Morphological studies on the early development of Taenia taeniaeformis larvae in susceptible mice

Bortoletti, G.; Ferretti, G

doi:10.1016/0020-7519(85)90021-9

Cited by 12 publications

(11 citation statements)

References 17 publications

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“…Scattered studies of the development of metacestodes of the related Taenia spp. also indicate that they initially lack AP polarity, and develop as bladders from which one or more scolex primordia appear later [ 63 , 72 – 76 ]. The lack of AP polarity during initial metacestode development, leading to a lack of correspondence between the polarity of the oncosphere and that of the metacestode, may be a characteristic of all taeniids.…”

Section: Discussionmentioning

confidence: 99%

Comparative analysis of Wnt expression identifies a highly conserved developmental transition in flatworms

et al. 2016

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BackgroundEarly developmental patterns of flatworms are extremely diverse and difficult to compare between distant groups. In parasitic flatworms, such as tapeworms, this is confounded by highly derived life cycles involving indirect development, and even the true orientation of the tapeworm antero-posterior (AP) axis has been a matter of controversy. In planarians, and metazoans generally, the AP axis is specified by the canonical Wnt pathway, and we hypothesized that it could also underpin axial formation during larval metamorphosis in tapeworms.ResultsBy comparative gene expression analysis of Wnt components and conserved AP markers in the tapeworms Echinococcus multilocularis and Hymenolepis microstoma, we found remarkable similarities between the early stages of larval metamorphosis in tapeworms and late embryonic and adult development in planarians. We demonstrate posterior expression of specific Wnt factors during larval metamorphosis and show that scolex formation is preceded by localized expression of Wnt inhibitors. In the highly derived larval form of E. multilocularis, which proliferates asexually within the mammalian host, we found ubiquitous expression of posterior Wnt factors combined with localized expression of Wnt inhibitors that correlates with the asexual budding of scoleces. As in planarians, muscle cells are shown to be a source of secreted Wnt ligands, providing an explanation for the retention of a muscle layer in the immotile E. multilocularis larva.ConclusionsThe strong conservation of gene expression between larval metamorphosis in tapeworms and late embryonic development in planarians suggests, for the first time, a homologous developmental period across this diverse phylum. We postulate these to represent the phylotypic stages of these flatworm groups. Our results support the classical notion that the scolex is the true anterior end of tapeworms. Furthermore, the up-regulation of Wnt inhibitors during the specification of multiple anterior poles suggests a mechanism for the unique asexual reproduction of E. multilocularis larvae.Electronic supplementary materialThe online version of this article (doi:10.1186/s12915-016-0233-x) contains supplementary material, which is available to authorized users.

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Section: Discussionmentioning

confidence: 99%

Comparative analysis of Wnt expression identifies a highly conserved developmental transition in flatworms

et al. 2016

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“…Larvae establishing in the liver of rodents elicit variable degrees of inflammation during the initial 2 weeks. In susceptible mouse strains (C3H), infiltration tends to be mild, and in particular, eosinophils are absent; in addition, inflammatory cells are prevented from touching the parasite by an acellular “halo” or “perilarval amorphous material” said to resemble the Echinococcus LL . In contrast, in resistant mouse strains (Balb/c), eosinophils gain access to the interior of the “halo” by 5 dpi, and by 10‐13 dpi, the parasite is destroyed .…”

Section: Taenia Taeniaeformismentioning

confidence: 99%

“…Resistance mechanisms against effectors include the barrier function of the Echinococcus LL and possibly the early “perilarval amorphous material” apparently deployed by establishing T. taeniaeformis larvae …”

Section: How Do Larval Taeniids Evade Granulomatous Responses?mentioning

confidence: 99%

“…In susceptible mouse strains (C3H), infiltration tends to be mild, and in particular, eosinophils are absent; in addition, inflammatory cells are prevented from touching the parasite by an acellular "halo" or "perilarval amorphous material" said to resemble the Echinococcus LL. [38][39][40] In contrast, in resistant mouse strains (Balb/c), eosinophils gain access to the interior of the "halo" by 5 dpi, and by 10-13 dpi, the parasite is destroyed. 38,40,41 Strikingly, the parasite appears to be reabsorbed so that no granuloma or scar remains by 17 dpi.…”

Section: Taenia Taeniaeformismentioning

confidence: 99%

“…Resistance mechanisms against effectors include the barrier function of the Echinococcus LL 18 and possibly the early "perilarval amorphous material" apparently deployed by establishing T. taeniaeformis larvae. [38][39][40] The capacity to minimize local inflammation must rely on multiple, redundant mechanisms. Conceptually, these could operate on the recruitment, local survival and local proliferation of inflammatory cells.…”

Section: How Do L Arval Taeniids E Vade G R Anulomatous Re S P Ons mentioning

confidence: 99%

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Granulomatous responses in larval taeniid infections

Díaz

Sagasti

Casaravilla

2018

Parasite Immunology

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Granulomas are responses to persistent nonliving bodies or pathogens, centrally featuring specialized macrophage forms called epithelioid and multinucleated giant cells. The larval stages of the cestode parasites of the Taeniidae family (Taenia, Echinococcus) develop for years in fixed tissue sites in mammals. In consequence, they are targets of granulomatous responses. The information on tissue responses to larval taeniids is fragmented among host and parasite species and scattered over many decades. We attempt to draw an integrated picture of these responses in solid tissues. The intensity of inflammation around live parasites spans a spectrum from minimal to high, parasite vitality correlating with low inflammation. The low end of the inflammatory spectrum features collagen capsules proximal to the parasites and moderate distal infiltration. The middle of the spectrum is dominated by classical granulomatous responses, whereas the high end features massive eosinophil invasions. Across the range of parasite species, much observational evidence suggests that eosinophils are highly effective at killing larval taeniids in solid tissues, before and during chronic granulomatous responses. The evidence available also suggests that these parasites are adapted to inhibit host granulomatous responses, in part through the exacerbation of host regulatory mechanisms including regulatory T cells and TGF-β.

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Damage and early destruction of Taenia taeniaeformis larvae in resistant hosts, and anomalous development in susceptible hosts: A light microscopic and ultrastructural study

Bortoletti

Conchedda

Ferretti

1985

International Journal for Parasitology

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Morphological studies on the early development of Taenia taeniaeformis larvae in susceptible mice

Cited by 12 publications

References 17 publications

Comparative analysis of Wnt expression identifies a highly conserved developmental transition in flatworms

Comparative analysis of Wnt expression identifies a highly conserved developmental transition in flatworms

Granulomatous responses in larval taeniid infections

Damage and early destruction of Taenia taeniaeformis larvae in resistant hosts, and anomalous development in susceptible hosts: A light microscopic and ultrastructural study

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