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Bronchial provocation with Ascaris allergen evoked bronchoconstriction in home-bred Macaca arctoides monkeys sensitized by experimental infection with embryonated Ascaris suum ova. Inhalation of Ascaris allergen by aerosol prior to infection produced no changes in lung function. In infected animals total lung resistance (RL) increased and dynamic lung compliance (Cdyn) decreased following Ascaris inhalation. The changes in lung function reached a peak, 2-5 min after allergen inhalation, lasted for approximately 30 min and were associated with increases in arterial plasma histamine levels and decreases in arterial Po2 levels. Reproducible changes in lung function were obtained when the monkeys were challenged at bi-weekly intervals and lung sensitivity to Ascaris was maintained for at least 6 months. Histamine produced similar changes in RL and Cdyn before and after infection. Ascaris-induced bronchoconstriction was reversed by the beta 2-stimulant, salbutamol, and was partially reversed by cholinergic blockade with atropine. The responses were not inhibited by antihistamines or sodium cromoglycate although a new anti-allergic agent, FPL 58668 (disodium salt), inhibited Ascaris-induced bronchoconstriction and the increase in plasma histamine levels seen after Ascaris inhalation. Ascaris-induced bronchoconstriction in experimentally infected monkeys provides an animal model demonstrating many of the characteristics of allergic asthma in man and does not require the use of wild-caught monkeys.
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Ascaris trypsin inhibitors 1, 2, and 3 have arginine at their reactive P1 site. This corrects an earlier report that lysine is the reactive P1 site residue in Ascaris trypsin inhibitor 1 (Peanasky et al., 1974, Bayer Symposium V: Proteinase Inhibitors, pp. 649-666). The present work illustrates that the residue modification method of Fritz et al. (1969, Z. Physiol. Chem., 350, 933-944) may not be reliably interpreted when trypsin inhibitors have an unusually high lysine content (greater than 12% of the molecular weight of the inhibitor). Thus the following procedure is recommended: treat the inhibitor with maleic anhydride first and second with butanedione reagent; then remove the maleyl groups in an acid environment and determine the activity of the inhibitor. Immunoperoxidase staining shows that antibody to Ascaris trypsin inhibitor 1 binds to body wall muscle, intestine, eggs and sperm in cross-sections of Ascaris. Antibody to TLCK-porcine trypsin binds to the same tissues and at the same sites as the antibody to Ascaris trypsin inhibitor 1. This is the first demonstration that a protein that originated in the host has been found in the parasite, Ascaris. Analyses of homogenates and of extracts of separated tissues always show an excess of free trypsin inhibitor and no evidence of active trypsin. The host protein is present inside the parasite, probably as the trypsin-inhibitor complex.
In the previous study, we found an eosinophil chemotactic factor of the parasite (ECF-P) in extracts from the body cavity fluid of the Ascaris species. In this study, the physiochemical characteristics of ECF-P were determined in order to elucidate the relationship between ECF-P and Ascaris antigens. ECF-P was active in both in vivo and in vitro chemotactic assay systems and was found to be heat labile, nondialyzable, and stable to lyophilization. The estimated m.w. was approximately 30,000 daltons. The isoelectric point of ECF-P was 8.5. It was quite different from the Ascaris antigen in the same extract, or various Ascaris allergens that had been reported previously by other researchers. Furthermore, ECF-P did not show any activity in eliciting a guinea pig passive cutaneous anaphylaxis (PCA) reaction. From these experimental results, we concluded that ECF-P is not identical to Ascaris antigens. In addition, we found that the neutrophil chemotactic factor of the parasite (NCF-P), with at least two components, is present in the Ascaris extract, and is also heat labile and resistant to dialysis and lyophilization, but separable from coexistent ECF-P by reason of their different physiochemical properties.
Two subcellular fraction, P-1 and P-2, were isolated by differential centrifugation from 0.25 M sucrose muscle homogenates of the parasitic roundworm, Ascaris lumbricoides suum. Morphological studies indicated that P-1 fraction consisted of intact mitochondria, whereas P-2 fraction consisted almost exclusively of vesicular components. The difference spectrum of Ascaris microsomes showed a characteristic b-type cytochrome spectrum with three distinct absorption peaks at 560, 525, and 424 nm. However, the alpha-peak at 560 nm was asymmetric with a shoulder at 555 nm. This microsomal b-type cytochrome was reduced by NADH, which was inhibited by rotenone and HgCl2. The reduced b-type cytochrome was easily reoxidized by shaking. NADH-oxidase activity observed in Ascaris microsomes was inhibited by rotenone, but not by KCN, NaN3, and antimycin A. On the other hand, NADH-cytochrome c and NADH-neotetrazolium (NT) reductase activities in Ascaris microsomes were not inhibited by antimycin A and rotenone, but were inhibited by HgCl2. Further observations indicated that neither HgCl2 nor rotenone inhibited Ascaris microsomal NADH-ferricyanide (FC) reductase activity, but rabbit antibody prepared against the purified NADH-FC reductase inhibited the NADH-cytochrome c reductase activity, the reduction of b-type cytochrome and the NADH-oxidase activity, as well as microsomal NADH-FC reductase activity.
The protein profile of adult female Ascaris lumbricoides and Ascaris suum originating from humans and pigs, respectively, was studied using two-dimensional polyacrylamide gel electrophoresis. Six different major protein spots specific for A. lumbricoides were identified irrespective of their geographical origin and no major specific spot was encountered in A. suum. No major differences in the protein profiles between the extract by phosphate-buffered saline and urea were encountered for either Ascaris species. It is therefore possible to use 2D-PAGE as a tool for discriminating the closely related Ascaris species from humans and pigs.
The cosmopolitan nematode parasites Ascaris lumbricoides, Ascaris suum, and Toxocara canis are closely related phylogenetically, and are all pathogenic to man. In the case of the latter, the antigens released by the tissue-invasive parasitic larvae in vitro ('excretory/secretory' or 'ES' antigens) are routinely used for serodiagnostic purposes. Here we have found, using radioimmunoprecipitation with defined rabbit antiserum, and SDS-PAGE, that there is a significant antigenic similarity between the secreted and somatic antigens of the three nematodes, and have characterized cross-reactive components. Among these is a 14 kD internal protein which has a homologue in all three parasites. This molecule is the subject of an IgG antibody response in Ascaris infection, but there is no measurable response to it in toxocariasis. Lastly, using quantitative immunofluorescence, the antigens exposed on the surface of intact, living, larvae were found to be cross-reactive or specific depending on the developmental stage of the parasites. This means that the surface of tissue-invasive Ascaris larvae bears stage-specific epitopes.
Disposal of wastewater sludges in agricultural soil is a way to recover mineral and organic substances. Nevertheless disposing and handling such untreated, potentially contaminated sludges may be hazardous for human health and the environment. The aim of this study is to evaluate a method for sludge decontamination consisting in alkaline treatment with ammonia at different temperatures (22 degrees C, 30 degrees C, 40 degrees C) to establish its effects on the survival of Ascaris suum, Ascaris lumbricoides and Trichuris muris eggs. Our experiments show that the combination of alkalinization with NH4OH at a temperature of 30 degrees C causes the eggs to be inactivated. A 40 degrees C temperature was unfavourable to the development of these helminths in the eggs, with or without addition of NH4OH. At 22 degrees C ammonia did not have any effect on their viability. Ammonia at suitable temperatures therefore, is able to destroy Ascaris and Trichuris eggs. It is suggested that this technology be adopted to decontaminate wastewater sludge before using it as manure in agriculture.
We recently cloned a protective antigen that is commonly expressed in Ascaris species that infect humans and pigs. We evaluated the vaccinal effects of this 16-kilodalton protein (As16) in pigs, the natural host of Ascaris suum, by intranasal immunization. Pigs that received Escherichia coli-expressed recombinant As16 (rAs16) coupled with cholera toxin (CT) had significantly elevated levels of rAs16-specific serum immunoglobulin G (IgG) and mucosal-associated IgA antibodies. rAs16 evoked a type II immune response characterized by elevated levels of interleukin-4 and -10 in the culture supernatants of peripheral blood mononuclear cells of the vaccinated pigs. An increased level of rAs16-specific serum IgG1 was also detected. Pigs vaccinated with rAs16-CT were protected from migration of A. suum larvae through the lungs, as indicated by a 58% reduction in the recovery of lung-stage third-stage larvae (L3), compared with that in nonvaccinated controls. Purified immunoglobulin from rAs16-CT-vaccinated pigs inhibited survival of infective L3 and interrupted the molting of lung-stage L3. Immunofluorescence studies revealed that this immunoglobulin bound to the digestive tracts of L3, suggesting that it might inactivate functions of the gut tissues of Ascaris species. We conclude that rAs16 is a promising mucosal vaccine candidate for pig and human ascariasis.
Chromatographic analysis using Sephacryl S-300 was done on protein extract of adult Ascaris lumbricoides, A. vitulorum and Toxocara canis worms. Six fractions were separated from both Ascaris species and nine from T. canis. Fractions revealed a variety of molecular weights in relation to the three species of worms that ranged from 6,000-70,000 daltons. Crude extract of T. canis showed cross reaction with both species of Ascaris sera using double gel diffusion, while no reaction was obtained using a partially purified antigen.
A protein allergen of the parasitic nematode Ascaris has been purified to homogeneity by immunoaffinity chromatography. It is the most abundant protein species in the parasite's body fluid and has been named ABA-1. The allergen's molecular weight (MW) has been previously estimated at 14,000, but this sizing is currently under re-evaluation. The immunological activity of the protein was intact after purification, as attested by immunoprecipitation and passive cutaneous anaphylaxis. The IgE response to ABA-1 was under major histocompatibility complex (MHC) restriction in the rat, in which only RT1u strains were found to respond following infection with the parasite. The tissue-invasive and intestinal stages of both Ascaris lumbricoides (of humans) and Ascaris suum (of pigs) have an antigen of similar MW to ABA-1 in their secretions or among their somatic antigens. These are antigenically indistinguishable; they were found to have similar amino acid compositions, and their N-terminal amino acid sequences were identical to 41 residues. Finally, the apparent MW, amino acid composition and isoelectric point of ABA-1 all argue for close similarity to the previously described Allergen A of the parasite.
The materials released in vitro by the tissue-parasitic larval stages of the large roundworm of man, Ascaris lumbricoides, were analysed by radio-iodination, immunoprecipitation, and SDS-PAGE. The antigens were found to be heterogeneous, ranging in molecular weight from 14 to 410 kD, and were found to alter radically during the parasites' migration to the lungs. The antigens secreted by the infective and lung-stage larvae of the pig homologue, Ascaris suum, were compared with those of the human worms. This revealed a remarkable degree of homology between the products of the two, at both the molecular and immunological levels. The two species could be discriminated, however, on the basis of the SDS-PAGE profiles of the antigens secreted by both developmental stages of the parasites examined. Finally, antiserum to the canine ascarid infective to man, Toxocara canis, was found to precipitate a significant proportion of Ascaris-secreted molecules. These studies, therefore, confirm the potent antigenicity of excretory/secretory materials, and their potential for use in immunodiagnosis, but predict serious difficulties for seroepidemiology and the specific detection of ascariasis in man.
In continuation of studies of four rhesus monkeys infected with Ascaris suum (J Lab Clin Med 101:864-872, 1983), we report the duration of IgE-mediated skin reactivity and airway responses to Ascaris antigen from 15 weeks to longer than 2.8 years. A second group of four rhesus monkeys was infected with A. suum ova after determination of the threshold of airway reactivity to carbachol. Evaluation of these animals confirmed the initial results of the first group of animals studied in relation to induction of skin and airway reactivity to Ascaris antigen. In addition, all animals developed increased airway reactivity, demonstrated by increased reactivity to lower concentrations of carbachol. We report this as a demonstration of induced IgE-mediated antigen airway responsiveness accompanied by induction of increased airway reactivity in a primate model. The increased airway reactivity does not appear related to the induction of IgE antibody.
There has been continued controversy on the taxonomy of Ascaris lumbricoides Linnaeus, 1758 from humans and Ascaris suum Goeze, 1782 from pigs. This article reviews a range of comparative studies related to host susceptibility, morphology, karyotype, immunology and biochemistry, as well as molecular genetics in recent years.
The in vitro-released 'excretory/secretory' (ES) and somatic antigens of the third stage (infective) larva of Anisakis simplex were characterised by radioiodination, immunoprecipitation, and sodium dodecyl sulphate-polyacrylamide gel electrophoresis. Oral infection with the parasite elicited a substantial IgG antibody response to ES in infected rabbits and humans, with a minimal response to somatic materials. Serial serum sampling in experimental infection showed that there was a sequential recognition of distinct ES components. In contrast to oral infection, intraperitoneal exposure of rats with living parasites induced a strong response to both ES and somatic antigen preparations. Sequential recognition of ES antigens, and differential responses to somatic components, might, therefore, have application in the estimation of the age and degree of penetration by the nematodes in human infection. Extensive antigenic relationships were found between A. simplex and three other species of ascaridoid nematodes, namely Ascaris lumbricoides, Ascaris suum, and Toxocara canis, but none with a panel of non-ascaridoid nematodes. Evidence is presented that a Mr 14,000 component of A. simplex has a homologue in all of the ascaridoids examined, but does not elicit an antibody response in anisakiasis. Finally, the ES of A. simplex is shown to contain two proteinase activities, of approximately Mr 23,400 and 46,100, as revealed by separation on gelatin substrate gels, although the antigenicity of the enzymes remains to be established.