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Entamoeba histolytica

Table of Contents
  1. General Information
    1. NCBI Taxonomy ID
    2. Disease
    3. Introduction
    4. Microbial Pathogenesis
    5. Host Ranges and Animal Models
    6. Host Protective Immunity
  2. Vaccine Related Pathogen Genes
    1. CEL-170/4 (Protective antigen)
    2. Gal/GalNAc lectin (Protective antigen)
    3. GEh29 (Protective antigen)
    4. SREHP (Protective antigen)
  3. Vaccine Information
    1. E. histolytica CEL-170/4 protein vaccine
    2. E. histolytica Eh29 protein vaccine
    3. E. histolytica Gal/GalNAc lectin protein vaccine
    4. E. histolytica SREHP protein vaccine
  4. References
I. General Information
1. NCBI Taxonomy ID:
5759
2. Disease:
Amoebiasis
3. Introduction
Entamoeba histolytica is an anaerobic parasitic protozoan, part of the genus Entamoeba. Predominantly infecting humans and other primates, E. histolytica is estimated to infect about 50 million people worldwide. Many older textbooks state that 10% of the world population is infected, but these figures predate the recognition that at least 90% of these infections were due to a second species, E. dispar. Mammals such as dogs and cats can become infected transiently, but are not thought to contribute significantly to transmission.

The active (trophozoite) stage exists only in the host and in fresh loose faeces; cysts survive outside the host in water, soils and on foods, especially under moist conditions on the latter. The cysts are readily killed by heat and by freezing temperatures, and survive for only a few months outside of the host. When cysts are swallowed they cause infections by excysting (releasing the trophozoite stage) in the digestive tract. The trophozoite stage is readily killed in the environment and cannot survive passage through the acidic stomach to cause infection. Symptoms can include fulminating dysentery, bloody diarrhea, weight loss, fatigue, abdominal pain, and amoeboma (Wiki: Entamoeba histolytica).
4. Microbial Pathogenesis
The amoeba can actually 'bore' into the intestinal wall, causing lesions and intestinal symptoms, and it may reach the blood stream. From there, it can reach different vital organs of the human body, usually the liver, but sometimes the lungs, brain, spleen, etc. A common outcome of this invasion of tissues is a liver abscess, which can be fatal if untreated. Ingested red blood cells are sometimes seen in the amoeba cell cytoplasm (Wiki: Entamoeba histolytica).
5. Host Ranges and Animal Models
Other than infecting humans, mammals such as dogs and cats can become infected transiently, but are not thought to contribute significantly to transmission (Wiki: Entamoeba histolytica).
6. Host Protective Immunity
It has been shown that amoeba-specific sIgA antibodies are capable of blocking parasite adherence to target cells, preventing cytotoxic activity (Carrero et al., 2010).
1. CEL-170/4
  • Gene Name : CEL-170/4
  • Sequence Strain (Species/Organism) : Entamoeba histolytica
  • VO ID : VO_0011326
  • NCBI Protein GI : 401088
  • Taxonomy ID : 5759
  • Gene Strand (Orientation) : ?
  • Protein Name : 170 kDa surface lectin
  • Protein Length : 1285
  • Protein Note : 170 kDa surface lectin. /FTId=PRO_0000022350.
  • Protein Sequence : Show Sequence
    >gi|401088|sp|P23502.2|SL17_ENTHI RecName: Full=170 kDa surface lectin; Flags: Precursor
    MKLLLLNILLLCCLADKLNEFSADIDYYDLGIMSRGKNAGSWYHSYTHQYDVFYYLAMQPWRHFVWTTCE
    TTKGNKECYKYIINEDHNLNAQQLNNIKNLDKQDFCQKEYAYPIEKYEVDWDNVPVDEQQIESVDINGKT
    CFKYAAKRPLAYVYLNTKMTYATKTEAYDVCRMDFIGGRSITFRSFNNENKDFIDQYNTNTTSKCIIDVH
    KNNVNTHLAIILGITDSTVIKSLQENLSLLSQLKQSRVTLYYLKDDSYATDNIKLKDLKYETLVKYTAGQ
    GQVDPLVNQAKNDLFKMISDKKIKRGTMVVLMDNALGSEFNAETEFDRKNISVHTVVLNRNKDSKITYSA
    LKLVSLGPHYHEFTSNSEVSTTIDELFKGIRANLTERCDRDKCSGFCDAMNRCTCPMCCENDCFYTSCDV
    ETGSCIPWPKAKPKAKKECPATCVGLYECKDLEGCVVTKYNASCEPKVKCMVPYCDDDNNLKEVCKQKAN
    CEADQKPSSDGYCWSYTCDETTGFCKKYKHGNLCTGKTTNCQEYVCDSEQRCTVQEKVCVKTSPYIEMSC
    YVAKCNLNTGMCENRLSCDTYSSCGGDSTGSVCKCDASTGNQCKCNKVENGNYCDSSKHEICDYTGDKPK
    CIVSECTEDLVRDGCLIKRCNKTSKTTYWENVDCSNTKIEFAQDGKSETMCKPYYSATCLNGQCVVQAVG
    DVSNVGCGYCSMGTDNVITYHDDCDSRKSQCGNFNGKCQPNGDNSYSCVFEKDKTSSKSDNDICAECSSL
    TCPADTTYRTYTYDSKTGTCKATVKPTPSCSVCEKGKFVEKSKDQKLERKVTLEDGKEYQYNIPKDCVNE
    QCIPRTYVDCLANDDNFGEIYKFYLPCQAYVTATYHYSSLFNLTSYKLHLPQSEEFMKEADKEAYCTYEI
    TTRECKTCSLTETKEKVEEIDLCAEETKNGGVPFKCKNNNCIIDPNFDCQPIECKIQEIVITEKDGIKTT
    TCKDGTKTTCDTNNKRIEDARKAFIEGKEGIEQVECASTVCQNDNSCPIIADVEKCNQNTEVDYGCKAMT
    GECDGTTYLCKFVQLTDDPSLDSEHFRTKSGVELNNACLKYKCVESKGSDGKITHKWEIDTERSNIDPKP
    RNPCETATCDQTTGETIYTKKTCTVSEEFPTITPNQGRCFYCQCSYLDGSSVLTMYGETDKEYYDLDACG
    NCRVWNQTDRTQQLNNHTECILAGEINNVGAIAAATTVAVVVVAVVVALIVVSIGLFKTYQLVSSAMKNA
    ITTTNENAEYVGADNEATNAATYNG
  • Molecule Role : Protective antigen
  • Molecule Role Annotation : Researcherse tested the ability of the galactose-specific adherence lectin of E. histolytica to elicit a protective immune response in conjunction with Freund's incomplete and complete adjuvants. Four independent trials demonstrated complete protection from amebic liver abscess formation in 67% of lectin-immunized gerbils. The gerbil antilectin antibodies were shown by Western immunoblotting to be directed to the heavy subunit (CEL-170/4) but not the light subunit of the lectin (Petri and Ravdin, 1991).
  • Related Vaccine(s): E. histolytica CEL-170/4 protein vaccine
2. Gal/GalNAc lectin
  • Gene Name : Gal/GalNAc lectin
  • Sequence Strain (Species/Organism) : Entamoeba histolytica HM-1:IMSS
  • VO ID : VO_0011323
  • NCBI Gene ID : 3404842
  • NCBI Protein GI : 67469085
  • Locus Tag : EHI_046650
  • Genbank Accession : DS571321
  • Protein Accession : XP_650534
  • Taxonomy ID : 294381
  • Gene Starting Position : 16307
  • Gene Ending Position : 19930
  • Gene Strand (Orientation) : -
  • Protein pI : 4.63
  • Protein Weight : 126939.55
  • Protein Length : 1207
  • Protein Note : transcript EHI_046650A
  • DNA Sequence : Show Sequence
    >ref|NW_001915036.1|:16307-19930 Entamoeba histolytica HM-1:IMSS scf_1104750517013, whole genome shotgun sequence
    ATTATCCATTGAAATTAGCATTTGTGGCATTATCATCTTTAGCTGTGAATTGTGGGTTATTCACAGTATT
    ATCAACAGTATTCTTTCTTGCAGAAATAACAATATCAACAGTTTGCTTAATTCCAATAGCAATAATTACC
    ATAACAACAACAATTACTGCAACAACAACTGCAACAGTGGTACCAGCAGCAATAGCAGCTGTATTATCAA
    CGTCTTGCCATAACAAACAAACAGCATCTTTATCAACCAATTCATCATTGATCTTACAATTACCACATGC
    ATCTAATGAGAATCTATGATCTGCATAATCAGAGTACATTGTTAAAATCCACCCACTTTCAGATTGTAAT
    GAACATTCACAATAGAAACAATTCTTAGCTGCTTTAGACATATTAGGGAATTGAATATCAATATCACATT
    GAACAAAATTAGTTTCAATTTCTCCTGTTTCTTTGTCACAATAAGCGTCTTGACATTTATTCTTATAGAG
    CAATGCTTTTTCATGTCCATCAATATTACTTGTCCATTTATGTGTTATCACTCCTTCAGTGATAGTTTCA
    ACACAGGTATAATTATAACATTTATCAGTACAATCCCTATCATTAGATGGCTCATCACTACATTTTGTAA
    ATTCCTTCTTGATACAATATCCTGTACTTGTATCACATTTACCTGTTAATGAAGCACACCCAACATCAGC
    AGTATTTGATGAACAAATAGAATCATCATACACACCACTACATTTTGGAATACTTCCAGAAGCATCACAA
    TTAGTTTTCATACAAATAACTTCTCCAGGTTTACTAGGAGGAAGTGATGGACAAATAGTGACATTAGTTG
    GTTCACAAAGTTGGGATGTTCCAGTCTTTACTTGAATGAAACAATTATTAGTTGGATTACAATCTCCTTC
    ATATTTACAATCCCCATCTGAACAAGTCATCTGATAAATATTTCCAGATGCATCTACTTGATTTGGACAT
    TTATCAACAAGAGTAGACTCTTTATCCATTCCACTACAATACTTACATAAACTTTTTACCTTTTCTTCGT
    TTGAATTCCATTCACATTTATATTCATCAAATGTTGTGCCAATAATTAATTTGTAATCAAGAACATCAAG
    ACATTTACTAGGGAAATTCTCATGTTTAGTACAATCAAATTCATCATCAATATGACAACTTCCATCACGA
    CATACATATGGAATACCATTTATATTCTTTTTATTAGTACAATCCATTTTAATAAGTTTAGCTGGGTCAA
    CAAGAATATTATCATATGAACAATACATACACTGACTATCTAAAATAACTTTTGATCCATCTTTTACAAT
    AACTTTACATTCTCCATTTGCATATTCCCATTCATAATATTGTTCACAATCACTTAATCTATCTTTGAAA
    AGATCTTTACAATCATATTCATCTGGTGCTTGACATTCTCCATCTTTACAAACAAATGGAATTCCTTGTG
    ATGTAGTCAAACCTTCACATTTATTAACAATTTCATTTCCATCACAAATTTTACATTCTTGAATTGCTTT
    ATCTGTAGTTACAAGTATACATTCTCTATTTCCACTACATACATAATTAGCATATCCATCACATTTTTCA
    GGTACTTTTTCTTTACATACATATTCCTCTTGGTCTACAACATATTGAGTCGTTCCATTAGCAGTATATT
    CTTTACAGACTTTTTTGTAACAACCTTCCCAAACAATATCATGTCCTTTAAGCTCTTCACAATTATCAAC
    ATTAATACATTTTGGATCCCCATCTGTATAATCACAAACTTCGCCATTAGTACATCCATTACTAGTATCA
    CATTTACATTGATATGATGTAGATGCATCACATCGACAATTTCCATTAACTTTCCCACACACTTTCATTC
    CAGAACTACATCCAACTAAATTCATAACACAATTTCCAGTTTCACTATCACATGTAGCTTCATAACATGG
    ATTTTCTTCATATGGAGATACTTTAATACATTTCTTTTCTTGAACCATACATGTTCCAGCAGAACAATAA
    TATTCTTCACACTTACTTGATAATTTAGGACAATAGCTAGATGATTGTAATGTATTTGGAATACATTCTC
    CATTTGTTCTATCACATGAATAAGTTCTACAAACAAATTTTTCTACTCCAGATTCAATAATTGAAGATGG
    CTTAATATCATCAGTACAATTACTTCTAAAAGCACAGTTGTTTCCTGAACAATAAGGCTCTAAACATTTA
    ACTGTTGAAACACATTTATTTTGTTCAATAGTACATCCAATATCTTCAACACATTTAGCTACACCTAAAC
    AACTTTCTGTTGTACATTTTCTTTTTTCAATTTTATGATCAGCACTTGGATAATAAACACATTCTCCATT
    TTCAGTATTACATGTTGTATAATAACATTCACTATGACAACACATTGGACATGTACAACGAGCCCCACCA
    TCACAAAATCCTTTACAAGTTTTTCTATCACATAATTCAGTATTATTTGCCATAATAGTATTATATAATT
    GTGGAAGAGAAGTGCTTAATGATGAAACAGATGATTTAAAGTAATGTTCCCCTTTATTAACTAATTCTTC
    AAGTTGATATTCTTCTTCAATTGATGAGTCTAAATTAAATACATAAAATGTAGTATTATGACTATAAAGA
    GTATTTAACATATTAGAAGCTTTTCCTGCATATTTACTGATATAAACAATATTCTTTCCTGCTTTTGAAG
    ACATTTGGTTATATACAGTTTCTATAGCTTTTGTTTCATTTCCTTTTCTCATAACAGTAATTCCATTTAA
    TACATTTTTAATATTATCCTTTGTTACTAATGAATCTGAATGATATGGATTTTGAGAGTTAATATAATAA
    GCGAATGAAGTATCATTTGGGAATAAATCAATCAAATAATTAACAATTGAACTAAATATATTTCTTAATG
    TATTAGTCATATCTAAATTAACAACAATACCAACCGCCATATTATTTGTTGGTGGTAAAACAGTAGAAGC
    ATGACATTTAGTAATATTATTATTTTTATAGTCAGTGATAAAATTATCAGAAAATTCTGAACTACTTCTA
    AATGTAATAACTTTACCTCCAATATATTCAAATCTACATGGTGACATTCCTTCTGCATATTTATTTGTTA
    CATCATATGTTTTTTCAAGAAAATATGCAGCTGTTAATGGTGGTTTAGCAGCATATTTATAACAAGTTAA
    TCCATTAATTGAAACAACTGGTAATTTAGAAGTATCTGATGGAATACGAGACCAATCCAATTGATATTCT
    CTAATAGGATATCCCATTTTCTTTCTACACATATTTTCTTCTTTTGTATCACTTTTATCACGGTCATAAT
    CTTGATTAAATATCATTTCAGTAAAATATTTACTTTGGTCTTTAGTAGGAAAATTACTATCAATAGTTGT
    CCATTCTAAATTTCTCCATGGTTGCATTGTTAAATAATAAAATACACTATACTTTTTATTTACACTTCTT
    GACCATGAAGCTGCATTTTTACCCATTCCCATTCTTCCTTTATCTTGGATATCTACAGTTCCAGAAAACT
    CATTTAAATTAATTCCTAAAGCAATTGAAGCATAAAATAATACCAAAATTATCA
  • Protein Sequence : Show Sequence
    >gi|67469085|ref|XP_650534.1| Gal/GalNAc lectin heavy subunit [Entamoeba histolytica HM-1:IMSS]
    MIILVLFYASIALGINLNEFSGTVDIQDKGRMGMGKNAASWSRSVNKKYSVFYYLTMQPWRNLEWTTIDS
    NFPTKDQSKYFTEMIFNQDYDRDKSDTKEENMCRKKMGYPIREYQLDWSRIPSDTSKLPVVSINGLTCYK
    YAAKPPLTAAYFLEKTYDVTNKYAEGMSPCRFEYIGGKVITFRSSSEFSDNFITDYKNNNITKCHASTVL
    PPTNNMAVGIVVNLDMTNTLRNIFSSIVNYLIDLFPNDTSFAYYINSQNPYHSDSLVTKDNIKNVLNGIT
    VMRKGNETKAIETVYNQMSSKAGKNIVYISKYAGKASNMLNTLYSHNTTFYVFNLDSSIEEEYQLEELVN
    KGEHYFKSSVSSLSTSLPQLYNTIMANNTELCDRKTCKGFCDGGARCTCPMCCHSECYYTTCNTENGECV
    YYPSADHKIEKRKCTTESCLGVAKCVEDIGCTIEQNKCVSTVKCLEPYCSGNNCAFRSNCTDDIKPSSII
    ESGVEKFVCRTYSCDRTNGECIPNTLQSSSYCPKLSSKCEEYYCSAGTCMVQEKKCIKVSPYEENPCYEA
    TCDSETGNCVMNLVGCSSGMKVCGKVNGNCRCDASTSYQCKCDTSNGCTNGEVCDYTDGDPKCINVDNCE
    ELKGHDIVWEGCYKKVCKEYTANGTTQYVVDQEEYVCKEKVPEKCDGYANYVCSGNRECILVTTDKAIQE
    CKICDGNEIVNKCEGLTTSQGIPFVCKDGECQAPDEYDCKDLFKDRLSDCEQYYEWEYANGECKVIVKDG
    SKVILDSQCMYCSYDNILVDPAKLIKMDCTNKKNINGIPYVCRDGSCHIDDEFDCTKHENFPSKCLDVLD
    YKLIIGTTFDEYKCEWNSNEEKVKSLCKYCSGMDKESTLVDKCPNQVDASGNIYQMTCSDGDCKYEGDCN
    PTNNCFIQVKTGTSQLCEPTNVTICPSLPPSKPGEVICMKTNCDASGSIPKCSGVYDDSICSSNTADVGC
    ASLTGKCDTSTGYCIKKEFTKCSDEPSNDRDCTDKCYNYTCVETITEGVITHKWTSNIDGHEKALLYKNK
    CQDAYCDKETGEIETNFVQCDIDIQFPNMSKAAKNCFYCECSLQSESGWILTMYSDYADHRFSLDACGNC
    KINDELVDKDAVCLLWQDVDNTAAIAAGTTVAVVVAVIVVVMVIIAIGIKQTVDIVISARKNTVDNTVNN
    PQFTAKDDNATNANFNG
  • Molecule Role : Protective antigen
  • Molecule Role Annotation : Study tested if vaccination with the E. histolytica Gal/GalNAc lectin could prevent cecal infection in a C3H mouse model of amebic colitis. 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).
  • Related Vaccine(s): E. histolytica Gal/GalNAc lectin protein vaccine
3. GEh29
  • Gene Name : GEh29
  • Sequence Strain (Species/Organism) : Entamoeba histolytica
  • VO ID : VO_0011322
  • NCBI Nucleotide GI : 399673
  • NCBI Protein GI : 399674
  • Protein Accession : CAA50324.1
  • Other Database IDs : CDD:30799
    CDD:48564
    GOA:P19476
    InterPro: IPR000866
    InterPro: IPR012335
    InterPro: IPR012336
    UniProtKB/UniProt: P19476
  • Taxonomy ID : 5759
  • Gene Strand (Orientation) : ?
  • Protein Name : alkyl hydroperoxide reductase
  • Protein Length : 233
  • Protein Note : Peroxiredoxin [Posttranslational modification, protein turnover, chaperones]; COG0450
  • DNA Sequence : Show Sequence
    >gi|399673|emb|X70996.1| E.histolytica gEh29 gene for alkyl-hydroperoxidase reductase
    TTAGTTAAAAAGTATTTGATGACTTATTAGTTCATGTTACATATACAAAAATAATACTTTTATTGAAGTT
    TTGTGCCAATACATTTCTCTTTCTCCTCATCATATTCTTCATTAGATTCTTTGAGAATGTGTGGATGTGT
    GTATCTCCGTTTTCTTCTTTTTATCTAGTCATTTTTGTTTTCTATTTACCAGTTCTTTCATTATAAGTTG
    TTTAAATGTTGAATAATTACCATAATGAGAATAATGCAGAAGTGATGATGACGACATTTTTATTTTAGTT
    AAGTAAAGATGATTTTGGTAGTTCATTTGTCATTTAAACATCTCATCATCACCACAATCTCATCAATTCA
    ATCAGTCAAATGTCTTGCAATCAACAAAAAGAGTGTTGTAAAAAAGAATGTCAAGAGAAAGAATGTTGTA
    AAGAATGTTGTTGTCCAAGAATAAAAGCATTTAAGAAATTTATAAACACATTTGAAAAAGCACAAATTGG
    AAAAGAAGCACCAGAATTTAAAGCACCAGCATATTGTCCATGTGGTTCAATCAAAGAGATTGATATTAAT
    GAATATAGAGGAAAATATGTTGTATTGTTGTTTTATCCATTGGATTGGACATTTGTTTGTCCAACAGAAA
    TGATTGGATATAGTGAACTTGCAGGACAATTGAAAGAAATCAATTGTGAAGTTATTGGAGTGAGTGTAGA
    TTCAGTTTATTGTCATCAAGCATGGTGTGAAGCAGATAAAAGTAAAGGAGGAGTAGGAAAGTTGACATTC
    CCATTAGTATCAGATATTAAGAGATGCATTTCTATCAAATATGGAATGTTAAATGTCGAAGCAGGAATTG
    CAAGAAGAGGATATGTCATCATTGACGATAAAGGAAAAGTAAGATACATTCAAATGAATGATGATGGAAT
    TGGAAGATCAACGGAAGAAACAATCAGAATAGTGAAAGCAATTCAATTCAGTGATGAACATGGAGCAGTT
    TGTCCACTCAATTGGAAACCAGGCAAAGACACCATTGAACCAACACCAGATGGAATTAAGAAATATTTAA
    CAGCACATTAAAACAAACAAGATAATTTAATACAAATTATTTTATGTTTTATAAGAAGAAAATGATATAA
    TAAAAGATAAA
  • Protein Sequence : Show Sequence
    >gi|399674|emb|CAA50324.1| alkyl hydroperoxide reductase [Entamoeba histolytica]
    MSCNQQKECCKKECQEKECCKECCCPRIKAFKKFINTFEKAQIGKEAPEFKAPAYCPCGSIKEIDINEYR
    GKYVVLLFYPLDWTFVCPTEMIGYSELAGQLKEINCEVIGVSVDSVYCHQAWCEADKSKGGVGKLTFPLV
    SDIKRCISIKYGMLNVEAGIARRGYVIIDDKGKVRYIQMNDDGIGRSTEETIRIVKAIQFSDEHGAVCPL
    NWKPGKDTIEPTPDGIKKYLTAH
  • Molecule Role : Protective antigen
  • Molecule Role Annotation : 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).
  • Related Vaccine(s): E. histolytica Eh29 protein vaccine
4. SREHP
  • Gene Name : SREHP
  • Sequence Strain (Species/Organism) : Entamoeba histolytica HM-1:IMSS
  • VO ID : VO_0011324
  • NCBI Gene ID : 3402462
  • NCBI Protein GI : 67463194
  • Locus Tag : EHI_116360
  • Genbank Accession : DS571976
  • Protein Accession : XP_648254
  • Taxonomy ID : 294381
  • Gene Starting Position : 1107
  • Gene Ending Position : 1833
  • Gene Strand (Orientation) : -
  • Protein pI : 4.01
  • Protein Weight : 24419.56
  • Protein Length : 233
  • Protein Note : transcript EHI_116360A
  • DNA Sequence : Show Sequence
    >ref|NW_001915691.1|:1107-1833 Entamoeba histolytica HM-1:IMSS scf_1104750518053, whole genome shotgun sequence
    AGACTAAAGTCAAATAACTTCATTTAGAAGATGATAGCTATAATGATAGCACAGAAAACAATGAATGGAC
    TTGATGCAGCATCAAGGTTATTATTATCGTTATCTGAACTACTTCCTGATTTATCATTTGAATTACTAGT
    TGAGCTTGCTTCTGGTTTATTAGTTGAGCTTGCTTCTGGTTTATTAGTTGAGCTTGCTTCTGGTTTATTA
    GTTGAGCTTGCTTCTGGTTTATTAGTTGAGCTTGCTTCTGGTTTATTATCTGGTTTATCACTTGAGCTTG
    CTTCTGGTTTATTATCTGGTTTATCACTTGAGCTTGCTTCTGGTTTATTATCTGGTTTATCACTTGAACT
    TGCTTCTGGTTTATTATCTGGTTTATCACTTGAACTTGCTTCTGGTTTATTATCTGGTTTATCACTTGAA
    CTTGCTTCTGGTTTATCACTTGAACTTGCTTCTGGTTTATTATCTGGTTTATCACTTGAGCTTGATTCTG
    AGTTATCACTTGAACTTGCTTTTTCATCTTCATCATCTTCATTATCTTCATTTGAACTTGATTCTGGTTT
    TGCTGAGCTACTTTTTTCTTTTTCTTCAGCTTCTTCAAGCTTTTCAGGACTAGCTTCGTTCTTTAAAAAT
    ACACCGTAGATATTAGTATCTTTTACTTCTTGATCCAAATCAAGAATGATATTAGTTGCACTAGTGAATG
    CAATAAACAATAAAAATGCGAACATTG
  • Protein Sequence : Show Sequence
    >gi|67463194|ref|XP_648254.1| serine-rich protein [Entamoeba histolytica HM-1:IMSS]
    MFAFLLFIAFTSATNIILDLDQEVKDTNIYGVFLKNEASPEKLEEAEEKEKSSSAKPESSSNEDNEDDED
    EKASSSDNSESSSSDKPDNKPEASSSDKPEASSSDKPDNKPEASSSDKPDNKPEASSSDKPDNKPEASSS
    DKPDNKPEASSSDKPDNKPEASSTNKPEASSTNKPEASSTNKPEASSTNKPEASSTSNSNDKSGSSSDND
    NNNLDAASSPFIVFCAIIIAIIF
  • Molecule Role : Protective antigen
  • Molecule Role Annotation : Report describes a recombinant fusion protein containing the serine-rich Entamoeba histolytica protein (SREHP), a protective antigen derived from virulent amebae, and a bacterially derived maltose-binding protein (MBP) from an attenuated strain of Salmonella typhimurium. Gerbils vaccinated with S typhimurium SREHP-MBP were protected against amebic liver abscess after challenge with E. histolytica, the most common extraintestinal complication of amebiasis (Zhang and Stanley, 1996).
  • Related Vaccine(s): E. histolytica SREHP protein vaccine
III. Vaccine Information
1. E. histolytica CEL-170/4 protein vaccine
a. Vaccine Ontology ID:
VO_0011414
b. Type:
Subunit vaccine
c. Status:
Research
d. Antigen
E. histolytica alactose-specific adherence lectin heavy subunit (CEL-170/4)
e. Gene Engineering of CEL-170/4
  • Type: Recombinant protein preparation
  • Description: The galactose-specific lectin has been purified from a pathogenic strain of E. histolytica by monoclonal antibody affinity chromatography (Petri and Ravdin, 1991).
  • Detailed Gene Information: Click here.
f. Adjuvant: complete Freund's adjuvant
g. Adjuvant: incomplete Freund's adjuvant
h. Immunization Route
Intraperitoneal injection (i.p.)
i. Mongolian Gerbil Response
  • Vaccination Protocol: Adult male gerbils were immunized by intraperitoneal or subcutaneous injection of 10 ,ug of the affinity-purified lectin emulsified in complete Freund's adjuvant (GIBCO, Grand Island, N.Y.) and boosted with 10 ,ug of the lectin in incomplete Freund's adjuvant at 2 and 4 weeks. Control gerbils were sham immunized with Freund's complete and incomplete adjuvants alone. Prechallenge gerbil sera were collected at 5 weeks after the initial immunization by cardiac puncture (Petri and Ravdin, 1991).
  • Challenge Protocol: Gerbils were challenged intrahepatically with E. histolytica (Petri and Ravdin, 1991).
  • Efficacy: Researcherse tested the ability of the galactose-specific adherence lectin of E. histolytica to elicit a protective immune response in conjunction with Freund's incomplete and complete adjuvants. Four independent trials demonstrated complete protection from amebic liver abscess formation in 67% of lectin-immunized gerbils. The gerbil antilectin antibodies were shown by Western immunoblotting to be directed to the heavy subunit (CEL-170/4) but not the light subunit of the lectin (Petri and Ravdin, 1991).
2. E. histolytica Eh29 protein vaccine
a. Vaccine Ontology ID:
VO_0011450
b. Type:
Subunit vaccine
c. Status:
Research
d. Antigen
E. histolytica alkyl hydroperoxide reductase Eh29
e. Gene Engineering of GEh29
  • 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.
f. Adjuvant: incomplete Freund's adjuvant
g. Immunization Route
Intraperitoneal injection (i.p.)
h. 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).
3. E. histolytica Gal/GalNAc lectin protein vaccine
a. Vaccine Ontology ID:
VO_0011451
b. Type:
Subunit vaccine
c. Status:
Research
d. Antigen
E. histolyica Gal/GalNAc lectin
e. Gene Engineering of Gal/GalNAc lectin
  • 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.
f. Adjuvant: complete Freund's adjuvant
g. Adjuvant: incomplete Freund's adjuvant
h. Immunization Route
Intraperitoneal injection (i.p.)
i. 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).
4. E. histolytica SREHP protein vaccine
a. Vaccine Ontology ID:
VO_0011416
b. Type:
Subunit vaccine
c. Status:
Research
d. Antigen
E. histolytica serine-rich protein (SREHP)
e. Gene Engineering of SREHP
  • Type: Recombinant protein preparation
  • Description: Expressed the SREHP-MBP molecule in an attenuated vaccine strain of Salmonella typhimurium (Zhang and Stanley, 1996).
  • Detailed Gene Information: Click here.
f. Immunization Route
Oral
g. Gerbil Response
  • Vaccination Protocol: female BALB/c mice or gerbils were deprived of water and food for 4 h and then were given 50 ml of 10% sodium bicarbonate solution per orogastric gavage with a 21-gauge ball-tipped gavage needle. Five minutes later, they received by gavage 50 ml of 0.16Mphosphate-buffered saline (PBS), pH 7.0, containing 109 S. typhimurium cells harboring either pSS3137 (Stm-SREHP) or pYA3137 (Stm-Ctrl). Mice and gerbils were immunized on days 0, 7, and 21. Serum samples were obtained on days 0, 7, 21, and 28 (Zhang and Stanley, 1996).
  • Challenge Protocol: On day 35 (14 days following the final booster immunization) control gerbils vaccinated with Stm-Ctrl and gerbils vaccinated with Stm-SREHP were challenged intrahepatically with 5 x 105 E. histolytica HM1:IMSS trophozoites (Zhang and Stanley, 1996).
  • Efficacy: Report describes a recombinant fusion protein containing the serine-rich Entamoeba histolytica protein (SREHP), a protective antigen derived from virulent amebae, and a bacterially derived maltose-binding protein (MBP) from an attenuated strain of Salmonella typhimurium. Gerbils vaccinated with S typhimurium SREHP-MBP were protected against amebic liver abscess after challenge with E. histolytica, the most common extraintestinal complication of amebiasis (Zhang and Stanley, 1996).
IV. References
1. Carrero et al., 2010: Carrero JC, Contreras-Rojas A, Sánchez-Hernández B, Petrosyan P, Bobes RJ, Ortiz-Ortiz L, Laclette JP. Protection against murine intestinal amoebiasis induced by oral immunization with the 29kDa antigen of Entamoeba histolytica and cholera toxin. Experimental parasitology. 2010; ; . [PubMed: 20303954].
2. Houpt et al., 2004: Houpt E, Barroso L, Lockhart L, Wright R, Cramer C, Lyerly D, Petri WA. Prevention of intestinal amebiasis by vaccination with the Entamoeba histolytica Gal/GalNac lectin. Vaccine. 2004; 22(5-6); 611-617. [PubMed: 14741152].
3. Petri and Ravdin, 1991: Petri WA Jr, Ravdin JI. Protection of gerbils from amebic liver abscess by immunization with the galactose-specific adherence lectin of Entamoeba histolytica. Infection and immunity. 1991; 59(1); 97-9101. [PubMed: 1987067].
4. Wiki: Entamoeba histolytica: Entamoeba histolytica [http://en.wikipedia.org/wiki/Entamoeba_histolytica]
5. Zhang and Stanley, 1996: Zhang T, Stanley SL Jr. Oral immunization with an attenuated vaccine strain of Salmonella typhimurium expressing the serine-rich Entamoeba histolytica protein induces an antiamebic immune response and protects gerbils from amebic liver abscess. Infection and immunity. 1996; 64(5); 1526-1531. [PubMed: 8613356].