The gene coding for the major sheath protein of Litomosoides carinii microfilariae, gp22, is transcribed in oocytes and embryonic cells

Conraths, Franz J.; Schützle, B.; Schares, Gereon; Christ, Heike; Hobom, Gerd; Zahner, Horst

doi:10.1016/0166-6851(93)90034-u

Cited by 6 publications

(5 citation statements)

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“…In any case, our results support the concept of a dichotomy of the microfilarial sheath into a uterine-derived particulate layer and a basal layer produced by the developed embryo (Rogers, Ellis & Denham, 1976;Schraermeyer et al 1987), and provide further clues as to the nature of the constituents of these layers. Since gp22, a product of the embryo (Conraths et al 1993), is not accessible to antibodies directed against the outer surface of the sheath, it must be concluded that this molecule is part of the basal layer. In contrast, the 40/120 kDa antigens fulfil the requirements for potential constituents of the paniculate layer, i.e.…”

Section: Discussionmentioning

confidence: 99%

“…Parasite sections were prepared and processed as described elsewhere (Conraths et al 1993). In brief, live adult female parasites were fixed in Bouin's solution, cut into 8 segments defined according to the anatomy of the worm (Franz & Andrews, 1986) and embedded in paraffin.…”

Section: Immunohistochemistrymentioning

confidence: 99%

“…Parasite antigens were separated in 12-5% SDSpolyacrylamide gels under reducing conditions, transferred to PVDF membranes (Immobilon P, Millipore Inc., Eschborn, Germany) and probed with antibodies as described (Conraths et al 1993).…”

Section: Immunoblottingmentioning

confidence: 99%

“…It shows significant homology to a sheath protein of Brugia pahangi microfilariae (Mf22; Selkirk et al 1991). The transcription of the gp22 gene is developmentally regulated and occurs only in oocytes and early embryos (Conraths et al 1993). The results of Bardehle et al (1992) suggest that gp22 is highly cross-linked by disulphide bonds and may represent a part of the sheath matrix.…”

Section: Introductionmentioning

confidence: 99%

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Surface antigens ofLitomosoides cariniimicrofilariae: agglutinating antibodies react with sheath components of 40 and 120 kiloDalton molecular mass

et al. 1994

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This study was conducted to identify surface antigens of the microfilarial sheath of Litomosoides carinii which are accessible to antibodies. Rabbit antisera were raised against the soluble and insoluble fractions of purified sheaths by extracting them with a buffer containing 2-mercaptoethanol and sodium dodecylsulphate. These sera and rabbit hyperimmune sera directed against homogenates of total microfilariae, mature (i.e. microfilariae liberating) female parasites and excretory-secretory products of adult females were able to agglutinate live and formaldehyde-fixed microfilariae. When the antisera directed against sheath constituents were administered to patently infected Mastomys coucha, the microfilaraemia of these animals was rapidly reduced and remained low for a period of 2-3 weeks. Antibodies specifically binding to the microfilarial surface were immunoaffinity-purified on formaldehyde-fixed microfilariae. The antibodies react with sheath antigens of 40 and 120 kDa molecular mass which are produced by the epithelium of the distal uterus of the mature female, secreted and attached to the surface of the sheaths. A 120 kDa antigen recognized by anti-sheath surface antibodies was also detected in the excretory-secretory products of in vitro-cultured immature female L. carinii from day 30 post-infection onwards. In the excretory-secretory products of mature adult female parasites recovered on day 130 post-infection, this 120 kDa molecule was absent. However, material reacting with the antibody was detected in the stacking gel of SDS-polyacrylamide gels. This finding may indicate that the basic units forming the 120 kDa antigen of immature adults or microfilarial sheath surface antigens occur in a highly polymerized form in the excretory-secretory products of mature female parasites.

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Section: Discussionmentioning

confidence: 99%

Section: Immunohistochemistrymentioning

confidence: 99%

Section: Immunoblottingmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Surface antigens ofLitomosoides cariniimicrofilariae: agglutinating antibodies react with sheath components of 40 and 120 kiloDalton molecular mass

et al. 1994

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“…6B). As a control we amplified shp1 cDNA, which was previously shown to be detectable in developmental stages from oocytes to coiled embryos but not in mature stretched microfilariae (22).…”

Section: Shp3a and Shp3 Are Transcribed And Expressed In A Regionallymentioning

confidence: 99%

Cloning and Expression Analysis of Two Mucin-like Genes Encoding Microfilarial Sheath Surface Proteins of the Parasitic Nematodes Brugia and Litomosoides

Hirzmann¹,

Hintz²,

Kasper³

et al. 2002

Journal of Biological Chemistry

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In several filarial genera the first stage larvae (microfilariae) are enclosed by an eggshell-derived sheath that provides a major interface between the parasite and the host immune system. Analysis of the polypeptide constituents of the microfilarial sheath from the cotton rat filaria Litomosoides sigmodontis identified two abundant surface glycoproteins: Shp3a and Shp3. The corresponding genes and the orthologues of the human parasite Brugia malayi and the rodent filaria Brugia pahangi were cloned and sequenced. They encode secreted, mucin-like proteins with N-terminal Ser/Thrrich repeats and a C-terminal anchor domain rich in aromatic amino acids. About 75% of the protein molecular masses result from post-translational modifications. The Ser/Thr-rich motifs are supposed to serve as targets for dimethylaminoethanol-phosphate substitutions. These modifications were detected only on the sheaths of the late developmental stage of stretched microfilariae, corresponding with the expression of the proteins in the epithelium of the distal part of the uterus and the specific transcription of shp3 and shp3a in the anterior female worm segment. Genomic analysis of all three species demonstrated a conserved linkage of the two genes. Their transcripts undergo cis-and transsplicing. The transcription start sites of the primary transcripts were determined for the L. sigmodontis genes. The core promoter regions are remarkably conserved between the paralogue genes Ls-shp3a and Lsshp3 and their orthologues in Brugia, implicating conserved regulatory elements.The parasitic nematodes Brugia malayi, Brugia timori, and Wuchereria bancrofti are the causative agents of human lymphatic filariasis, a disease that afflicts an estimated 128 million people throughout the tropics (1) and in its final form results in severe obstructive alterations (elephantiasis). The adult lymphatic-dwelling parasites survive for years, and the viviparous females release large amounts of first stage larvae, microfilariae, into the blood stream. Completion of the filarial life cycle involves the uptake of the microfilariae by mosquitos, development to third stage larvae and transmission back to the vertebrate host. The microfilariae are completely surrounded by a bag-like, antibody-impermeable structure, the microfilarial sheath, which derives from the embryonic eggshell but is altered by maternal components secreted by the uterus epithelium (2). Parasitaemic hosts develop a parasite stage-specific immunological tolerance and fail to mount an antibody response to the microfilarial sheath surface proteins (3, 4). Therefore, it is of considerable interest to identify and characterize sheath surface components. The cotton rat filaria Litomosoides sigmodontis represents a suitable model organism for the lymphatics dwelling filarial parasites because of, in principle, a corresponding structure and genesis of the sheath (5). Previous studies with this parasite had identified two sheath proteins: Ls-Shp3a and Ls-Shp3 (40 and 120 kDa on SDS-PAGE) that appeared to ...

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Expression of the Microfilarial Sheath Protein 2 (shp2) of the Filarial ParasitesLitomosoides sigmodontisandBrugia malayi

Conraths

Hirzmann

Hobom

et al. 1997

Experimental Parasitology

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The gene coding for the major sheath protein of Litomosoides carinii microfilariae, gp22, is transcribed in oocytes and embryonic cells

Cited by 6 publications

References 14 publications

Surface antigens ofLitomosoides cariniimicrofilariae: agglutinating antibodies react with sheath components of 40 and 120 kiloDalton molecular mass

Surface antigens ofLitomosoides cariniimicrofilariae: agglutinating antibodies react with sheath components of 40 and 120 kiloDalton molecular mass

Cloning and Expression Analysis of Two Mucin-like Genes Encoding Microfilarial Sheath Surface Proteins of the Parasitic Nematodes Brugia and Litomosoides

Expression of the Microfilarial Sheath Protein 2 (shp2) of the Filarial ParasitesLitomosoides sigmodontisandBrugia malayi

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