• Vaccine Name: E. histolytica Eh29 protein vaccine
• Target Pathogen: Entamoeba histolytica
• Target Disease: Amoebiasis
• Vaccine Ontology ID: VO_0011450
• Type: Subunit vaccine
• Status: Research
• Antigen: E. histolytica alkyl hydroperoxide reductase Eh29
• gEh29 gene engineering:
  • Type: Recombinant protein preparation
  • Description: The full coding region of the gEh29 gene which encodes Eh29 (GenBank Accession No. X70996.1) was amplified by PCR and the 0.7 Kb amplicon was cloned into the expression vector pRSET-A (Invitrogen, CA, USA) following standard methods. After transformation into Escherichia coli BL21 (DE3) pLysS (Stratagene, CA, USA) positive clones were selected on ampicillin and chloramphenicol and were induced for expression of amino-terminal His-tagged Eh29 by incubation with 2 mM IPTG (Carrero et al., 2010).
  • Detailed Gene Information: Click Here.
• Adjuvant:
  • Adjuvant name:
  • VO adjuvant ID: VO_0000142
• Immunization Route: Intraperitoneal injection (i.p.)

Mouse Response

• Host Strain: C3H/HeJ
• Vaccination Protocol: Mice were divided into seven groups of 10 animals. Two groups were left unimmunized. The remaining five groups were immunized using Eh29 combined with CT (Eh29 + CT), Eh29–CTxB fusion protein, CT alone, CTxB alone, or ARF combined with CT (ARF + CT). Mice were immunized orally with a dose of the relevant protein solution on days 1, 7, and 21 using a plastic cannula (standard wall spaghetti tubing; Chemplast Inc., USA). The protein solutions were prepared in 0.2 M NaHCO3, pH 8.3 such that one dose contained 100 μg of either recombinant Eh29, Eh29–CTxB or ARF, and 10 μg of commercial CT or CTxB, as pertinent. Additionally, on day 14, all immunized groups received an intraperitoneal boost with 25 μg of the corresponding recombinant protein emulsified in incomplete Freund’s adjuvant. The groups receiving only CT or CTxB were boosted with adjuvant emulsified in PBS (Carrero et al., 2010).
• Challenge Protocol: On day 27 all mice (except those from one of the unimmunized groups) were infected intracecally with E. histolytica trophozoites recovered after three passages from hamster liver abscesses (Carrero et al., 2010).
• Efficacy: 80% of C3H/HeJ mice immunized with Eh29 administered in combination with a subclinical dose of whole cholera toxin, but not as an Eh29-CTxB fusion, showed no evidence of infection in tissue sections harvested following intracecal challenge with virulent E. histolytica trophozoites. These results suggest that Eh29 is capable of inducing protective anti-amoebic immune responses in mice following oral immunization and could be used in the development of oral vaccines against amoebiasis (Carrero et al., 2010).