Table 4.

Susceptibility of M. avium clones to the effect of nitric oxide

M. avium strain	No. of c.f.u. (ml macrophage lysate)−1*
	1 h	24 h
		−N-MA	+N-MA
WT (MAC 104)	6.4±0.3×105	8.3±0.3×105	8.7±0.5×105
STM1	2.0±0.4×105	8.1±0.3×104	8.5±0.6×104
STM2	4.4±0.2×105	7.6±0.3×104	8.1±0.2×104
STM3	5.2±0.5×105	4.1±0.3×105	3.8±0.4×105
STM4	2.6±0.2×105	1.0±0.3×105	9.8±0.2×105
STM5	3.4±0.2×105	9.8±0.3×104	1.0±0.4×105
STM6	3.9±0.5×105	2.8±0.4×105	2.7±0.6×105
STM8	3.8±0.2×105	8.3±0.3×104	7.6±0.5×104
STM10	4.6±0.3×105	4.1±0.5×104	1.6±0.3×105†
STM11	2.5±0.5×105	7.8±0.4×104	1.2±0.6×105†

*RAW 246.7 macrophage monolayers were infected for 1 h with M. avium, washed, and all of the wells were treated with IFN-γ and with 100 μM N-methylarginine. The monolayers were lysed after 24 h and the intracellular bacteria quantified. The experiments were repeated three times.

†P<0.05 compared with the number of bacteria at 24 h without N-methylarginine.