The activation status of the macrophage directly influences cryptococcal killing.

<p>In the presence of Th1-type cytokine IFN-γ, macrophages polarize to a classically activated (M1) phenotype. These macrophages produce reactive oxygen species (ROS) and NO, which contribute to their anticryptococcal activity. However, when the Th2-type cytokines IL-4 and/or IL-13 are more prevalent, macrophages polarize toward an alternatively activated (M2) phenotype. M2 macrophages do not have anticryptococcal activity and are permissive to intracellular proliferation of <i>C</i>. <i>neoformans</i>.