title: Differentiation of Entamoeba histolytica: a possible role for enolase.
abstract: The study of the encystation process of Entamoeba histolytica has been hampered by the lack of experimental means of inducing mature cysts in vitro. Previously we have found that cytoplasmic vesicles similar to the encystation vesicles of Entamoeba invadens are present in E. histolytica trophozoites only in amebas recovered from experimental amebic liver abscesses. Here we report that a monoclonal antibody (B4F2) that recognizes the cyst wall of E. invadens also identifies a 48 kDa protein in vesicles of E. histolytica trophozoites recovered from hepatic lesions. This protein is less expressed in trophozoites continuously cultured in axenical conditions. As previously reported for E. invadens, the B4F2 specific antigen was identified as enolase in liver-recovered E. histolytica, by two-dimensional electrophoresis, Western blot and mass spectrometry. In addition, the E. histolytica enolase mRNA was detected by RT PCR. The antigen was localized by immunoelectron microscopy in cytoplasmic vesicles of liver-recovered amebas. The B4F2 antibody also recognized the wall of mature E. histolytica cysts obtained from human samples. These results suggest that the enolase-containing vesicles are produced by E. histolytica amebas, when placed in the unfavorable liver environment that could be interpreted as an attempt to initiate the encystation process.
authors.affiliation: Department of Infectomics and Molecular Pathogenesis, Center for Research and Advanced Studies, Mexico City, Mexico.
authors.forename: Norma Cristina
authors.initials: NC
authors.lastname: Segovia-Gamboa
authors.forename: Patricia
authors.initials: P
authors.lastname: Talamás-Rohana
authors.forename: Amelia
authors.initials: A
authors.lastname: Ángel-Martínez
authors.forename: Febe Elena
authors.initials: FE
authors.lastname: Cázares-Raga
authors.forename: Arturo
authors.initials: A
authors.lastname: González-Robles
authors.forename: Verónica Ivonne
authors.initials: VI
authors.lastname: Hernández-Ramírez
authors.forename: Adolfo
authors.initials: A
authors.lastname: Martínez-Palomo
authors.forename: Bibiana
authors.initials: B
authors.lastname: Chávez-Munguía
mesh_terms: D000818:Animals; D000911:Antibodies, Monoclonal / Q000276:immunology; D015153:Blotting, Western; D006224:Cricetinae; D022162:Cytoplasmic Vesicles / Q000201:enzymology; D015180:Electrophoresis, Gel, Two-Dimensional; D004591:Electrophoresis, Polyacrylamide Gel; D004748:Entamoeba histolytica / Q000201:enzymology* / Q000235:genetics / Q000502:physiology; D004797:Enzyme-Linked Immunosorbent Assay; D015971:Gene Expression Regulation, Enzymologic; D005849:Gerbillinae; D006801:Humans; D008099:Liver / Q000469:parasitology; D008297:Male; D013058:Mass Spectrometry; D008856:Microscopy, Fluorescence; D016253:Microscopy, Immunoelectron; D010751:Phosphopyruvate Hydratase / Q000235:genetics / Q000276:immunology / Q000378:metabolism*; D012333:RNA, Messenger / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction
chemical_list: D000911:Antibodies, Monoclonal; D012333:RNA, Messenger; D010751:Phosphopyruvate Hydratase