RESUMEN

In 1937, Travassos described a new species of nematode in the genus Longistriata Schulz, 1926. He referred to it seven times as L. zetta in the main text, but also five times as L. zeta in the figure legends. This nominal species is currently assigned to the genus Guerrerostrongylus Sutton and Durette-Desset, 1991. The complete bibliography referring to this species from 1937 to date comprises only 22 works. Although the spelling 'zetta' has prevailed since 2011, the correct original spelling of its specific name remains unsettled. Acting as First Revisers under Articles 24.2.3 and 32.2.1 of the International Code of Zoological Nomenclature, we hereby choose 'zeta' as the correct original spelling of the specific name of this nematode, thus rendering 'zetta' an unavailable incorrect spelling. In making this choice, we have taken into account Travassos' obvious intention to name the species after the sixth letter of the Greek alphabet and the longer use of the spelling 'zeta' in the relevant literature, especially in those works in which 'zeta' (never 'zetta') was first combined with other generic names. We believe that standardizing the use of the spelling 'zeta' as the correct original spelling is the best way to stabilize this name.

Asunto(s)

Terminología como Asunto , Animales , Roedores/parasitología , América del Sur , Especificidad de la Especie , Heligmosomatoidea/clasificación , Heligmosomatoidea/anatomía & histología

RESUMEN

Nematode spicules vary in shape and size even between closely related species and, therefore, constitute key characters in nematode taxonomy for distinguishing between species. Spicules are seldom measured on fresh specimens, but rather at some time after extraction from culled hosts and after a period of preservation of the worms in chemical fixatives or by freezing. We carried out two experiments to assess the effects of freezing in Hanks' balanced salt solution, 70% or 80% ethanol and 10% formalin (both of the latter at room temperature and after storage at -80°C) on spicule length of Heligmosomoides bakeri at two time intervals after extraction from mice (Experiment 1, one and four weeks; Experiment 2, one and four months). In Experiment 1, no significant differences were detected, although there was some variation between treatments and over time. In Experiment 2, spicule length varied significantly between treatments and over time, the greatest shrinkage being in 80% ethanol and the least in 10% formalin. However, overall variation in spicule length was very limited, accounting for no more than 5.03% change in length over time and 4.95% between treatments at any of the periods of assessment. Therefore, while whole nematodes can shrivel and shrink in preservatives, making many measurements unreliable, our data indicated that spicule lengths are very little changed by preservation techniques over time, and so spicule length remains as a reliable taxonomic character.

Asunto(s)

Heligmosomatoidea , Nematodos , Trichostrongyloidea , Animales , Ratones

RESUMEN

Allintoshius Chitwood, 1937 is the only genus of the family Ornithostrongylidae (Travassos, 1937) Durette-Desset and Chabaud, 1981 that parasitizes bats. Currently, there are 10 valid species in the genus, of which 3 were described from Brazil. This study describes a new species of Allintoshius and records the first occurrence of a nematode of this genus parasitizing Artibeus lituratus (Olfers). Allintoshius gomesae n. sp. is characterized by having anterior region coiled, cephalic vesicle with cuticular dilation striated transversely, and claviform esophagus. Synlophe in females consists of 16 cuticular ridges at the mid-body. Males have large caudal bursa, and conic and small spicules, and the gubernaculum is absent. Females have uterus didelphic, amphidelphic, tail tip tapered, and ovijector divided into 2 divergent branches, subequal in length. The new species differs from its congeners especially by the shape of the tail tip, vulvar opening, and size of spicules. Allintoshius gomesae is the fourth species of Allintoshius from Brazil and the first report in Ar. lituratus, increasing the number of species recognized of the genus.

Asunto(s)

Quirópteros/parasitología , Heligmosomatoidea/clasificación , Infecciones por Strongylida/veterinaria , Animales , Brasil , Quirópteros/clasificación , Femenino , Heligmosomatoidea/anatomía & histología , Heligmosomatoidea/aislamiento & purificación , Intestino Delgado/parasitología , Masculino , Infecciones por Strongylida/parasitología

RESUMEN

CD4+ effector lymphocytes (Teff) are traditionally classified by the cytokines they produce. To determine the states that Teff cells actually adopt in frontline tissues in vivo, we applied single-cell transcriptome and chromatin analyses to colonic Teff cells in germ-free or conventional mice or in mice after challenge with a range of phenotypically biasing microbes. Unexpected subsets were marked by the expression of the interferon (IFN) signature or myeloid-specific transcripts, but transcriptome or chromatin structure could not resolve discrete clusters fitting classic helper T cell (TH) subsets. At baseline or at different times of infection, transcripts encoding cytokines or proteins commonly used as TH markers were distributed in a polarized continuum, which was functionally validated. Clones derived from single progenitors gave rise to both IFN-γ- and interleukin (IL)-17-producing cells. Most of the transcriptional variance was tied to the infecting agent, independent of the cytokines produced, and chromatin variance primarily reflected activities of activator protein (AP)-1 and IFN-regulatory factor (IRF) transcription factor (TF) families, not the canonical subset master regulators T-bet, GATA3 or RORγ.

Asunto(s)

Bacterias/patogenicidad , Infecciones Bacterianas/microbiología , Linfocitos T CD4-Positivos/microbiología , Linfocitos T CD4-Positivos/parasitología , Colon/microbiología , Colon/parasitología , Microbioma Gastrointestinal , Heligmosomatoidea/patogenicidad , Parasitosis Intestinales/parasitología , Animales , Bacterias/inmunología , Infecciones Bacterianas/genética , Infecciones Bacterianas/inmunología , Infecciones Bacterianas/metabolismo , Linfocitos T CD4-Positivos/inmunología , Linfocitos T CD4-Positivos/metabolismo , Cromatina/genética , Cromatina/metabolismo , Citrobacter rodentium/inmunología , Citrobacter rodentium/patogenicidad , Colon/inmunología , Colon/metabolismo , Citocinas/genética , Citocinas/metabolismo , Modelos Animales de Enfermedad , Perfilación de la Expresión Génica , Heligmosomatoidea/inmunología , Interacciones Huésped-Patógeno , Factores Reguladores del Interferón/genética , Factores Reguladores del Interferón/metabolismo , Parasitosis Intestinales/genética , Parasitosis Intestinales/inmunología , Parasitosis Intestinales/metabolismo , Masculino , Ratones Endogámicos C57BL , Ratones Transgénicos , Nematospiroides dubius/inmunología , Nematospiroides dubius/patogenicidad , Nippostrongylus/inmunología , Nippostrongylus/patogenicidad , Fenotipo , Salmonella enterica/inmunología , Salmonella enterica/patogenicidad , Análisis de la Célula Individual , Factor de Transcripción AP-1/genética , Factor de Transcripción AP-1/metabolismo , Transcriptoma

RESUMEN

Helminths regulate host immune responses to ensure their own long-term survival. Numerous studies have demonstrated that these helminth-induced regulatory mechanisms can also limit host inflammatory responses in several disease models. We used the Heligmosomoides bakeri (Hb) infection model (also known as H. polygyrus or H. polygyrus bakeri in the literature) to test whether such immune regulation affects skin inflammatory responses induced by the model contact sensitiser dibutyl phthalate fluorescein isothiocynate (DBP-FITC). Skin lysates from DBP-FITC-sensitized, Hb-infected mice produced less neutrophil specific chemokines and had significantly reduced levels of skin thickening and cellular inflammatory responses in tissue and draining lymph nodes (LNs) compared to uninfected mice. Hb-induced suppression did not appear to be mediated by regulatory T cells, nor was it due to impaired dendritic cell (DC) activity. Mice cleared of infection remained unresponsive to DBP-FITC sensitization indicating that suppression was not via the secretion of Hb-derived short-lived regulatory molecules, although long-term effects on cells cannot be ruled out. Importantly, similar helminth-induced suppression of inflammation was also seen in the draining LN after intradermal injection of the ubiquitous allergen house dust mite (HDM). These findings demonstrate that Hb infection attenuates skin inflammatory responses by suppressing chemokine production and recruitment of innate cells. These findings further contribute to the growing body of evidence that helminth infection can modulate inflammatory and allergic responses via a number of mechanisms with potential to be exploited in therapeutic and preventative strategies in the future.

Asunto(s)

Dermatitis por Contacto/inmunología , Tracto Gastrointestinal/parasitología , Heligmosomatoidea/inmunología , Inflamación/parasitología , Infecciones por Strongylida/inmunología , Animales , Quimiocinas/inmunología , Células Dendríticas/inmunología , Dermatitis por Contacto/parasitología , Dermatitis por Contacto/prevención & control , Modelos Animales de Enfermedad , Femenino , Inflamación/prevención & control , Ratones , Ratones Endogámicos C57BL , Piel/inmunología , Piel/parasitología , Piel/patología

RESUMEN

Parasite life history can be affected by conditions of the host and of the external environment. Rapamycin, a known immunosuppressant of mammals, was fed to laboratory mice that were then infected with the Trichostrongylid nematode Heligmosomoides bakeri to determine if host rapamycin exposure would affect parasite survival, growth, and reproduction. In addition, adult worms from control fed mice were directly exposed to rapamycin to assess if rapamycin would affect worm viability and ex vivo reproduction. We found that host ingestion of rapamycin did not affect H. bakeri survival or growth for male or female worms, but female worms had increased reproduction both in vivo and when removed from the host and cultured ex vivo. After direct rapamycin exposure, motility of female worms was greater at low levels of rapamycin compared to high levels of rapamycin or high levels of DMSO (the vehicle used to solubilize rapamycin) in control media, but was similar to females in low levels of DMSO in control media. Male motility was not affected by the presence of rapamycin or DMSO in the media. Ex vivo egg deposition was higher when exposed to rapamycin than when cultured in control media that contained DMSO, regardless of DMSO dose. Overall, we conclude that host ingestion of rapamycin or direct exposure to rapamycin was generally favorable or neutral for parasite life history traits.

Asunto(s)

Heligmosomatoidea/efectos de los fármacos , Inmunosupresores/farmacología , Sirolimus/farmacología , Análisis de Varianza , Animales , Dimetilsulfóxido/administración & dosificación , Dimetilsulfóxido/farmacología , Femenino , Heligmosomatoidea/crecimiento & desarrollo , Heligmosomatoidea/fisiología , Inmunosupresores/uso terapéutico , Intestino Delgado/parasitología , Masculino , Ratones , Ratones Endogámicos C57BL , Movimiento/efectos de los fármacos , Oviposición/efectos de los fármacos , Reproducción/efectos de los fármacos , Factores Sexuales , Razón de Masculinidad , Sirolimus/uso terapéutico

RESUMEN

Extracellular RNA has been proposed to mediate communication between cells and organisms however relatively little is understood regarding how specific sequences are selected for export. Here, we describe a specific Argonaute protein (exWAGO) that is secreted in extracellular vesicles (EVs) released by the gastrointestinal nematode Heligmosomoides bakeri, at multiple copies per EV. Phylogenetic and gene expression analyses demonstrate exWAGO orthologues are highly conserved and abundantly expressed in related parasites but highly diverged in free-living genus Caenorhabditis. We show that the most abundant small RNAs released from the nematode parasite are not microRNAs as previously thought, but rather secondary small interfering RNAs (siRNAs) that are produced by RNA-dependent RNA Polymerases. The siRNAs that are released in EVs have distinct evolutionary properties compared to those resident in free-living or parasitic nematodes. Immunoprecipitation of exWAGO demonstrates that it specifically associates with siRNAs from transposons and newly evolved repetitive elements that are packaged in EVs and released into the host environment. Together this work demonstrates molecular and evolutionary selectivity in the small RNA sequences that are released in EVs into the host environment and identifies a novel Argonaute protein as the mediator of this.

Asunto(s)

Proteínas Argonautas/genética , Evolución Molecular , Heligmosomatoidea/genética , ARN Interferente Pequeño/genética , Animales , Caenorhabditis elegans/genética , Heligmosomatoidea/patogenicidad , Humanos , Filogenia

RESUMEN

Coiling patterns of heligmonellid nematodes were examined for 520, 208, and 33 individuals of Nippostrongylus brasiliensis, Orientostrongylus tenorai, and Sabanema sp., respectively, collected from murine rodents of Indonesia. Besides typical sinistral coiling, complete dextral coiling was found in 3.3% of N. brasiliensis and 12.1% of Sabanema sp. Mixed coiling with partial sinistral and dextral patterns was also observed in 38.8% of N. brasiliensis, 60.7% of Sabanema sp., and 3.4% of O. tenorai. In dextral coils, the left ventral area with large ridges was located inside as in sinistral coils, keeping the ability to cling to intestinal villi. The cuticular dilatation at left to left dorsal area was located caudally in sinistral coils but rostrally in dextral coils. Presence of mixed coiling indicates that the coiling patterns can change. As the transition of coiling pattern accompanies a change in direction of coil axis, it is surmised that the dextral coiling may be chosen when a worm leaves a villus to move to another villus.

Asunto(s)

Heligmosomatoidea/fisiología , Intestinos/parasitología , Microvellosidades/parasitología , Murinae/parasitología , Enfermedades de los Roedores/parasitología , Animales , Femenino , Heligmosomatoidea/ultraestructura , Indonesia , Intestinos/ultraestructura , Masculino , Microvellosidades/ultraestructura , Nippostrongylus/fisiología , Nippostrongylus/ultraestructura , Ratas/parasitología

RESUMEN

Avena sativa L., 1753 (Poaceae) is used as feed for livestock and as a crop rotation agent. The purpose of the study was to examine the molecular mechanisms behind the antihelminth activity of the oat saponins avenacoside B (AveB) and 26-desglucoavenacoside B (26DGAveB) by evaluating their effect on Heligmosomoides bakeri, a parasitic nematode of mice. The avenacosides AveB and 26DGAveB were separated and purified from A. sativa green leaves, and their mycotoxic activity was confirmed against the fungus Trichoderma harzianum. The anti-nematode activity of the avenacosides was measured by egg hatching assay. In the surviving L3 larvae exposed to avenacosides, the expression of CED-9, a protein of the apoptosis pathway, was identified by Western blotting. The protein profile of L3 larvae was monitored by High Performance Liquid Chromatography (HPLC). The action of saponins on glycoprotein pump (Pgp) activity in L3 larvae was compared to that of the pump blocker Verapamil (VPL). A mouse model was used to measure the infectivity of L3 larvae exposed to AveB and 26DGAveB, and the outcome of the immune response. Both compounds induced morphological changes in larvae and blocked Pgp activity; however, only 26DGAveB provoked expression of CED-9. The infected mice displayed changes in the molecular pattern of larval proteins and enhanced IL-4 production, indicating that avenacosides reduced the infectivity of H. bakeri larvae. In avenacosides, the residue without glucose at the C26 position demonstrated greater anti-nematode activity. Our findings indicate that A. sativa compounds are natural products with anti-parasitic activity.

Asunto(s)

Antihelmínticos/farmacología , Heligmosomatoidea/efectos de los fármacos , Saponinas/farmacología , Infecciones por Strongylida/tratamiento farmacológico , Miembro 1 de la Subfamilia B de Casetes de Unión a ATP/metabolismo , Animales , Antihelmínticos/química , Avena/química , Caenorhabditis elegans/efectos de los fármacos , Citocinas/genética , Citocinas/metabolismo , Regulación de la Expresión Génica/efectos de los fármacos , Proteínas del Helminto/genética , Proteínas del Helminto/metabolismo , Larva/efectos de los fármacos , Ratones , Ratones Endogámicos C57BL , Saponinas/química

RESUMEN

Nematode infection upregulates interleukin-4 (IL-4) and IL-13 and induces STAT6-dependent changes in gut function that promote worm clearance. IL-4 and IL-13 activate the type 2 IL-4 receptor (IL-4R), which contains the IL-13Rα1 and IL-4Rα chains. We used mice deficient in IL-13Rα1 (IL-13Rα1(-/-)) to examine the contribution of IL-13 acting at the type 2 IL-4R to immune and functional responses to primary (Hb1) and secondary (Hb2) infections with the gastrointestinal nematode parasite Heligmosomoides bakeri There were differences between strains in the IL-4 and IL-13 expression responses to Hb1 but not Hb2 infection. Following Hb2 infection, deficient mice had impaired worm expulsion and higher worm fecundity despite normal production of Th2-derived cytokines. The upregulation of IL-25 and IL-13Rα2 in Hb1- and Hb2-infected wild-type (WT) mice was absent in IL-13Rα1(-/-)mice. Goblet cell numbers and resistin-like molecule beta (RELM-ß) expression were attenuated significantly in IL-13Rα1(-/-)mice following Hb2 infections. IL-13Rα1 contributes to the development of alternatively activated macrophages, but the type 1 IL-4R is also important. Hb1 infection had no effects on smooth muscle function or epithelial permeability in either strain, while the enhanced mucosal permeability and changes in smooth muscle function and morphology observed in response to Hb2 infection in WT mice were absent in IL-13Rα1(-/-)mice. Notably, the contribution of claudin-2, which has been linked to IL-13, does not mediate the increased mucosal permeability following Hb2 infection. These results show that activation of IL-13Rα1 is critical for key aspects of the immune and functional responses to Hb2 infection that facilitate expulsion.

Asunto(s)

Heligmosomatoidea , Subunidad alfa1 del Receptor de Interleucina-13/metabolismo , Parasitosis Intestinales/metabolismo , Infecciones por Strongylida/inmunología , Animales , Femenino , Subunidad alfa1 del Receptor de Interleucina-13/genética , Parasitosis Intestinales/inmunología , Mucosa Intestinal/metabolismo , Intestinos/citología , Ratones , Ratones Endogámicos BALB C , Ratones Noqueados , Infecciones por Strongylida/parasitología

RESUMEN

The species of the genus Odilia Durette-Desset, 1973 (Heligmonellidae, Nippostrongylinae) are re-distributed among eight genera of which five are new. This classification is mainly based on certain characters of the synlophe not previously taken into account at the supraspecific level. These characters mainly include the presence or absence of a careen, the relative size of the ridges forming the careen, the development and position of ridge 1', the development of the left ridge and right ridge, and the distribution of the largest ridges. Eighteen of the 20 known species are rearranged in the following genera: Odilia sensu stricto Durette-Desset, 1973 with Odilia mackerrasae (Mawson, 1961) as type species, Chisholmia n. gen. with Chisholmia bainae (Beveridge & Durette-Desset, 1992) n. comb. as type species, Equilophos n. gen. with Equilophos polyrhabdote (Mawson, 1961) n. comb. as type species, Hasegawanema n. gen. with Hasegawanema mamasaense (Hasegawa, Miyata & Syafruddin, 1999) n. comb. as type species, Hughjonestrongylus Digiani & Durette-Desset, 2014 with Hughjonestrongylus ennisae (Smales & Heinrich, 2010) as type species, Lesleyella n. gen. with Lesleyella wauensis (Smales, 2010) n. comb. as type and sole species, Parasabanema szalayi Smales & Heinrich, 2010, and Sanduanensis n. gen. with Sanduanensis dividua (Smales, 2010) as type and sole species. Odilia uromyos Mawson, 1961 and Odilia carinatae Smales, 2008 are not included in the new classification. A key to the proposed genera is provided. The new generic arrangement follows a distribution more related to the biogeographical areas than to the host groups.

Asunto(s)

Parasitosis Intestinales/veterinaria , Muridae/parasitología , Enfermedades de los Roedores/parasitología , Infecciones por Strongylida/veterinaria , Animales , Australasia , Heligmosomatoidea/anatomía & histología , Heligmosomatoidea/clasificación , Parasitosis Intestinales/parasitología , Especificidad de la Especie , Infecciones por Strongylida/parasitología , Trichostrongyloidea/anatomía & histología , Trichostrongyloidea/clasificación

RESUMEN

Most animals are concurrently infected with multiple parasite species and live in environments with fluctuating resource availability. Resource limitation can influence host immune responses and the degree of competition between co-infecting parasites, yet its effects on individual health and pathogen transmission have not been studied for co-infected hosts. To test how resource limitation affects immune trade-offs and co-infection outcomes, we conducted a factorial experiment using laboratory mice. Mice were given a standard or low protein diet, dosed with two species of helminths (alone and in combination), and then challenged with a microparasite. Using a community ecology trophic framework, we found that co-infection influenced parasite survival and reproduction via host immunity, but the magnitude and direction of responses depended on resources and the combination of co-infecting parasites. Our findings highlight that resources and their consequence for host defenses are a key context that shapes the magnitude and direction of parasite interactions.

Asunto(s)

Coinfección , Heligmosomatoidea , Mycobacterium bovis , Nippostrongylus , Infecciones por Strongylida/parasitología , Tuberculosis/complicaciones , Animales , Ratones , Infecciones por Strongylida/complicaciones

RESUMEN

Resistance to infections with Heligmosomoides bakeri is associated with a significant quantitative trait locus (QTL-Hbnr1) on mouse chromosome 1 (MMU1). We exploited recombinant mice, with a segment of MMU1 from susceptible C57Bl/10 mice introgressed onto MMU1 in intermediate responder NOD mice (strains 1094 and 6109). BALB/c (intermediate responder) and C57Bl/6 mice (poor responder) were included as control strains and strain 1098 (B10 alleles on MMU3) as NOD controls. BALB/c mice resisted infection rapidly and C57Bl/6 accumulated heavy worm burdens. Fecal egg counts dropped by weeks 10-11 in strain 1098, but strains 1094 and 6109 continued to produce eggs, harbouring more worms when autopsied (day 77). PubMed search identified 3 genes (Ctla4, Cd28, Icos) as associated with 'Heligmosomoides' in the B10 insert. Single nucleotide polymorphism (SNP) differences in Ctla4 could be responsible for regulatory changes in gene function, and a SNP within a splice site in Cd28 could have an impact on function, but no polymorphisms with predicted effects on function were found in Icos. Therefore, one or more genes encoded in the B10 insert into NOD mice contribute to the response phenotype, narrowing down the search for genes underlying the H. bakeri resistance QTL, and suggest Cd28 and Ctla4 as candidate genes.

Asunto(s)

Resistencia a la Enfermedad/genética , Heligmosomatoidea/inmunología , Ratones Endogámicos/genética , Infecciones por Strongylida/inmunología , Animales , Antígenos CD28/genética , Antígeno CTLA-4/genética , Haplotipos , Ratones , Ratones Endogámicos BALB C , Ratones Endogámicos C57BL , Ratones Endogámicos CBA , Ratones Endogámicos NOD , Polimorfismo de Nucleótido Simple , Sitios de Carácter Cuantitativo , Infecciones por Strongylida/genética

RESUMEN

Basophils orchestrate protection against reinfections with gastrointestinal helminths and ticks, but the underlying mechanisms remain elusive. We investigated the role of Fc receptors on basophils, the antibody isotypes IgG1 and IgE, and basophil-derived IL-4/IL-13 during challenge infections with Heligmosomoides polygyrus and Nippostrongylus brasiliensis. Using mixed bone marrow chimeras, we found that activating Fc receptors on basophils were required for protective immunity but not for regulation of basophil homeostasis. Furthermore, rapid worm expulsion was impaired in IgE-deficient but not in IgG1-deficient mice. Basophils promoted the recruitment of other effector cells into the small intestine and induced expression of the antihelminthic proteins resistin-like molecule ß and mucin 5ac. Selective deletion of IL-4/IL-13 in basophils resulted in impaired worm expulsion. Collectively, our results indicate that IgE-mediated activation of basophils and the release of basophil-derived IL-4/IL-13 are critical steps in protective immunity against helminths. Therefore, development of effective vaccines against helminths should consider boosting the IL-4/IgE/basophil axis of the immune system.

Asunto(s)

Basófilos/inmunología , Citocinas/inmunología , Tracto Gastrointestinal/inmunología , Heligmosomatoidea/inmunología , Inmunoglobulina E/inmunología , Infecciones por Strongylida/inmunología , Animales , Basófilos/metabolismo , Basófilos/parasitología , Western Blotting , Citocinas/metabolismo , Citometría de Flujo , Tracto Gastrointestinal/metabolismo , Tracto Gastrointestinal/parasitología , Heligmosomatoidea/fisiología , Interacciones Huésped-Parásitos/inmunología , Inmunoglobulina E/genética , Inmunoglobulina E/metabolismo , Interleucina-13/genética , Interleucina-13/inmunología , Interleucina-13/metabolismo , Interleucina-4/genética , Interleucina-4/inmunología , Interleucina-4/metabolismo , Intestino Delgado/inmunología , Intestino Delgado/metabolismo , Intestino Delgado/parasitología , Ratones Endogámicos BALB C , Ratones Endogámicos C57BL , Ratones Noqueados , Ratones Transgénicos , Nematospiroides dubius/inmunología , Nematospiroides dubius/fisiología , Nippostrongylus/inmunología , Nippostrongylus/fisiología , Receptores Fc/genética , Receptores Fc/inmunología , Receptores Fc/metabolismo , Infecciones por Strongylida/metabolismo , Infecciones por Strongylida/parasitología , Células Th2/inmunología , Células Th2/metabolismo

RESUMEN

Host specificity is a fundamental property of parasites. Whereas most studies focus on measures of specificity on host range, only few studies have considered quantitative aspects such as infection intensity or prevalence. The relative importance of these quantitative aspects is still unclear, mainly because of methodological constraints, yet central to a precise assessment of host specificity. Here, we assessed simultaneously two quantitative measures of host specificity of Heligmosomoides glareoli and Heligmosomoides polygyrus polygyrus infections in sympatric rodent hosts. We used standard morphological techniques as well as real-time quantitative PCR and sequencing of the rDNA ITS2 fragment to analyse parasite infection via faecal sample remains. Although both parasite species are thought to be strictly species-specific, we found morphologically and molecularly validated co- and cross-infections. We also detected contrasting patterns within and between host species with regard to specificity for prevalence and intensity of infection. H. glareoli intensities were twofold higher in bank voles than in yellow-necked mice, but prevalence did not differ significantly between species (33 vs. 18%). We found the opposite pattern in H. polygyrus infections with similar intensity levels between host species but significantly higher prevalence in mouse hosts (56 vs. 10%). Detection rates were higher with molecular tools than morphological methods. Our results emphasize the necessity to consider quantitative aspects of specificity for a full view of a parasites' capacity to replicate and transmit in hosts and present a worked example of how modern molecular tools help to advance our understanding of selective forces in host-parasite ecology and evolution.

Asunto(s)

Arvicolinae/parasitología , Heligmosomatoidea/fisiología , Especificidad del Huésped , Murinae/parasitología , Enfermedades de los Roedores/parasitología , Infecciones por Strongylida/veterinaria , Animales , ADN de Helmintos/genética , ADN Espaciador Ribosómico/genética , Femenino , Heligmosomatoidea/genética , Heligmosomatoidea/aislamiento & purificación , Masculino , Nematospiroides dubius/genética , Nematospiroides dubius/aislamiento & purificación , Nematospiroides dubius/fisiología , Prevalencia , Reacción en Cadena en Tiempo Real de la Polimerasa/veterinaria , Enfermedades de los Roedores/epidemiología , Especificidad de la Especie , Infecciones por Strongylida/epidemiología , Infecciones por Strongylida/parasitología , Simpatría

RESUMEN

Intestinal helminth infections are common and of paramount economic importance in domestic animals. Available chemotherapy is limited and anthelmintic resistance is widespread in some hosts. This scenario favors the exploration of alternative methods of control, among them immune modulators. The effect of Escherichia coli LPS+Propionibacterium acnes on a primary infection of Heligmosomoides polygyrus (Trichostongyloidea) in mice has been tested. Nematode infection induced a rise of specific IgG1, both serum and intestinal, and a significant reduction in the unspecific (ConA) lymphoproliferative response. Treatment with the immune modulator (days -2, 0, 7 and 14 post infection) elicited an apparent delay of larval intramucosal development. Moreover cumulative nematode egg shedding in treated mice was significantly lower (p=0.0041). Preliminary results point toward the interest of immune modulators to control intestinal helminths.

Asunto(s)

Formación de Anticuerpos/inmunología , Lipopolisacáridos/farmacología , Propionibacterium acnes/inmunología , Infecciones por Strongylida/inmunología , Animales , Anticuerpos Antihelmínticos/análisis , Anticuerpos Antihelmínticos/sangre , Formación de Anticuerpos/efectos de los fármacos , Heces/parasitología , Heligmosomatoidea/inmunología , Factores Inmunológicos/farmacología , Inmunomodulación/inmunología , Intestinos/parasitología , Intestinos/patología , Larva , Ratones Endogámicos BALB C , Recuento de Huevos de Parásitos , Carga de Parásitos

RESUMEN

Protein deficiency impairs local and systemic immune responses to Heligmosomoides bakeri infection but little is known about their individual and interactive impacts on tissue architecture of maternal lymphoid (thymus, spleen) and visceral (small intestine, kidney, liver, pancreas) organs during the demanding period of lactation. Using a 2 × 2 factorial design, pregnant CD1 mice were fed a 24% protein sufficient (PS) or a 6% protein deficient (PD) isoenergetic diet beginning on day 14 of pregnancy and were infected with 100 H. bakeri larvae four times or exposed to four sham infections. On day 20 of lactation, maternal organs were examined histologically and serum analytes were assayed as indicators of organ function. The absence of villus atrophy in response to infection was associated with increased crypt depth and infiltration of mast cells and eosinophils but only in lactating dams fed adequate protein. Infection-induced lobular liver inflammation was reduced in PD dams, however, abnormalities in the kidney caused by protein deficiency were absent in infected dams. Bilirubin and creatinine were highest in PD infected mice. Infection-induced splenomegaly was not due to an increase in the lymphoid compartment of the spleen. During lactation, infection and protein deficiency have interactive effects on extra-intestinal pathologies.

Asunto(s)

Heligmosomatoidea/inmunología , Helmintiasis/inmunología , Parasitosis Intestinales/inmunología , Deficiencia de Proteína/fisiopatología , Infecciones por Strongylida/inmunología , Animales , Modelos Animales de Enfermedad , Duodeno/patología , Femenino , Helmintiasis/parasitología , Parasitosis Intestinales/parasitología , Intestino Delgado/patología , Riñón/patología , Lactancia , Hígado/patología , Ratones , Bazo/patología , Infecciones por Strongylida/parasitología

RESUMEN

Macrophages (MΦs) colonize tissues during inflammation in two distinct ways: recruitment of monocyte precursors and proliferation of resident cells. We recently revealed a major role for IL-4 in the proliferative expansion of resident MΦs during a Th2-biased tissue nematode infection. We now show that proliferation of MΦs during intestinal as well as tissue nematode infection is restricted to sites of IL-4 production and requires MΦ-intrinsic IL-4R signaling. However, both IL-4Rα-dependent and -independent mechanisms contributed to MΦ proliferation during nematode infections. IL-4R-independent proliferation was controlled by a rise in local CSF-1 levels, but IL-4Rα expression conferred a competitive advantage with higher and more sustained proliferation and increased accumulation of IL-4Rα(+) compared with IL-4Rα(-) cells. Mechanistically, this occurred by conversion of IL-4Rα(+) MΦs from a CSF-1-dependent to -independent program of proliferation. Thus, IL-4 increases the relative density of tissue MΦs by overcoming the constraints mediated by the availability of CSF-1. Finally, although both elevated CSF1R and IL-4Rα signaling triggered proliferation above homeostatic levels, only CSF-1 led to the recruitment of monocytes and neutrophils. Thus, the IL-4 pathway of proliferation may have developed as an alternative to CSF-1 to increase resident MΦ numbers without coincident monocyte recruitment.

Asunto(s)

Homeostasis , Interleucina-4/metabolismo , Factor Estimulante de Colonias de Macrófagos/metabolismo , Macrófagos/citología , Macrófagos/metabolismo , Transducción de Señal , Inmunidad Adaptativa/inmunología , Animales , Proliferación Celular , Filarioidea/fisiología , Heligmosomatoidea/fisiología , Inflamación/parasitología , Inflamación/patología , Intestinos/inmunología , Intestinos/parasitología , Intestinos/patología , Activación de Macrófagos , Ratones , Ratones Endogámicos BALB C , Ratones Endogámicos C57BL , Neutrófilos/metabolismo , Receptor de Factor Estimulante de Colonias de Macrófagos/metabolismo , Receptores de Interleucina-4/metabolismo

RESUMEN

Despite immense efforts to combat malaria in tropical and sub-tropical regions, the potency of this vector-borne disease and its status as a major driver of morbidity and mortality remain undisputed. We develop an analytical pipeline for characterizing Plasmodium infection in a mouse model and identify candidate urinary biomarkers that may present alternatives to immune-based diagnostic tools. We employ (1)H nuclear magnetic resonance (NMR) profiling followed by multivariate modeling to discover diagnostic spectral regions. Identification of chemical structures is then made on the basis of statistical spectroscopy, multinuclear NMR, and entrapment of candidates by iterative liquid chromatography (LC) and mass spectrometry (MS). We identify two urinary metabolites (i) 4-amino-1-[3-hydroxy-5-(hydroxymethyl)-2,3-dihydrofuran-2-yl]pyrimidin-2(1H)-one, (ii) 2-amino-4-({[5-(4-amino-2-oxopyrimidin-1(2H)-yl)-4-hydroxy-4,5-dihydrofuran-2-yl]methyl}sulfanyl)butanoic acid that were detected only in Plasmodium berghei-infected mice. These metabolites have not been described in the mammalian or parasite metabolism to date. This analytical pipeline could be employed in prospecting for infection biomarkers in human populations.

Asunto(s)

Biomarcadores/metabolismo , Malaria/diagnóstico , Malaria/metabolismo , Metaboloma , Metabolómica , Animales , Biomarcadores/sangre , Biomarcadores/química , Biomarcadores/orina , Peso Corporal , Coinfección/sangre , Coinfección/complicaciones , Coinfección/metabolismo , Coinfección/parasitología , Modelos Animales de Enfermedad , Femenino , Heligmosomatoidea/fisiología , Hematócrito , Humanos , Espectroscopía de Resonancia Magnética , Malaria/complicaciones , Malaria/parasitología , Ratones , Plasmodium berghei/fisiología , Infecciones por Strongylida/sangre , Infecciones por Strongylida/complicaciones , Infecciones por Strongylida/parasitología , Infecciones por Strongylida/orina

RESUMEN

It's a wormy world. All natural vertebrate populations are subject to infection and re-infection with helminth parasites (Stoll 1947). Even in humans, around one billion people in developing nations are infected by one or several of a range of helminth parasites (Lustigman et al. 2012). Infection by worms is therefore the norm and is reflected in vertebrate immune responses. Thus, there is probably little point in generating an inflammatory response to clear every last worm, with ensuing collateral damage to our own tissue, when rapid re-infection from the environment by another worm is pretty much assured. Instead, the vertebrate immune system modifies its response to worms, controlling (but not always clearing) these infections and at the same time limiting damage to host tissue caused by inflammatory immune responses (Jackson et al. 2009). The immune system, however, has to fight battles on several fronts and, while fighting a prolonged war of attrition against helminth parasites, it also has to protect against periodic invasion by bacteria, where a rapid response to kill invading microbes before they spread is essential. In this issue of Molecular Ecology, Friberg et al. (2013) ask what effect worm infections have on a host's ability to mount antimicrobial responses.

Asunto(s)

Heligmosomatoidea/inmunología , Interacciones Huésped-Parásitos/inmunología , Inmunidad Innata/inmunología , Murinae/parasitología , Infecciones por Nematodos/inmunología , Receptores Toll-Like/inmunología , Animales