• Vaccine Name: E. histolytica Gal/GalNAc lectin protein vaccine
• Target Pathogen: Entamoeba histolytica
• Target Disease: Amoebiasis
• Vaccine Ontology ID: VO_0011451
• Type: Subunit vaccine
• Status: Research
• Antigen: E. histolyica Gal/GalNAc lectin
• Gal/GalNAc lectin gene engineering:
  • Type: Recombinant protein preparation
  • Description: The native E. histolytica Gal/GalNAc lectin was purified from strain HM1:IMSS trophozoites grown under axenic conditions as described previously [5]. A large fragment of the Gal/GalNAc lectin heavy subunit spanning amino acids 578–1154 (“LecA”) was cloned into a pRSET-A vector (Invitrogen, Carlsbad, CA) with a kanamycin resistance gene and expressed in E. coli. The E. coli cells were lyzed by sonication and isolated inclusion bodies were denatured in inclusion body solubilization reagent (Pierce, Rockford, IL) (Houpt et al., 2004).
  • Detailed Gene Information: Click Here.
• Adjuvant:
  • Adjuvant name:
  • VO adjuvant ID: VO_0000139
• Adjuvant:
  • Adjuvant name:
  • VO adjuvant ID: VO_0000142
• Immunization Route: Intraperitoneal injection (i.p.)

Mouse Response

• Host Strain: C3H/HeJ
• Vaccination Protocol: Mice were immunized with a combined intranasal and intraperitoneal regimen over 6–9 weeks. Intranasal immunizations used 10 μg of antigen and 1 μg of cholera toxin (Sigma) administered intranasally in 20 μl of PBS into C3H mice under isoflurane anesthesia. Intraperitoneal immunizations used 15 μg of antigen emulsified in equal volumes of either complete (CFA) or incomplete Freund’s adjuvant (IFA) (Gibco, Grand Island, NY) injected via 20 gauge syringe. The lectin-1 trial utilized 150 μl of complete Freund’s adjuvant, the week 4 immunization of the lectin-2 trial two utilized 100 μl of CFA, and all other i.p. immunizations utilized 150 μl of incomplete Freund’s adjuvant. Sham-immunized mice from each trial were administered an identical regimen of PBS with adjuvant (Houpt et al., 2004).
• Challenge Protocol: Mice were challenged intracecally with trophozoites 2 weeks after the final immunization (Houpt et al., 2004).
• Efficacy: Vaccination prevented intestinal infection with efficacies of 84 and 100% in the two native lectin trials and 91 and 34% in the two LecA trials. Results show for the first time that immunization with the Gal/GalNAc lectin can prevent intestinal amebiasis in mice (Houpt et al., 2004).