Using the model cestode Taenia crassiceps for the study of cysticercosis.

Taenia solium is the aetiological agent of taeniasis/cysticercosis, one of the most severe neglected tropical diseases (NTD) according to the World Health Organization (WHO). The life cycle of T. solium alternates between pigs (intermediate host) and humans (definitive host). In addition, humans can act as accidental intermediate hosts if they ingest infective eggs. In this case, the most severe condition of the disease occurs when parasites invade the central nervous system, causing neurocysticercosis (NCC). The complexity of the life cycle of T. solium imposes a barrier to study this pathogen thoroughly. Thus, related species, such as T. crassiceps are commonly used. Due to its capacity to multiply asexually, T. crassiceps can be maintained by serial passage in laboratory mice in standard biosecurity level facilities. In addition, an in vitro system to generate cysticerci in the presence of feeder cells has been recently developed. Despite model species display biological differences with their zoonotic counterparts, they have historically helped to understand the biology of the related pathogenic species and hence, generate improvements in NTD detection and control. In this chapter, we describe the procedures to carry out both in vivo and in vitro systems for T. crassiceps in the laboratory.

In vitro system for the growth and asexual multiplication of Taenia crassiceps cysticerci.

Taenia solium is the aetiological agent of cysticercosis, a zoonosis that causes severe health and economic losses across Latin America, Africa and Asia. The most serious manifestation of the disease is neurocysticercosis, which occurs when the larval stage (cysticercus) establishes in the central nervous system. Using Taenia crassiceps as an experimental model organism for the study of cysticercosis, we aimed to identify the in vitro conditions necessary to allow parasite development at the short- and long terms. First, cysticerci were incubated for 15 days in different media and parasite densities. The number of buddings and cysticerci diameter were measured to evaluate asexual multiplication and parasite growth, respectively. Vitality was determined by trypan blue staining and morphology analysis. As a result, high cysticerci density and medium containing FBS and the excretion/secretion (E/S) products of feeder cells induced parasite survival, growth and multiplication. Then, the long-term (5 weeks) incubation of the parasites in co-culture with feeder cells was evaluated. Consequently, the mammalian cell lines induced a significant increase in total parasite volume while axenic cultures did not show any statistically significant change over time. In this study, the proper conditions to maintain T. crassiceps in vitro are described for the first time in a simpler and more controlled setting other than experimental infections. In addition, it was shown that cysticerci growth, survival and asexual multiplication depend on a complex network of secreted factors from both parasite and host.

Transcriptome profiling of Cysticercus Pisiformis provides insight into responses to host bile acids.

Bile acids in host intestine activate larvae of tapeworms and facilitate its invasion. However, the mechanism underlying this process is poorly understood. In order to better understand responses of tapeworms to host biles, we used RNA-Seq profiling method to study the transcriptomes of Cysticercus Pisiformis (larvae of Taenia Pisiformis) after host bile acid treatment. A total of 338.32 million high-quality clean reads were obtained by Illumina Hiseq platform. Totally, 62,009 unigenes were assembled, 38,382 of which were successfully annotated to known databases. A total of 9324 unigenes were identified as differentially expressed genes (DEGs), of which 5380 and 3944 genes were up- and down-regulated in the group treated with bile acids, respectively. Gene Ontology analysis revealed that biosynthesis and energy metabolism potential were significantly strengthened after host bile treatment in C. pisiformis. Similarly, KEGG pathway analysis revealed an enrichment of pathways related to lipid metabolism and carbohydrate metabolism. Among them, 'AMPK signaling pathway' which is critical in balancing cellular energy, was significantly enriched after bile acids activation. In addition, pathways of 'Fatty acid biosynthesis', 'Fatty acid elongation', 'Starch and sucrose metabolism', and 'glycolysis gluconeogenesis' were also significantly changed after bile acid treatment. qRT-PCR analysis confirmed the differential abundances of some key genes in these pathways. Our data suggest that host bile acids remarkably promote the pathways of energy metabolism of this parasite and regulate the genes involved in balancing lipid metabolism and carbohydrate metabolism. These findings provide new insights on the lifecycle of Taenia parasites.

Evagination of metacestodes of the WFU strain of Taenia crassiceps and evaluation of the impact of immune suppression of hamsters during tapeworm development.

Taeniosis-cysticercosis caused by Taenia crassiceps (Zeder, 1800) is a useful experimental model for biomedical research, in substitution of Taenia solium Linnaeus, 1758, studied during decades to develop effective vaccination, novel anti-helminthic drugs and diagnostic tools. Cysticercosis in mouse (Mus musculus Linnaeus) is achieved by the larval subculturing of the Wake Forest University (WFU) strain of T. crassiceps. Golden hamster, Mesocricetus auratus (Waterhouse), has been shown to be the most suitable host for adult forms of parasite in experimental taeniosis. Metacestodes of T. crassiceps WFU multiply by budding without restrictions once inoculated into the mouse, while the number of tapeworms developed from these larvae in hamsters remains highly variable. Three objectives have been proposed to improve the infection of T. crassiceps WFU in hamsters: (1) to re-evaluate the need of immune suppression; (2) to investigate the advantage of infecting hamsters with metacestodes with in vitro protruded scolices; and (3) to compare a number of tapeworms developed from metacestodes subcultured in hamsters against those proliferated in mice. Our results demonstrated that when the evagination of murine metacestodes was high, the number of T. crassiceps WFU adults obtained from hamsters was also high. Immunosuppressive treatment remains relevant for this experimental rodent model. The hamster-to-hamster cysticercosis-taeniosis by T. crassiceps overcame the mouse-to-hamster model in the yield of adult specimens. In vitro scolex evagination and metacestode asexual proliferation in hamsters place this rodent model by T. crassiceps WFU as the most affordable experimental models with taeniids.

Partial inhibition of the main energetic pathways and its metabolic consequences after in vivo treatment with benzimidazole derivatives in experimental neurocysticercosis.

Benzimidazole derivatives such as albendazole (ABZ) and mebendazole are important molecules used in helminthic treatment. Neurocysticercosis is the main cause of acquired epilepsy throughout the world and is currently treated with ABZ. New molecules have been studied in order to aid in the treatment of this neglected tropical disease, among them RCB15 and RCB20. The aim of this study was to evaluate the metabolic impact of RCB15 and RCB20 on Taenia crassiceps cysticerci intracranially inoculated in Balb/c mice. Thirty days after the inoculation the mice were treated with 50 mg kg-1 of RCB15, RCB20, ABZ or NaCl 0.9%. The euthanasia and cysticerci removal were performed 24 h after the treatment. The cysticerci were analysed through high performance liquid chromatography. After the treatments, there was an impairment in the main energetic pathways such as glycolytic pathway, homolactic fermentation or in mitochondrion energy production detected through the decrease in pyruvate, lactate, oxaloacetate, malate and fumarate concentrations. This induced the parasite to resort to alternative energetic pathways such as proteins catabolism, propionate fermentation and fatty acids oxidation. Therefore, benzimidazole derivatives are a promising alternative to ABZ use as they also reach the brain tissue and induce a metabolic stress in the cysticerci.

Proteomic profile associated with cell death induced by androgens in Taenia crassiceps cysticerci: proposed interactome.

Androgens have been shown to exert a cysticidal effect upon Taenia crassiceps, an experimental model of cysticercosis. To further inquire into this matter, the Taenia crassiceps model was used to evaluate the expression of several proteins after testosterone (T4) and dihydrotestosterone (DHT) in vitro treatment. Under 2-D proteomic maps, parasite extracts were resolved into approximately 130 proteins distributed in a molecular weight range of 10-250 kDa and isoelectrical point range of 3-10. The resultant proteomic pattern was analysed, and significant changes were observed in response to T4 and DHT. Based on our experience with electrophoretic patterns and proteomic maps of cytoskeletal proteins, alteration in the expression of isoforms of actin, tubulin and paramyosin and of other proteins was assessed. Considering that androgens may exert their biological activity in taeniids through the non-specific progesterone receptor membrane component (PGRMC), we harnessed bioinformatics to propose the identity of androgen-regulated proteins and establish their hypothetical physiological role in the parasites. These analyses yield a possible explanation of how androgens exert their cysticidal effects through changes in the expression of proteins involved in cytoskeletal rearrangement, dynamic vesicular traffic and transduction of intracellular signals.

Plasma Paraoxonase, Sphingosine-1-phosphate, Total Sialic Acid, and Heat Shock Protein-27 in the Liver of the Sheep Naturally Infected with Cysticercus Tenuicollis: Evidence on Pathological Changes.

The present study aimed to investigate whether sphingosine 1 phosphate (S1P), paraoxonase (PON), total sialic acid (TSA), and heat shock protein-27 (HSP27) are altered in the sheep during infection of the liver with Cysticercus tenuicollis. This study was conducted on40 healthy sheep and40 sheep with Cysticercus tenuicollis infection. The infected and non-infected animals were selected based on the observation of severe Cysticercus tenuicollis infection in the liver and absence of any hepatic cysts, respectively. All parameters were measured in serum and plasma. The results revealed a significant decrease (P<0.01) in PON, TSA, and albumin (Alb) in the infected group, compared with those in the healthy one. Furthermore, the infected sheep had a significant increase (P<0.01) in S1P, HSP-27, malondialdehyde (MDA), total bilirubin, and unconjugated bilirubin as compared with those in their non-infected counterparts. Moreover, no significant change was observed in total plasma protein level in the infected animals in comparison to that in the healthy ones. The low levels of TSA and Alb revealed liver damage in the infected sheep. Moreover, the PON reduction might have resulted from hepatic steatosis and MDA enhancement. Meanwhile, S1P elevation could be attributed to the activation of platelets. In addition, HSP-27 increase was ascribed to the disease-induced stress conditions.

In vivo treatment of experimental neurocysticercosis with praziquantel nanosuspensions-a metabolic approach.

Neurocysticercosis is the most common parasitic infection of the nervous system and currently represents a serious public health issue in many regions of Latin America, Asia, and Africa. To date, praziquantel is one of the chosen drugs for the treatment of neurocysticercosis. Its mechanism of action is based on the inhibition of different biochemical pathways within the parasite which contribute to its death. Thus, the aim of this work was to analyze, for the first time, whether the nanoformulations of praziquantel would modify the energetic pathway of Taenia crassiceps cysticerci, after an intracranial inoculation in BALB/c mice. Praziquantel nanosuspensions were formulated with polyvinyl alcohol, poloxamer 188, and poloxamer 407, as stabilizers. These formulations exhibited particle size in a range of 74-285 nm and zeta potential values in a range of - 8.1/- 13.2 depending on the type of stabilizer. Physical stability study at both 4 ± 2 and 25 ± 2 °C indicated that praziquantel (PZQ) nanoparticles were stable in terms of solubility and particle size after 120-day storage. In vivo studies demonstrated that those nanosystems were able to produce significant modifications on the concentrations of oxaloacetate, citrate, pyruvate, alpha-ketoglutarate, malate, succinate, lactate, beta-hydroxybutyrate, fumarate, and propionate involved in the metabolism of Taenia crassiceps cysticerci. Therefore, these nanoformulations may be considered as a promising tool to deliver praziquantel to the brain for the effective management of neurocysticercosis.

Fate of uptaken host proteins in Taenia solium and Taenia crassiceps cysticerci.

During the study of host-parasite relationships in taeniid parasite diseases, including cysticercosis and hydatidosis, reports have described the presence of host proteins in the cyst fluid and tissue of metacestodes. However, the fate or role of host elements inside the parasite remains barely explored. After the publication of genomes of four cestode species, it became clear that these organisms possess a limited biosynthetic capability. The initial goal of the present study was to determine if uptaken host proteins could be a source of essential amino acids for cysticerci. To track the utilization of uptaken proteins, we added metabolically labeled IgG-3H and GFP-3H to the culture medium of Taenia crassiceps cysticerci. Incorporation of labeled amino acid was evaluated by fluorography in cysticerci extracts. Our results showed that the use of uptaken proteins by cysticerci as a source of amino acids appeared negligible. Exploring alternative fates for the host proteins, proteomic analysis of the protein matrix in calcareous corpuscles was carried out. Since T. crassiceps does not contain calcareous corpuscles, proteomic analyses were performed in corpuscles of Taenia solium cysticerci. Our results demonstrated that host proteins represented approximately 70% of protein content in the calcareous corpuscles. The presence of the two major uptaken host proteins, namely albumin and IgG, was also demonstrated by Western blot in the matrix of corpuscles. Our findings strongly suggested that the uptake and disposal of host proteins involve calcareous corpuscles, expanding the physiological role of these mineral concretions to a far more important level than previously proposed.

Experimental neurocysticercosis: absence of IL-4 induces lower encephalitis.

METHODS: BALB/c (WT) and BALB/c (IL-4-KO) mice were inoculated intracranially with Taenia crassiceps cysticerci and euthanized at 7, 30, 60 and 90 days later, the encephala removed and histopathologically analyzed. RESULTS: The absence of IL-4 induced greater parasitism. In the initial phase of the infection, IL-4-KO showed a lower intensity in the inflammatory infiltration of polimorphonuclear cells in the host-parasite interface and intra-parenquimatous edema. The IL-4-KO animals, in the late phase of the infection, showed lower intensity of ventriculomegaly, encephalitis, and meningitis, and greater survival of the parasites in comparison with the WT animals. CONCLUSION: The absence of IL-4 induced lower inflammatory infiltration, ventriculomegaly and perivasculitis in experimental NCC.

Experimental neurocysticercosis: absence of IL-4 induces lower encephalitis / Neurocisticercose experimental: ausência de IL-4 induz menos encefalite

ABSTRACT Neurocysticercosis (NCC) is the most severe clinical manifestation of cysticercosis. One of the factors responsible for its symptomatology is the host inflammatory response. Therefore the influence of interleukin 4 (IL-4) on the induction of encephalitis in experimental NCC was evaluated. Methods BALB/c (WT) and BALB/c (IL-4-KO) mice were inoculated intracranially with Taenia crassiceps cysticerci and euthanized at 7, 30, 60 and 90 days later, the encephala removed and histopathologically analyzed. Results The absence of IL-4 induced greater parasitism. In the initial phase of the infection, IL-4-KO showed a lower intensity in the inflammatory infiltration of polimorphonuclear cells in the host-parasite interface and intra-parenquimatous edema. The IL-4-KO animals, in the late phase of the infection, showed lower intensity of ventriculomegaly, encephalitis, and meningitis, and greater survival of the parasites in comparison with the WT animals. Conclusion The absence of IL-4 induced lower inflammatory infiltration, ventriculomegaly and perivasculitis in experimental NCC.

RESUMO A Neurocisticercose (NCC) é a manifestação clínica mais severa da cisticercose, e um dos fatores responsáveis pela sintomatologia é a resposta inflamatória do hospedeiro. Desta forma avaliou-se a influência da interleucina 4 (IL-4) na indução de encefalite na NCC experimental. Métodos Camundongos das linhagens BALB/c (WT) e BALB/c (IL-4-KO) foram inoculados intracranialmente com cisticercos de Taenia crassiceps e eutanasiados aos 7, 30, 60 e 90 dias após a infecção, os encéfalos foram removidos e analisados histopatologicamente. Resultados A ausência da IL-4 induziu um maior parasitismo nos animais. Na fase inicial da infecção os animais IL-4-KO apresentaram menor intensidade tanto de infiltrado inflamatório de polimorfonucleares na interface parasito-hospedeiro quanto de edema intraparenquimatoso. Os animais IL-4-KO, na fase tardia, apresentaram menor intensidade de ventriculomegalia, encefalite, meningite e maior sobrevivência dos cisticercos em relação aos animais WT. Conclusão A ausência da IL-4 induz menos infiltrado inflamatório, ventriculomegalia e perivasculite na NCC experimental.

Cysticercus fasciolaris infection induced oxidative stress and apoptosis in rat liver: a strategy for host-parasite cross talk.

Parasitic helminths have developed various strategies to induce or inhibit apoptosis in the cells of their host, thereby modulating the host's immune response and aiding dissemination to the host. Cysticercus fasciolaris, the larval form of Taenia taeniaeformis, parasitized different intermediate hosts like rats, rabbits, etc. and is cosmopolitan in distribution. In the present study, we have investigated host-parasite interactions and the resulting effect of C. fasciolaris in the liver of rat. Histology of the infected livers showed dilation and damages of hepatic cells near the parasite. Infected liver cells showed an increase in DNA fragmentation and chromatin condensation compared to the normal liver. Acridine orange and ethidium bromide dual staining revealed the presence of apoptotic cells in the infected liver. The decline in the mitochondrial membrane potential in the infected liver suggested that the observed apoptosis is mitochondria mediated. Occurrence of an elevated level of active executioner caspases 3/7 in the infected rat liver further confirms the occurrence of apoptosis. Different antioxidant enzymes were also evaluated and revealed a notable decline in the level of glutathione and glutathione-S-transferase activity leading to the augmented generation of reactive oxygen species. Results of the present study revealed that C. fasciolaris infection leads to apoptosis in the liver of rats which may be a surviving strategy for the parasitic larvae.

Acute visceral cysticercosis by Taenia hydatigena in lambs and treatment with praziquantel.

An acute outbreak of Taenia hydatigena cysticercosis, causing mortality in 5 of 21 (23.8%) female lambs, is reported. Gross post-mortem examinations and histology showed Cysticercus tenuicollis as the cause of death. Biochemical parameters in infected lambs confirmed severe hepatitis. Praziquantel, given once at 15 mg/kg body weight (bw), was administered and a dramatic improvement in the clinical condition and biochemical parameters was observed up to 30 days following treatment.

Taenia solium taeniosis/cysticercosis and the co-distribution with schistosomiasis in Africa.

BACKGROUND: This study aimed to map the distribution of Taenia solium taeniosis/cysticercosis and the co-distribution with schistosomiasis in Africa. These two major neglected tropical diseases are presumed to be widely distributed in Africa, but currently the level of co-distribution is unclear. METHODS: A literature search on T. solium taeniosis/cysticercosis was performed to compile all known studies on the presence of T. solium and apparent prevalence of taeniosis and porcine cysticercosis in Africa. Studies were geo-referenced using an online gazetteer. A Bayesian framework was used to combine the epidemiological data on the apparent prevalence with external information on test characteristics to estimate informed district-level prevalence of taeniosis and porcine cysticercosis. Districts with T. solium taeniosis/cysticercosis presence were cross-referenced with the Global Neglected Tropical Diseases Database for schistosomiasis presence. RESULTS: The search strategies identified 141 reports of T. solium in Africa from 1985 to 2014 from a total of 476 districts in 29 countries, 20 with porcine cysticercosis, 22 with human cysticercosis, and 16 with taeniosis, in addition to 2 countries identified from OIE reports. All 31 countries were considered, on national scale, to have co-distribution with schistosomiasis. Presence of both parasites was confirmed in 124 districts in 17 countries. The informed prevalence of taeniosis and porcine cysticercosis were estimated for 14 and 41 districts in 10 and 13 countries, respectively. CONCLUSIONS: With the paucity of data, T. solium infection is grossly under-reported and expected to be more widespread than this study suggests. In areas where co-distribution occurs there is a need for increased emphasis on evaluation of integrated intervention approaches for these two helminth infections and allocation of resources for evaluating the extent of adverse effects caused by mass drug administration.

Auranofin-induced oxidative stress causes redistribution of the glutathione pool in Taenia crassiceps cysticerci.

Previously, we have studied the effect of the gold-compound auranofin (AF) on both thioredoxin-glutathione reductasa (TGR) activity and viability of Taenia crassiceps cysticerci. It was demonstrated that micromolar concentrations of AF were high enough to fully inhibit TGR and kill the parasites. In this work, the dynamics of changes in the glutathione pool of T. crassiceps cysticerci following the addition of AF, was analyzed. A dose-dependent decrease in the internal glutathione concentration, concomitant with an increase in ROS production was observed. These changes were simultaneous with the formation of glutathione-protein complexes and the export of glutathione disulfide (GSSG) to the culture medium. Incubation of cysticerci in the presence of both AF and N-acetyl cysteine (NAC) prevents all the above changes, maintaining cysticerci viability. By contrast, the presence of both AF and buthionine sulfoximine (BSO) resulted in a potentiation of the effects of the gold compound, jeopardizing cysticerci viability. These results suggest the lethal effect of AF on T. crassiceps cysticerci, observed at micromolar concentrations, can be explained as a consequence of major changes in the glutathione status, which results in a significant increase in the oxidative stress of the parasites.

[Imaging characteristics of different types of cerebral cysticercosis].

OBJECTIVE: To study the imaging characteristics of different types of cerebral cysticercosis. METHODS: The CT and MRI findings of 166 patients with clinical diagnostic cerebral cysticercosis were reviewed retrospectively. RESULTS: Among the 166 cerebral cysticercosis patients, there were 108 cerebral parenchyma type cases, 15 ventricles type cases, 3 meningeal type cases, and 40 mixed type cases according to the cysticerci being in the parts of the brain. The CT and MRI imaging characteristics of various types were as the following. (1) Brain parenchyma type included the cystoid subtype, encephalitis subtype, nodular or multiple ring enhancement subtype, and chronic calcification subtype. The cystoid subtype: CT showed single or multiple cystic shadow (s) with clear boundary, and the sac with a high density of scolex; MRI showed round long T1 and long T2 signals, eccentric punctate shadows inside the sac, cystic wall and scolex signals, but no significant enhancement. The encephalitis subtype: CT showed scattered low density lesions and MRI showed patchy slightly long T1 and long T2 signals, but no enhancement or irregular enhancement in the majority. The nodular or multiple ring enhancement subtype: CT scan showed low density lesions in multiple nodules, or CT enhancement scan showed multiple nodules or ring enhancement. The chronic calcification subtype: CT showed single or multiple dot-like high density single (s), and MRI showed equal or long T I and short T2 signals. (2) Ventricular type: The lesions were often in the third and fourth ventricles complicated with obstructive hydrocephalus. (3) Meningeal type: there were expand and asymmetric cerebrospinal space limitations, communicating hydrocephalus, and the enhanced scan showed leptomeningeal enhancement. (4) Mixed type: The performance was mixed as two or more types above mentioned, and there existed mixed acute and chronic phases. CONCLUSIONS: The imaging findings of the different types of cerebral cysticercosis are differ from one another. The analysis of the imaging characteristics of the different types of cerebral cysticercosis has a significance for the clinical diagnosis, treatment and prognostic judgment of cerebral cysticercosis patients.

[Clinical application of diagnostic therapy of praziquantel for suspected cere- bral cysticercosis].

OBJECTIVE: To explore the clinical application value of diagnostic therapy of praziquantel for suspected cerebral cysticercosis. METHODS: The suspected cerebral cysticercosis patients were collected and treated with the diagnostic therapy [praziquantel, 50 mg/(kg · d)], and followed up for 1-2 years. RESULTS: Totally 94 suspected cerebral cysticercosis patients were collected. After the diagnostic therapy, 78 (82.98%) cases were confirmed as cerebral cysticercosis, 13 (13.83%) were diagnosed as other diseases, and 3 (3.19%) were not definitely diagnosed. CONCLUSION: The diagnostic therapy for suspected cerebral cysticercosis can reduce or avoid the missed diagnosis and misdiagnosis in some atypical cerebral cysticercosis patients.

[Cysticercus bovis in Turkey and its importance from the public health aspect]. / Türkiye'de Cysticercus bovis ve halk sagligi yönünden önemi.

This study was conducted in order to compare the different regions according to the literature on the prevalence of bovine cysticercosis and T. saginata in Turkey. Bovine cysticercosis and T. saginata status were evaluated retrospectively. The distribution of the data obtained according to provinces and regions were showed in the Table and the minumum / maximum values of this data in different regions in the Figure. The data obtained through the literature showed that the prevalence of C. bovis and T. saginata infections are parallel in the same region. The higher prevalence of both C. bovis and T. saginata infections was determined in the Southeastern Anatolia, Eastern Anatolia and Central Anatolia regions respectively.

Edema surrounding calcified intracranial cysticerci: clinical manifestations, natural history, and treatment.

Calcified granulomas are the most common radiological finding in neurocysticercosis (10-20% of endemic populations). A small proportion serves as foci of seizure activity, which results in large numbers of persons with epilepsy. Calcified granulomas are not all the same. Some demonstrate blood-brain barrier dysfunction (magnetic resonance imaging enhancement) most likely due to the presence of inflammation, visualizable scolices, and/or gliosis. About half the patients with a recent history of seizures, positive serology, and only calcified lesions develop perilesional edema at the time of a seizure recurrence. The natural history, treatment, and pathophysiology of this phenomenon are not well studied. Episodes are usually associated with seizures or other neurological manifestations, resolve by 4-6 weeks, sometimes occur repeatedly, and usually involve a subset of the same calcifications. Treatment is supportive. Histopathological examination of one calcification associated with multiple perilesional edema episodes revealed significant inflammation and supports the concept that perilesional edema is inflammatory in nature. This most likely is due to host responses to released or newly recognized parasite antigen and/or upregulation of the host immune response. Immunosuppressive and anti-inflammatory agents may be useful in prevention and/or treatment of this phenomenon.

Changes in cyst's nuclear chromatin resulting after experimental manipulation of Taenia crassiceps mice infections: biological implications.

During some estimations of the nuclear DNA content, based on determinations propidium iodide (PI) binding through fluorocytometry for Taenia crassiceps cysticerci, significant variation in the results were found. This initial observation led to a series of experiments designed to explain the variation. These changes could be induced by the diameter of the needles in the syringes used for the mouse to mouse transfer of the cysts. Nuclei from cysts transferred through 27-gauge needles showed 30% less PI staining than those transferred through 21 gauge needles, after 2 months infections. Reduction in PI capture induced by 27-gauge needle was reversible when the cysts were maintained in their mice hosts during 5 months. Moreover, variation in PI binding to cysticercal DNA was also found when comparing parasites grown in male versus female mice. The use of agents that homogenize the chromatin structure during PI staining, allowed demonstrating that variation were entirely due to differences in the chromatin relaxation/compaction. Additional experiments demonstrated that the higher compaction is accompanied by a reduced ability of cysts to grow in the peritoneal cavity of BALB/cAnN mice. Furthermore, proteomic analysis also showed that these changes in chromatin relaxation/compaction resulted in different levels and patterns of protein expression. Our results strongly suggest that chromatin is involved in several well characterized phenomena of the T. crassiceps murine model, and open new avenues for a detailed approach to understand such a complex host-parasite relationship.