Entamoeba dispar: molecular characterization of the galactose/N-acetyl-d-galactosamine lectin.
Amebiasis contributes to approximately 50 million cases of life-threatening dysentery worldwide. Comparison of the lectins from Entamoeba histolytica (pathogenic) and Entamoeba dispar (nonpathogenic) was undertaken to elucidate the differential roles of this molecule in invasion versus colonization. Surface lectin was less abundant on axenic E. dispar than on axenic E. histolytica, commensurate with differences in lectin (heavy and light subunits) RNA when assessed by semiquantitative RT-PCR. The 1G7 epitope, which falls within the immunodominant and immunoprotective cysteine-rich region (480-900), was absent on axenic E. dispar. Indirect immunofluorescence, transient transection of COS7, and immunoprecipitation demonstrated that the 1G7 epitope was conserved in the nonpathogenic lectin homologue but not exposed on live E. dispar trophozoites. Hgl2 (E. histolytica) and Dhgl2 (E. dispar) lectin homologues demonstrated comparable high-affinity binding to multivalent GalNAc(19) BSA. These data provide evidence for relative gene and conformational regulation of the E.dispar lectin.
Pillai
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Division of Infectious Diseases, Toronto General Hospital, Toronto, M5G 2C4, Canada.
Kobayashi
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Kain
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D000818:Animals; D015153:Blotting, Western; D002448:Cell Adhesion; D003720:Densitometry; D004747:Entamoeba / Q000737:chemistry / Q000235:genetics*; D004797:Enzyme-Linked Immunosorbent Assay; D000939:Epitopes / Q000737:chemistry / Q000235:genetics / Q000276:immunology; D005434:Flow Cytometry; D019084:Fluorescent Antibody Technique, Indirect; D015971:Gene Expression Regulation, Enzymologic; D037102:Lectins / Q000737:chemistry / Q000235:genetics* / Q000276:immunology; D008562:Membrane Glycoproteins / Q000737:chemistry / Q000235:genetics* / Q000276:immunology; D011233:Precipitin Tests; D015800:Protozoan Proteins / Q000737:chemistry / Q000235:genetics* / Q000276:immunology; D012333:RNA, Messenger / Q000032:analysis; D020133:Reverse Transcriptase Polymerase Chain Reaction
D000939:Epitopes; D037102:Lectins; D008562:Membrane Glycoproteins; D015800:Protozoan Proteins; D012333:RNA, Messenger; C052452:galactose inhibitable adherence protein, Entamoeba histolytica; C078014:N-acetylgalactosamine inhibitable lectin 35-kDa subunit, Entamoeba histolytica