The influence of culture conditions and serum lipids on interleukin-1 production by human monocytes.

Reliable assessment of IL-1 production by human monocytes is critically dependent on the methods for isolation and culture of these cells. In the present study, the quality of pipettes and the preparation of Ficoll-Isopaque appear to be crucial for IL-1 production from both LPS-stimulated and unstimulated monocytes. Different brands and lots of polystyrene culture wells give rise to great variation in IL-1 production. When carefully prepared, hydrophobic teflon membranes, to which mononuclear phagocytes poorly adhere, are used as the culture substrate, stimulation of IL-1 production is observed. The HLA DR3 haplotype of the monocyte donors did not influence IL-1 production. The addition of normal human AB serum to the cultures usually increases IL-1 production, although strong inhibition of both unstimulated and LPS-stimulated IL-1 production was also observed after addition of a diet-induced hyperlipemic AB serum. This inhibition was not due to cholesterol, chylomicrons, high- or low-density lipoproteins. When monocytes were cultured at different temperatures, the only abnormality found was a decrease of cell-associated IL-1 at 41 degrees C.