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Parasite Versus Host: Pathology and Disease
Published in Eric S. Loker, Bruce V. Hofkin, Parasitology, 2023
Eric S. Loker, Bruce V. Hofkin
Another important part of the story is the manner in which many parasites shift the development of monocytes from conventional macrophages, to a more alternatively active macrophage (AAM) profile (Figure 5.25). As described in Chapter 4, AAM development is promoted by IL-4 and IL-13, secreted by various immune-system cells, including Th-2 cells. This is as opposed to classically activated macrophages, which are activated by IFN-γ, TNF, and other cytokines consistent with an inflammatory Th-1 response. AAM development can also be promoted directly by parasite-secreted molecules. The filarial worm Brugia malayi, for example, releases a molecule thought to be a homolog for macrophage migration inhibitory factor that directly promotes the AAM phenotype. In addition to their role in tissue repair, discussed in Chapter 4, AAMs help to further reduce inflammation by releasing IL-10, transforming growth factor β (TGF-β), and IL-1 decoy receptor molecules. They also produce a molecule called programmed death ligand 1 that induces anergy (an inability to become activated) in T cells. The result is reduced inflammatory damage to tissues. Mouse strains unable to develop high AAM levels, for instance, suffer from increased inflammation of the bowel when infected with the cestode Taenia crassiceps. Ordinarily, the inflammatory response is held in check, at least in part, by IL-10 secreted by AAMs. Similarly, in murine models of schistosomiasis, when AAMs are lacking, egg-mediated liver pathology never resolves and infected mice generally die.
Nitazoxanide
Published in M. Lindsay Grayson, Sara E. Cosgrove, Suzanne M. Crowe, M. Lindsay Grayson, William Hope, James S. McCarthy, John Mills, Johan W. Mouton, David L. Paterson, Kucers’ The Use of Antibiotics, 2017
Nitazoxanide has activity against some cestodes (tapeworms), and was originally developed as a veterinary tapeworm drug (Rossignol and Maisonneuve, 1984). Studies in mice demonstrated that nitazoxanide in combination with albendazole killed the larval stage of Taenia crassiceps, a finding that suggested activity in cysticercosis (Palomares-Alonso et al., 2007). However, Gonzalez et al. found that oral nitazoxanide had no cysticidal efficacy in pigs naturally infected with Taenia solium, as compared with albendazole, oxfendazole, praziquantel, or combined albendazole-praziquantel (Gonzalez et al., 2012).
Parasite Versus Host: Pathology and Disease
Published in Eric S. Loker, Bruce V. Hofkin, Parasitology, 2015
Eric S. Loker, Bruce V. Hofkin
Another important means by which parasites may lessen inflammation is through their engagement of alternatively activated macrophages (AAMs) (Figure 5.19). As we also described in Chapter 4, AAMs are also activated by Th-2 activating cytokines such IL-4 and IL-13. This is as opposed to classically activated macrophages, which are activated by IFN-γ, TNF, and other cytokines consistent with an inflammatory Th-1 response. AAMs help to polarize the immune response further toward a Th-2 profile and away from a Th-1 response by releasing IL-10, transforming growth factor β (TGFβ), and IL-1 decoy receptor molecules. They also produce a molecule called programmed death ligand 1 that induces anergy (an inability to become activated) in T cells. The result is reduced inflammatory damage to tissues. Mouse strains unable to develop high AAM levels, for instance, suffer from increased inflammation of the bowel when infected with the cestode Taenia crassiceps. Ordinarily, the inflammatory response is held in check, at least in part by IL-10 secreted by AAMs. Similarly, in murine models of schistosomiasis, when AAMs are lacking, egg-mediated liver pathology never resolves and infected mice generally die.
Plant-made vaccines against parasites: bioinspired perspectives to fight against Chagas disease
Published in Expert Review of Vaccines, 2021
Abel Ramos-Vega, Elizabeth Monreal-Escalante, Eric Dumonteil, Bernardo Bañuelos-Hernández, Carlos Angulo
On the other hand, chloroplast expression generally lacks gene silencing, which favors high protein expression yields [88]. As an example, a multicomponent recombinant vaccine expressed in tobacco plant chloroplast against the parasite Taenia solium had higher yields compared to that produced by nuclear transformation [89,90]. Importantly, both multicomponent vaccines triggered specific IgG antibodies in subcutaneously immunized mice with fresh tobacco-plant tissue. In line with these findings, Monreal-Escalante et al. [23] produced T. solium HP6/TSOL18 antigen in carrots (Daucus carota L.) as a model edible plant, which induced specific IgA and IgG responses in orally immunized mice with the callus carrot. Similarly, Fragoso et al. [24] produced a papaya-based vaccine composed of three protective peptides (S3Pvac) against cysticercosis, inducing antibodies and protection (55–66%) in orally immunized and challenged mice with Taenia crassiceps. Moreover, this vaccine induced a significant increase in IgG antibody levels in immunized pigs. Notably, the GK-1 peptide was included in the KETc7antigen sequence of T. solium vaccines [89,90] as an adjuvant because it has increased immunogenicity of a human influenza vaccine in preclinical and in vitro assays [91,92].
Recent trends in praziquantel nanoformulations for helminthiasis treatment
Published in Expert Opinion on Drug Delivery, 2022
Ana C. Mengarda, Bruno Iles, João Paulo F. Longo, Josué de Moraes
PZQ polymeric suspensions using polyvinyl alcohol (PVA), poloxamer 188 (P188), and poloxamer 407 (P407) as stabilizers were tested in mice infected with Taenia crassiceps cysticerci [41]. Oral treatments with PZQ nanosuspensions (50 mg/kg) decreased glycolysis of organic acids and boosted the partial reversal of the tricarboxylic acid cycle, the urea cycle, and the production of ketonic bodies in the worms when compared to the treatment in animals that received conventional PZQ. These data suggest that PZQ nanosuspensions had a significant effect on the energy metabolism of cysticerci in vivo.
Neurocysticercosis: the good, the bad, and the missing
Published in Expert Review of Neurotherapeutics, 2018
Arturo Carpio, Agnès Fleury, Matthew L. Romo, Ronaldo Abraham
It is also unknown whether the parasites in their racemose forms have the capacity of gemmation (asexual reproduction by budding). The appearance of clusters of grapes has long been noted; it is not known whether each ‘grape’ has the potential to individualize. In some people, new parasites are seen over time, sometimes after treatment, and generally in the proximity of the first recognized parasites. One of the reasons could be reinfection, but gemmation cannot be excluded, as it is known to occur in a closely related parasite Taenia crassiceps.