Growth of <i>M. leprae</i> and granulomatous response in infected FP.

<p>(A) <i>M. leprae</i> shows a similar growth profile in control mice and mice with single or combined deficiencies in IL-10 or NOS2. B6 (black circles), IL-10−/− (inverted triangles), NOS2−/− (diamonds), and 10NOS2−/− (triangles) mice were infected in each hind FP with 6×10³ viable <i>M. leprae</i>. At 3, 6, and 12 months, the number of AFB per FP was determined. Each symbol represents one mouse. The threshold of counting ability is 4.8×10³ AFB per FP. (B) Histological examination (hematoxylin and eosin stains) of <i>M. leprae</i>-infected FP at 6 months post infection. In B6 mice, minimal interstitial infiltrates of mononuclear cells can be seen between muscles in the ventral portion of the FP (bottom of figure). In IL-10−/− FP, more extensive mononuclear cell infiltrates are seen in the subcutis as well as greatly expanded granulomatous inflammation that has replaced approximately 25% of the total muscle mass. In NOS2−/− FP, granulomatous inflammation has replaced nearly 50% of the muscle mass, as is also seen in 10NOS2−/−. Experiment shown is representative of two independent experiments. *<i>p</i>≤0.05; **<i>p</i>≤0.01.