes may produce some of the complement components also in vivo, which can be facilitated in certain infectious and inflammatory diseases in the central nervous system.
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