Table 1.

Levels of IL-6 measured by ELISA in culture supernatant from peritoneal macrophages cultured for 48 h with and without splenic NK cells and with and without 1 µg/ml LPS. Peritoneal macrophages from CD40−/– mice were also used, as well as splenic NK cells from CD154−/– and IFN-γ−/– mice

	MΦ (IL-6 pg/ml)	MΦ + ΝΚ (IL-6 pg/ml)	MΦ + LPS (IL-6 pg/ml)	MΦ + NK + LPS (IL-6 pg/ml)
WT	260 ± 60	87 ± 17	14100 ± 1800*	8500 ± 300*
CD40–/–	230 ± 40	370 ± 100	9800 ± 800*	9500 ± 100*
CD154–/–	290 ± 90	220 ± 60	10600 ± 1100*	7100 ± 1300*
IFNγ–/–	460 ± 210	400 ± 140	15900 ± 1600*	13400 ± 1700*

MΦ, peritoneal macrophages; NK, splenic NK cells; LPS, lipopolysaccharide; WT, wild type C57BL/6 mice; n = 6 per group, averaged from separate repeated experiments

^*P < 0·05 LPS versus no LPS.