Figure 7: M2 macrophages mediate immunity to Nb reinfection.

(a) Number of macrophages in the lung in primary (Nb) or i.v.-reinfected mice (Nb+Nb) with N. brasiliensis (n=5, mean+s.e.m., representative of three independent experiments, t-test). (b) Differential larvae number in the airways (dark grey) or lung parenchyma (light grey) of C57BL/6 mice after primary (Nb) or i.v. reinfection (Nb+Nb). Bone marrow-derived M2 from C57BL/6 or Stat6^−/− mice were adoptively transferred by intranasal inoculation before infection (n=5 mice, mean+s.e.m., representative of two independent experiments, ANOVA). (c) Confocal imaging of lungs 1 day after i.v. inoculation of CFSE-labelled Nb and 2 days after intranasal transfer with PKH26-labelledbone marrow-derived M2 or M1 macrophages. Images were acquired on live lung tissue, 24 h after infection. Maximum projection of 30 z stacks representing an overall 100-μm depth. Scale bar, 100 μm (d) Differential larvae number in the airways or lung parenchyma of mice treated with the arginase inhibitor BEC before primary or i.v. reinfection (n=5 mice, mean+s.e.m., representative of two independent experiments, ANOVA). (e) MFI of RELMa, STAT6P and arginase in interstitial macrophages from mice treated with the arginase inhibitor BEC before i.v.-reinfection infection (n=5 mice, mean+s.e.m., representative of two independent experiments, ANOVA) (f) Differential larvae number in the lungs at day 2 post-primary (Nb) or i.v. reinfection (Nb+Nb), and in mice treated with clodronate liposomes (CL) or anti-F4/80 (Hb-198) antibody or matched isotype control (n=5 mice, representative of two independent experiments, ANOVA). (g) Number of alveolar macrophages (AM, CD45⁺ F4/80^int CD11c^high SiglecF⁺), interstitial macrophages (IM, CD45⁺ F4/80^high CD11c^low SiglecF⁻) and eosinophils (CD45⁺ F4/80^int CD11c⁻ SiglecF⁺) after i.v. reinfection and with anti-F4/80 administration before reinfection (n=4 mice, mean+s.e.m., representative of two independent experiments, ANOVA). (h) Number of red blood cells in the BALF of mice after primary (Nb) and secondary infection (Nb+Nb) or with anti-F4/80 treatment before i.v. reinfection (Nb+αF4/80+Nb; n=5 mice, mean+s.e.m., ANOVA). NS, non-significant; P>0.05; *P<0.05; **P<0.01; ***P<0.001; ****P<0.0001.