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J S Cordingley

Publications and source records attributed to J S Cordingley.

At least 19 recordsLinked to original sources

Differential antigen recognition by T cell populations from strains of mice developing polar forms of granulomatous inflammation in response to eggs of Schistosoma mansoni.

In humans, infection with schistosome helminths can lead to dissimilar forms of clinical disease. Likewise, in the experimental mouse system, identical infection protocols with Schistosoma mansoni cause a more severe granulomatous disease in the C3H strain than in the C57BL/6 strain. To address this difference, we developed panels of schistosomal egg antigen (SEA)-specific T cell hybridomas to compare the responses of C3H and C57BL/6 mice to the major egg antigen p40. All derived C3H T cell hybridomas, despite being clonally distinct and restricted by either I-Ak or I-Ek, responded to recombinant fragment 15-1 of the p40 antigen, while none of the C57BL/6 T cell hybridomas did. Consistent with the observed monoclonal T cell responses, polyclonal lymph node cells from schistosome-infected C3H mice reacted strongly to fragment 15-1, which contrasted sharply with the weak response displayed by the C57BL/6 strain. Moreover, studies with congenic mice demonstrated that the strong CD4+ T cell response to fragment 15-1 was under major histocompatibility complex control and segregated with the H-2k haplotype. These findings suggest that a dominant T cell response against a major egg antigen may represent a risk factor for the development of severe disease.

Animals

Osmolarity is an independent trigger of Acanthamoeba castellanii differentiation.

Like many yeasts, bacteria, and other sporulating microorganisms, Acanthamoeba castellanii (Neff), a free-living amoeba with pathogenic relatives, differentiates into a dormant form when deprived of nutrients. Acanthamoeba cysts redifferentiate into trophozoites when food is resupplied. We report here that Acanthamoeba encystment is also triggered by elevated osmolarity, and that osmolarity and cell surface receptor binding are synergistic in triggering differentiation. Additions of sodium chloride or glucose to rich growth media were used to produce specific osmolarity increases and similar encystment results were obtained with either additive. Although many organisms, including Acanthamoeba and mammalian cells, have been shown to adapt to hyperosmolar conditions, this is the first demonstration that hyperosmolarity can be a primary differentiation signal.

Acanthamoeba

Structure of synthetic peptide analogues of an eggshell protein of Schistosoma mansoni.

The peptide (Gly-L-Tyr-L-Asp-L-Lys-L-Tyr)6, referred to as F4-6, was synthesized as a model for a schistosome eggshell protein in which the Gly-Tyr-Asp-Lys-Tyr consensus sequence is repeated over 40 times. Analysis by CD, Fourier transform infrared spectroscopy, potentiometric and spectrophotomertric titrations, NMR, and molecular modeling suggests that F4-6 forms some type of left-handed structure. A likely possibility appears to be a left-handed alpha-helix stabilized by Lysi-Aspi +4 salt bridges and possibly Aspi-Tyri +4 hydrogen bonding and Tyr-Tyr interactions. Spectroscopic studies of a number of F4-6 analogues support this conclusion. For example, substitution of D-Ala for Gly produces a peptide with enhanced left-handed helical spectral characteristics, whereas an L-Ala substitution results in a peptide with minimal structure. These studies suggest that the F4 protein from Schistosoma mansoni may be the first example of a naturally occurring protein devoid of proline and carbohydrate that forms a left-handed helix composed of L-amino acids, although alternative forms of other left-handed structures have yet to be rigorously excluded.

Amino Acid Sequence

Schistosoma mansoni: genetic non-response to p40, the major protein antigen of the egg, reveals a novel mechanism enhancing IgM production during infection.

p40 is the major protein antigen in eggs and miracidia of Schistosoma mansoni. Immunization with recombinant p40 produced in bacteria and with p40 from miracidia reveals a conventional immune response gene effect in which H-2b mice fail to produce antibody against p40. This is true when either denatured recombinant p40 and non-denatured miracidial p40 are used as immunogens. In contrast, during infection all strains of mice produce antibodies to p40. However, non-responder H-2b mice produce only IgM to p40 and never any IgG. Thus, H-2b mice appear to be producing specific IgM to p40 in the absence of MHC-restricted T-cell help. The mechanism revealed in these non-responder mice might play an important role in stimulating the production of IgM 'blocking' antibodies to antigens from schistosomula which cross-react with egg antigens.

Animals

Detecting proteins containing 3,4-dihydroxyphenylalanine by silver staining of polyacrylamide gels.

Proteins in which some or all of the tyrosine side chains are post-translationally modified to dihydroxyphenylalanine have been found in several invertebrate phyla. In this paper we describe the unusual silver-staining properties of these 3,4-dihydroxyphenylalanine (Dopa)-proteins in silver-stained polyacrylamide gels. Our evidence suggests that the rapid silver staining of these proteins is due to the 3,4-dihydroxyphenol ring which is a highly effective reducing agent in the alkaline development conditions used in the final step of most silver-staining procedures. Normal proteins comprising the standard 20 amino acids and tyrosine on its own, do not reduce silver under these conditions. Pretreatment of the gels with acid-dichromate solutions abrogates the rapid staining of the Dopa-proteins. This rapid silver-staining technique will facilitate the rapid screening of many additional organisms for Dopa-proteins using sodium dodecyl sulfate gels and small amounts of tissue.

Animals

Schistosoma mansoni: eggshell formation is regulated by pH and calcium.

The protein precursors of the schistosome eggshell are synthesized and packaged into secretory vesicles in the vitelline cells. These vesicles appear to contain an emulsion of eggshell precursor material. Evidence is presented to show that these secretory vesicles are acidic as in other systems and that this acidity stabilizes the emulsion and prevents the eggshell cross-linking reactions from occurring. Alkalinizing treatments trigger eggshell formation within the secretory vesicles as shown by (1) the induction of autofluorescence and (2) by electron microscopy which shows that the eggshell precursors have aggregated within the secretory vesicles into spherical particles bearing microspines. These aggregates formed in the secretory vesicles were isolated and shown to have the same protease resistance and amino acid composition as authentic eggshell. The calcium ionophore A23187 induces scattered autofluorescence in intact female worms which electron micrographs show to be due to exocytosis of eggshell material. Based on these observations we propose a model for the formation of schistosome eggshell and suggest that it may apply to all trematodes in which the eggshell precursors are present as stable emulsions in the secretory vesicles of the vitelline cells.

Ammonium Chloride

The 86-kilodalton antigen from Schistosoma mansoni is a heat-shock protein homologous to yeast HSP-90.

We report the sequence of a cDNA clone encoding an 86-kDa polypeptide antigen (p86) from Schistosoma mansoni. Fusion proteins made in Escherichia coli are recognized by human infection sera. The reading frame of this antigen is highly homologous to those of the large heat-shock proteins of Saccharomyces cerevisiae (HSP90) and Drosophila melanogaster (HSP83). mRNA encoding p86 increases in response to heat shock of adult worms, as does HSP70. Comparisons of the sequences of HSP70 and HSP83 homologues show that these two families of heat-shock proteins are not significantly related except for the last four amino acid residues, which are Glu-Glu-Val-Asp in every case. This sequence is not found at the carboxy terminus of any other protein in the current databases.

Amino Acid Sequence

Possible eggshell protein gene from Schistosoma mansoni.

We have identified and sequenced a cDNA clone of a mRNA found only in mature female schistosomes. This mRNA is not detectably synthesized by female worms from single sex infections (unisexual females), by males or by the developing miracidia in the eggs. The clone hybridises to a highly abundant polyadenylated mRNA of approximately 1500 nucleotides. The nucleotide sequence of the clone predicts a polypeptide comprising two repetitive regions. A pentapeptide repeat with the consensus sequence Gly-Tyr-Asp-Lys-Tyr, and a region rich in histidine residues. Hybrid selected mRNA translated in vitro with [3H]tyrosine as labelled amino acid yields a polypeptide of 48 kDa (p48) that corresponds to the major [3H]tyrosine labelled translation product of female worm total mRNA. p48 does not label with [35S]methionine and is absent from the translation products of male and unisexual female mRNAs. The amino acid sequence of p48 has significant homologies to silk moth chorion proteins and we suggest that it is one of the major components of the schistosome eggshell probably accounting for the high level of [3H]tyrosine incorporation into the vitellaria of Schistosoma mansoni. The tyrosine content of the polypeptide suggests that it may play a role in phenol oxidase mediated cross-linking of the schistosome eggshell and in support of this we find that mushroom phenol oxidase will cause the specific cross-linking of p48 in in vitro translation products.

Animals

Sequence and expression of a major egg antigen from Schistosoma mansoni. Homologies to heat shock proteins and alpha-crystallins.

One of the major proteins of eggs and miracidia (p40) of Schistosoma mansoni has an apparent molecular weight of 40,000 and elicits a strong immune response in over 90% of patients. The antigen consists of a family of at least four near identical proteins, probably encoded by a multi-gene family, and expression of the p40 polypeptides is differentially regulated around the parasite's life cycle. We have isolated and sequenced cDNA clones encoding two variants of the antigen and expressed one p40 clone in Escherichia coli. The fusion protein elicits antibodies which immunoprecipitate p40 and recognise antigens of identical sizes in S. haematobium and S. bovis. The open reading frame encoding this antigen specifies a protein which shares a block of sequence homology with alpha-crystallins and Drosophila small heat shock proteins.

Amino Acid Sequence

Identification by message selection of cDNA clones encoding antigens of Schistosoma mansoni.

cDNA clone banks have been constructed in a plasmid vector (pJSC73) using mRNA isolated from adult worms and eggs of Schistosoma mansoni. These clone banks have been screened by message selection (hybrid release translation) and clones containing fragments of genes encoding schistosome antigens have been identified by immunoprecipitation of the corresponding mRNA in vitro translation product. Over 50 clones encoding schistosome antigens have been identified including those of the 100 000, 86 000, 28 000, and 27 000 molecular weight surface antigen precursors.

Animals

Primary structure of the gene encoding the bifunctional dihydrofolate reductase-thymidylate synthase of Leishmania major.

We have determined the nucleotide sequence of the dihydrofolate reductase-thymidylate synthetase (DHFR-TS) gene of the protozoan parasite Leishmania major (dihydrofolate reductase, EC 1.5.1.3 and thymidylate synthase, EC 2.1.1.45). The DHFR-TS protein is encoded by a single 1560-base-pair open reading frame within genomic DNA, in contrast to vertebrate DHFRs or mouse and phage T4 TSs, which contain intervening sequences. Comparisons of the DHFR-TS sequence with DHFR and TS sequences of other organisms indicate that the order of enzymatic activities within the bifunctional polypeptide chain is DHFR followed by TS, the Leishmania bifunctional DHFR-TS evolved independently and not through a phage T4-related intermediate, and the rate of evolution of both the DHFR and TS domains has not detectably changed despite the acquisition of new functional properties by the bifunctional enzyme. The Leishmania gene is 86% G+C in the third codon position, in contrast to genes of the parasite Plasmodium falciparum, which exhibit an opposite bias toward A+T. The DHFR-TS locus is encoded within a region of DNA amplified in methotrexate-resistant lines, as previously proposed.

Amino Acid Sequence

Genetic influence on the antibody response to antigens of Schistosoma mansoni in chronically infected mice.

Immunoprecipitations of in vitro translation products of mRNA from adult Schistosoma mansoni worms with sera from chronically infected mice of 12 inbred strains reveal a strain-dependent heterogeneity in the antibody responses to schistosome antigens. Of the strains tested the response to the 86K antigen was restricted to mice of haplotypes H-2d H-2k, and H-2a while the 14K antigen was only recognized by H-2k mice. Responses to other antigens revealed the influence of non-H-2 genes on the antibody response although no clear correlation was apparent between the antigens recognized and the non-H-2 genes of the strains. Both dominant and recessive responses towards individual antigens were seen in F1 animals. Some of these results support the cross tolerance model of Ir gene function.

Animals

Immunity after treatment of human schistosomiasis mansoni. II. Identification of resistant individuals, and analysis of their immune responses.

Intensities of re-infection were monitored at three-monthly intervals after treatment of Schistosoma mansoni infections in a group of 119 Kenyan schoolchildren, whose levels of water contact were also observed. 22 children showed high reinfection intensities (greater than 100 eggs per gram of faeces) by 12 months after treatment, and were considered to be susceptible. Out of 70 children who showed low reinfection intensities during the same period (less than 30 eggs per gram), 35 showed high levels both of total water contact and of contact with sites containing infected snails. In these children, the relative lack of reinfection could not be attributed to a lack of exposure, and they were classified as resistant to reinfection. Comparison of the two groups, resistant and susceptible, revealed no difference in pretreatment intensities of infection. However, there was a marked difference in age, the mean age of the resistant group being two years greater than that of the susceptible group, within a restricted starting age range. These findings indicated that resistance was an acquired and age-dependent phenomenon, not obviously related to previous egg-induced pathology. Studies of immune responses revealed no clearcut correlate of resistance, but there were interesting differences between the two groups. Whereas anti-egg antigen responses declined after treatment to a greater extent in the resistant than in the susceptible group, antibodies mediating eosinophil-dependent killing of schistosomula rose markedly in both groups, strongly suggesting that the resistant children were being exposed to cercariae. Anti-adult worm antibodies rose sharply in both groups immediately after treatment, and thereafter declined to pretreatment levels. Although some individual children showed high levels of IgE anti-schistosomulum antibodies, there were no significant differences between the two groups. Since all children showed detectable levels of antibodies mediating eosinophil-dependent killing of schistosomula, the possibility was considered that such antibodies might be a necessary, but not a limiting, factor in immunity. Instead, the functional state of the effector cells mediating antibody-dependent killing might be limiting. Eosinophil levels, measured as an indirect estimate of eosinophil functional activity, did not differ between the two groups. There were, however, marked differences between different individuals in their capacity to produce eosinophil-stimulating monocyte mediators, and although this cannot yet be related to resistance, this aspect is worth further study.(ABSTRACT TRUNCATED AT 400 WORDS)

Adolescent

Nucleotide sequence of the 5S ribosomal RNA gene repeat of Trypanosoma brucei.

The 750 base pair tandem repeat specifying the 5S ribosomal RNA of Trypanosoma brucei brucei has been cloned and four independent clones sequenced to completion. The repeat specifies only a single 5S rRNA and is unusually long when compared with other 5S gene repeats. The sequenced copies contain a number of sequence polymorphisms similar to those seen in the ribosomal genes of other organisms. By comparison with the consensus sequence for RNA polymerase III promoters ('internal control regions') a possible 'internal control region' for RNA polymerase III can be located in the predicted position within the 5S ribosomal RNA sequence.

Animals

Complete nucleotide sequence of an unusual mobile element from trypanosoma brucei.

The complete nucleotide sequence of a mobile element from Trypanosoma brucei is presented along with the sequence of its target site, which shows that the insertion has generated a 7 base pair direct repeat. The cloned copy of the element is a dimeric structure, one end of each monomer consisting of a stretch of 14 A residues preceded by a putative trypanosome polyadenylation signal. Six base pairs of DNA of unknown origin are found in the dimer between the two copies of the element. Evidence suggests that the element is present in the genome mainly as a monomer whose sequence is conserved across several species of trypanosome. The element contains an open reading frame encoding the same 160 amino acid protein in both sequenced copies and is extensively transcribed from both strands.

Animals

Immunoprecipitation of surface antigen precursors from Schistosoma mansoni messenger RNA in vitro translation products.

Messenger RNA has been isolated from adults and eggs of Schistosoma mansoni and translated in vitro in mRNA dependent rabbit reticulocyte lysate. The in vitro translation products have been immunoprecipitated using a wide variety of hyperimmune and infection sera from rabbits, mice and humans. A large number of in vitro translation products are precipitated by these sera, and we have identified a subset of the immunoprecipitated polypeptides which are expressed on the surface of the young schistosomulum. Messenger RNA from both adults and eggs directs the synthesis of these polypeptides suggesting that at least some of the surface proteins of the young schistosomulum are being synthesised throughout the life cycle. cDNA clone banks prepared from adult mRNA will therefore contain the genes for these schistosomulum surface antigens greatly facilitating their isolation.

Animals