Ubiquitin of Entamoeba histolytica induces antibody response in patients with invasive amoebiasis

Abstract

Entamoeba histolytica causes amoebic liver abscess (ALA) in humans. The injury of target cells by E. histolytica includes processes controlled by the ubiquitin Ehub. Previously, we found immunodominance of Ehub glycan moieties using immunized rabbits. In this work, we analysed dominance of antibodies to the glycoprotein Ehub in the sera from 52 patients with ALA. Controls were sera from 20 healthy people living in endemic areas with a high seroprevalence of antibodies to amoebas, and 20 patients with alcoholic hepatitis (AH) to rule out the cross‐reaction of Ehub with autoantibodies induced by liver damage. Antigens were trophozoite extract, glycoprotein Ehub and the recombinant protein E. histolytica recombinant ubiquitin (rEhub). The sera from healthy volunteers and patients with AH do not have antibodies to glycoprotein Ehub. Surprisingly, only the antibodies from patients with ALA recognized the glycoprotein Ehub, and some sera gave a faint reaction with the recombinant protein, especially because evolutionarily, the ubiquitin is conserved between species. This is the first report demonstrating that antibodies to ubiquitin Ehub are induced exclusively in patients with invasive amoebiasis, and the antibody response is mainly to the glycoprotein, indicating glycans are immunodominant. Inhibitors of the Ehub glycans could be potential treatment for amoebiasis by selectively damaging trophozoites.

Amebic liver abscess by Entamoeba histolytica

“…For surgical treatment, a laparoscopic approach imposes the least physical burden resulting from the laparotomy[ 46 ]. According to the latest research results, ubiquitin Ehub antibodies are induced solely in patients with ALA or other invasive amoebiasis, and the antibody response is mainly to the glycoprotein, indicating that the glycans are immunodominant[ 59 ]. Therefore, Ehub glycan inhibitors hold potential as an amoebiasis treatment through selective damage to trophozoites[ 59 ].…”

Entamoeba histolytica: Membrane and Non-Membrane Protein Structure, Function, Immune Response Interaction, and Vaccine Development

“…Notably, the ubiquitin's glycan moieties are immunodominant and induce IgG. Furthermore, antibodies to the ubiquitin Ehub are induced exclusively in patients with invasive amoebiasis and mainly to glycoprotein [73]. It indicates that glycan is immunodominant and could be a potential target for diagnostic tests, drugs, and vaccines to combat parasitic diseases [69,73].…”