IL-6 alters the polarization of AAMs in a dose- and time-dependent manner.

<p>(A) At least 1 ng/mL of IL-6 (48 h) is required to amplify an AAM phenotype. (B) Increased arginase activity is apparent in AAMs (IL-4+IL-13 treated) 24 h post-cytokine treatment, whereas AAM differentiated in the presence of IL-6 (AAM(IL-6)) shows increased arginase activity after 12 h that is enhanced further at 24 h post-cytokine (n = 4), and expression of markers indicative of a murine AAM phenotype is prolonged in AAM(IL-6) compared to time-matched AAMs (C & D, n = 3-4). (E) IFNγ or TNFα (both 10 ng/mL) treatment does not enhance AAM polarization in the same way that IL-6 does (n = 3) (data are mean ± SEM; *, #, **, p<0.05 compared to MØ, AAMs and 0–0.1 ng/mL IL-6 respectively; U, units).