Immunopathogenicity of Acanthamoeba spp. in the Brain and Lungs

Abstract

Free-living amoebas, including <i>Acanthamoeba</i> spp., are widely distributed in soil, water, and air. They are capable of causing granulomatous amebic encephalitis, <i>Acanthamoeba</i> pneumonia, <i>Acanthamoeba</i> keratitis, and disseminated acanthamoebiasis. Despite low occurrence worldwide, the mortality rate of <i>Acanthamoeba</i> spp. infections is very high, especially in immunosuppressed hosts. <i>Acanthamoeba</i> infections are a medical problem, owing to limited improvement in diagnostics and treatment, which is associated with incomplete knowledge of pathophysiology, pathogenesis, and the host immune response against <i>Acanthamoeba</i> spp. infection. The aim of this review is to present the biochemical and molecular mechanisms of <i>Acanthamoeba</i> spp.-host interactions, including the expression of Toll-like receptors, mechanisms of an immune response, the activity of metalloproteinases, the secretion of antioxidant enzymes, and the expression and activity of cyclooxygenases. We show the relationship between <i>Acanthamoeba</i> spp. and the host at the cellular level and host defense reactions that lead to changes in the selected host's organs.