TABLE 1.

Effect of IFN-γ on the production of NO by control or by C. burnetii phase II-infected BMMφ or PMφ

Host cell	Production of NO (μM nitrite/105 macrophages/24 h ± sd)
	Uninfected		Infecteda
	No addition	With IFN-γ	No addition	With IFN-γ
BMMφ	0	0	1.8 ± 0.08	12.3 ± 0.20
PMφ	1.6 ± 0.04	4.1 ± 0.41	6.6 ± 0.20	16.9 ± 0.40

^aMacrophages were infected with C. burnetii for 24 h, and nitrite was measured in the culture supernatants. NO production was inferred from the nitrite content of culture supernatants. Cells were exposed to IFN-γ or to control medium for the duration of the infection.