Protection of gerbils from amebic liver abscess by immunization with recombinant Entamoeba histolytica 29-kilodalton antigen

Infect Immun. 1995 Feb;63(2):472-7. doi: 10.1128/iai.63.2.472-477.1995.

Abstract

The goal of our study was to obtain a highly conserved Entamoeba histolytica recombinant antigen for study as a subunit amebiasis vaccine. We screened a Uni-Zap cDNA library of E. histolytica (strain HM1:IMSS) with human immune sera and isolated a dominant 804-bp cDNA clone. A 33-kDa fusion protein expressed from the cDNA clone was determined by monoclonal antibody binding, DNA hybridization, and nucleotide sequence to be the complete E. histolytica 29-kDa antigen. Serum antibodies to the recombinant protein were detected by enzyme-linked immunosorbent assay in 80% of subjects from Egypt and South Africa with amebic liver abscess. Similar results were found with the native 29-kDa protein. Native and recombinant 29-kDa antigens induced proliferation of lymphocytes harvested from patients with amebic liver abscess (P < 0.01 compared with controls). Intraperitoneal immunization of gerbils with the recombinant fusion protein (10 micrograms) with Titermax adjuvant elicited an antigen-specific serum immunoglobulin G antibody response and was partially protective (54%) against intrahepatic challenge with 5 x 10(5) virulent axenic trophozoites (strain HM1:IMSS). In summary, the recombinant form of the E. histolytica 29-kDa antigen demonstrated serologic specificity for amebic liver abscess, exhibited conserved T-cell epitopes, and was effective as a subunit vaccine in an experimental animal model of amebic liver abscess.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Animals
  • Antigens, Protozoan / immunology*
  • Cloning, Molecular
  • Entamoeba histolytica / immunology*
  • Gerbillinae
  • Humans
  • Liver Abscess, Amebic / immunology
  • Liver Abscess, Amebic / prevention & control*
  • Male
  • Recombinant Proteins
  • Vaccines, Synthetic

Substances

  • Antigens, Protozoan
  • Recombinant Proteins
  • Vaccines, Synthetic