Fig. 1. In vitro release of tumour necrosis factor alpha (TNF) from peritoneal macrophages in Balbc mice. TNF was measured in the cell culture supernatants after 24 h of stimulation with lipopolysaccharide (LPS) (1 µg ml^–1). The control is supernatant from non-stimulated cultures. The results are presented as the mean + S.E.M. of three independent experiments. F-LPS, fluorescein-labelled LPS.