title: Use of in vitro assays to determine effects of human serum on biological characteristics of Acanthamoeba castellanii.
abstract: Normal human serum inhibits Acanthamoeba (encephalitis isolate) binding to and cytotoxicity of human brain microvascular endothelial cells, which constitute the blood-brain barrier. Zymographic assays revealed that serum inhibits extracellular protease activities of acanthamoebae. But it is most likely that inhibition of specific properties of acanthamoebae is a consequence of the initial amoebicidal-amoebistatic effects induced by serum. For example, serum exhibited amoebicidal effects; i.e., up to 50% of the exposed trophozoites were killed. The residual subpopulation, although viable, remained static over longer incubations. Interestingly, serum enhanced the phagocytic ability of acanthamoebae, as measured by bacterial uptake. Overall, our results demonstrate that human serum has inhibitory effects on Acanthamoeba growth and viability, protease secretions, and binding to and subsequent cytotoxicity for brain microvascular endothelial cells. Conversely, Acanthamoeba phagocytosis was stimulated by serum.
authors.affiliation: School of Biological and Chemical Sciences, Birkbeck, College University of London, London WC1E 7HX, England.
authors.forename: James
authors.initials: J
authors.lastname: Sissons
authors.forename: Selwa
authors.initials: S
authors.lastname: Alsam
authors.forename: Monique
authors.initials: M
authors.lastname: Stins
authors.forename: Antonio Ortega
authors.initials: AO
authors.lastname: Rivas
authors.forename: Jacob Lorenzo
authors.initials: JL
authors.lastname: Morales
authors.forename: Jane
authors.initials: J
authors.lastname: Faull
authors.forename: Naveed Ahmed
authors.initials: NA
authors.lastname: Khan
mesh_terms: D048248:Acanthamoeba castellanii / Q000254:growth & development / Q000378:metabolism / Q000472:pathogenicity / Q000502:physiology*; D001921:Brain / Q000098:blood supply; D002448:Cell Adhesion; D016923:Cell Death; D042783:Endothelial Cells / Q000166:cytology / Q000469:parasitology; D006801:Humans; D010447:Peptide Hydrolases / Q000378:metabolism; D010587:Phagocytosis; D015800:Protozoan Proteins / Q000096:biosynthesis; D044967:Serum / Q000502:physiology*
chemical_list: D015800:Protozoan Proteins; D010447:Peptide Hydrolases