Establishment of human microglial cell lines after transfection of primary cultures of embryonic microglial cells with the SV40 large T antigen.

Four continuous cell lines of human microglial cells were obtained by transfection of enriched cultures of human embryonic brain-derived macrophages with a plasmid encoding for the large T antigen of SV40. The transformed cells had the macrophagic characteristics of adherence and intra-cytoplasmic non-specific esterase activity. They could phagocytize zymosan particles but the phagocytic activity remained low. They expressed several macrophagic antigens but not the monocytic markers CD14, CD4, CD68/Ki-M6 and CD11c. The cells could be activated to express class II major histocompatibility complex antigens after interferon-gamma activation. Finally, interleukin-6 was produced spontaneously by the cells and this production was further increased after interleukin-1 alpha stimulation.