Figure 1. Infection by Aspergillus fumigatus induces markers of Alternatively Activated Macrophages in the lung.

(A) Mice were infected with 100 cfu of K. pneumoniae or 50×10⁶ resting conidia (RC) of A. fumigatus given intratracheally and lungs were harvested after 4 days (Klebsiella) or 48 hours (Aspergillus) of infection for total RNA extraction. RT-PCR was performed to measure mRNA expression of Arg1, Fizz1 and NOS2. The results shown were generated using RNA from 1 mouse (n = 4) with the PCR products in the different lanes generated with increasing dilutions of cDNA. β-actin expression was used as an internal control. mRNA expression corresponding to the various genes in infected lungs was compared with that expressed in the lungs of uninfected mice. Mice were infected with 50×10⁶ RC or given PBS intratracheally (uninfected group). The expression of Arg1, NOS2 and Fizz1 was analyzed by quantitative RT-PCR (B) at 6, 12 and 24 hours (C) at 48 and 96 hours p. i. The fold increase in expression for each gene is expressed relative to that in uninfected mice using Gus-β expression for normalization. Values shown are mean ± SEM. (D) Arginase activity expressed as U/mg protein was measured in protein extracts made from lungs 48 and 96 hours p. i. (E) Immunoblotting of YM1 was performed using protein extracts made from lungs using anti-YM1 antibody. β-actin expression was examined as loading control and the intensity of YM1 band was quantified relative to that of β-actin. Data shown are representatives of two independent experiments (n = 4–6 mice in each group).