Immunocompetent Acanthamoeba spp.-infected mice at the beginning of infection showed higher activity of MMP-9 in the cerebral cortex compared to the uninfected group of mice, whereas immunosuppressed Acanthamoeba spp.-infected mice at 24 dpi showed lower MMP-9 levels compared to immunosuppressed uninfected animals. Here, MMP9 is linked to infection.