Molecular cloning of the 22–24 kDa excretory-secretory 22U protein of Dirofilaria immitis and other filarial nematode parasites

Frank, GlennR.; Wisnewski, Nancy; Brandt, K. S.; Carter, CliveR.D.; Jennings, NicolaS.; Selkirk, M.E.

doi:10.1016/s0166-6851(98)00173-x

Cited by 21 publications

(15 citation statements)

References 20 publications

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“…Electron microscopy locates Di‐P22U to the cuticle and hypodermis of adult D. immitis , but the protein is evidently obscured on the surface because no binding is detected by immunofluorescence assays on intact worms. Cloning of the B. malayi homologue reveals a 211‐amino acid protein with a typical signal peptide (49). This sequence matches a highly expressed vector‐derived L3 transcript in the B. malayi EST database which has been designated Bm‐nlt‐1 or novel larval transcript‐1 (50).…”

Section: Adult Surface‐associated Proteinsmentioning

confidence: 78%

“…In D.immitis , a secreted 22 kDa protein (Di‐P22U) has been isolated, antibodies to which react with a 24 kDa surface‐labelled protein from the L3 and L4 of B. malayi; the same antigen is also weakly represented on the adult parasite (49). Electron microscopy locates Di‐P22U to the cuticle and hypodermis of adult D. immitis , but the protein is evidently obscured on the surface because no binding is detected by immunofluorescence assays on intact worms.…”

Section: Adult Surface‐associated Proteinsmentioning

confidence: 99%

“…Although surface‐labelling data exist for Brugia infective larvae (36,83), the surface antigens from this stage have not been fully identified. Both cystatin proteins ( Bm ‐CPI‐1 and CPI‐2) can be iodinated by surface‐directed methods, and are secreted by L3 maintained in vitro , while Bm‐24 can also be identified in surface‐iodinated L3 preparations (49). A molecular approach to identify major L3 proteins by mRNA or EST abundance indicates which proteins may be required in quantity for invading parasites.…”

Section: Third Stage Larval Antigensmentioning

confidence: 99%

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Immunological genomics of Brugia malayi: filarial genes implicated in immune evasion and protective immunity

Maizels

Blaxter

Scott

2001

Parasite Immunology

100

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Filarial nematodes are metazoan parasites with genome sizes of> 100 million base pairs, probably encoding 15 000-20 000 genes. Within this considerable gene complement, it seems likely that filariae have evolved a spectrum of immune evasion products which underpin their ability to live for many years within the human host. Moreover, no suitable vaccine currently exists for human filarial diseases, and few markers have yet been established for diagnostic use. In this review, we bring together biochemical and immunological data on prominent filarial proteins with the exciting new information provided by the Filarial Genome Project's expressed sequence tag (EST) database. In this discussion, we focus on those genes with the highest immunological profile, such as inhibitors of host enzymes, cytokine homologues and stage-specific surface proteins, as well as products associated with the mosquito-borne infective larva which offer the best opportunity for an anti-filarial vaccine. These gene products provide a fascinating glimpse of the molecular repertoire which helminth parasites have evolved to manipulate and evade the mammalian immune response.

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Section: Adult Surface‐associated Proteinsmentioning

confidence: 78%

Section: Adult Surface‐associated Proteinsmentioning

confidence: 99%

Section: Third Stage Larval Antigensmentioning

confidence: 99%

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Immunological genomics of Brugia malayi: filarial genes implicated in immune evasion and protective immunity

Maizels

Blaxter

Scott

2001

Parasite Immunology

100

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“…Cloning and comparison with accumulating EST datasets revealed a multigene family with at least two members highly expressed in the L3; these two genes were named Abundant Larval Transcripts (alt)-1 and alt-2. Parallel studies have also identified alt-like genes in O. volvulus (241,242), L. sigmodontis (243), D. immitis (244), and A. viteae (245). All these members of the ALT family have a common protein structure that can be divided into a signal peptide, a variable and highly charged domain, and a conserved, cysteine-rich domain.…”

Section: The Abundant Larval Transcript Antigensmentioning

confidence: 96%

Helminth parasites – masters of regulation

Maizels

Balic

Gomez-Escobar

et al. 2004

Immunological Reviews

781

758

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Immune regulation by parasites is a global concept that includes suppression, diversion, and conversion of the host immune response to the benefit of the pathogen. While many microparasites escape immune attack by antigenic variation or sequestration in specialized niches, helminths appear to thrive in exposed extracellular locations, such as the lymphatics, bloodstream, or gastrointestinal tract. We review here the multiple layers of immunoregulation that have now been discovered in helminth infection and discuss both the cellular and the molecular interactions involved. Key events among the host cell population are dominance of the T-helper 2 cell (Th2) phenotype and the selective loss of effector activity, against a background of regulatory T cells, alternatively activated macrophages, and Th2-inducing dendritic cells. Increasingly, there is evidence of important effects on other innate cell types, particularly mast cells and eosinophils. The sum effect of these changes to host reactivity is to create an anti-inflammatory environment, which is most favorable to parasite survival. We hypothesize therefore that parasites have evolved specific molecular strategies to induce this conducive landscape, and we review the foremost candidate immunomodulators released by helminths, including cytokine homologs, protease inhibitors, and an intriguing set of novel products implicated in immune suppression.

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“…The sequences of L. sigmodontis genes found in this study were submitted to the EST database section of GenBank (accession numbers AW152683 to AW152860 and BE140074 to BE140093). (28); alt, abundant larval transcript (12,14); ant, abundant novel transcript; asp, ancylostoma secreted protein; col, collagen; cpi, cysteine protease inhibitor (12,18); cpl, cathepsin l; fba, fructose bisphosphate aldolase; mlc, myosin light chain; nlt, novel larval transcript (8); rpp, ribosomal phosphoprotein; spn, serpin (27); thi, thioredoxin; tin, troponin; tpx, thioredoxin peroxidase (10,17,22). b *, all ESTs from this cluster are from L3 stages.…”

mentioning

confidence: 99%

Analysis of Genes Expressed at the Infective Larval Stage Validates Utility of Litomosoides sigmodontis as a Murine Model for Filarial Vaccine Development

et al. 2000

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We used an expressed sequence tag approach to analyze genes expressed by the infective larvae of the rodent filarial parasite Litomosoides sigmodontis. One hundred fifty two new genes were identified, including several proposed as vaccine candidates in studies with human filarial parasites. Our findings have important implications for the use of L. sigmodontis as a model for filarial infection.The rodent filarial parasite Litomosoides sigmodontis has recently been proposed as an important model of filariasis because it is the only filarial species in which the full development cycle can take place in inbred laboratory mice (1, 19). The power of murine genetics and immunology can now be brought to bear on fundamental questions in filarial biology that have previously been intractable. Perhaps the most immediate application of this model is the rigorous testing of vaccine strategies. The main objective of a filarial vaccine would be to target the incoming vector-derived larvae without inducing an immune response to later stages that might damage the host. We and others have been studying genes that are specific to the third larval (L3) stage of human filarial parasites (12,13,27). This work has identified several possible vaccine targets, with the abundant larval transcript 1 (alt-1) gene emerging as a particularly promising candidate (11).The aim of this study was to sample genes expressed by the L3 stage of L. sigmodontis for comparison with gene expression in onchocerciasis and lymphatic filariasis parasites and thus to assess the utility of this rodent filaria as a model for vaccine studies. With this information, it will be possible to assess the validity of using the Litomosoides model to evaluate specific vaccine candidates. Further, the data will provide an important resource for comparative analysis of gene expression between species both within and outside the filariae.For this study, we used an L. sigmodontis L3 cDNA library (in UniZap XR; Stratagene, La Jolla, Calif.). Randomly chosen recombinants were picked and cDNA inserts (with an average size of ϳ640 bp) were PCR amplified using vector primers. Two hundred thirty PCR products were prepared using shrimp alkaline phosphatase and exonuclease I (Amersham Pharmacia Biotech Ltd., Uppsala, Sweden) (6) and sequenced using the 5Ј vector primer SAC (GGGAACAAAAG CTGGAG) and ABI Big DYE terminators (the Perkin-Elmer Corporation, Norwalk, Conn.). Sequencing reactions were analyzed using an ABI 377 automated sequencer. There were 197 successful sequences with an average read length of 421 bp. The clones are archived and are freely available to the research community.Sequences were edited to remove vector and poor 3Ј sequences and then compared to the public databases using the BLAST family of algorithms (2). Expressed sequence tags (ESTs) with no significant similarity to any protein sequences in the databases using a minimum BLASTX score of 80, with a probability of Ͻ1 ϫ e Ϫ8 , were designated as novel. Sequences were clustered using AssemblyLIGN (Oxford Molec...

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Molecular cloning of the 22–24 kDa excretory-secretory 22U protein of Dirofilaria immitis and other filarial nematode parasites

Cited by 21 publications

References 20 publications

Immunological genomics of Brugia malayi: filarial genes implicated in immune evasion and protective immunity

Immunological genomics of Brugia malayi: filarial genes implicated in immune evasion and protective immunity

Helminth parasites – masters of regulation

Analysis of Genes Expressed at the Infective Larval Stage Validates Utility of Litomosoides sigmodontis as a Murine Model for Filarial Vaccine Development

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