A importância de imunoglobulina E (IgE) na mucosa intestinal para a eliminação de nematódeos parasitos gastrointestinais

This review discusses experimental evidences that indicate the IgE participation on the effector mechanisms that leads to gastrointestinal nematode elimination. Data discussed here showed that, for most experimental models, the immune response involved in nematode elimination is regulated by Th-2 type cytokines (especially IL-4). However, the mechanism(s) that result in worm elimination is not clear and might be distinct in different nematode species. Parasite specific IgE production, especially the IgE produced by the intestinal mucosae or associated lymphoid organs could participate in the intestinal elimination of Trichinella spiralis from infected rats. Intestinal IgE may also be important to the protective mechanism developed against other gastrointestinal nematodes that penetrate the murine duodenum mucosa tissue, such as Strongyloides venezuelensis and Heligmosomoides polygyrus. At least in Trichinella spiralis infected rats, the results indicated that intestinal IgE might work independently from mast cell degranulation for worm elimination.Esta revisão pretende discutir as evidências experimentais indicando que IgE tem participação no processo que resulta na eliminação de nematódeos parasitos gastrointestinais. Os dados da literatura revelam que, na maioria dos modelos experimentais de infecção em murinos, a resposta imune que induz a eliminação de nematódeos é controlada por citocinas Th-2 (especialmente IL-4). Entretanto, o exato mecanismo(s) responsável pelo fenômeno ainda não foi completamente esclarecido e, provavelmente, varia em diferentes espécies de nematódeos. A produção de IgE específica contra antígenos do parasito, especialmente a IgE produzida localmente (mucosa intestinal ou órgãos linfáticos associados), tem grande importância para eliminação de T. spiralis do intestino de ratos infectados. IgE intestinal pode também estar envolvida na eliminação de vermes adultos de outros nematódeos que penetram na mucosa intestinal da região duodenal, como S. venezuelensis e H. polygyrus. No caso da infecção de T. spiralis em ratos, os resultados obtidos sugerem ainda que IgE intestinal pode participar da eliminação dos vermes intestinais através de mecanismos que independem de mastócitos

Criação em larga escala de Biomphalaria tenagophila

An efficient method for breeding Biomphalaria tenagophila (Taim lineage/RS) was developed over a 5-year-period (2005-2010). Special facilities were provided which consisted of four cement tanks (9.4 x 0.6 x 0.22 m), with their bottom covered with a layer of sterilized red earth and calcium carbonate. Standard measures were adopted, as follows: each tank should contain an average of 3000 specimens, and would be provided with a daily ration of 35,000 mg complemented with lettuce. A green-house effect heating system was developed which constituted of movable dark canvas covers, which allowed the temperature to be controlled between 20 - 24 ºC. This system was essential, especially during the coldest months of the year. Approximately 27,000 specimens with a diameter of 12 mm or more were produced during a 14-month-period. The mortality rates of the newly-hatched and adult snails were 77% and 37%, respectively. The follow-up of the development system related to 310 specimens of B. tenagophila demonstrated that 70-day-old snails reached an average of 17.0 ± 0.9 mm diameter. The mortality rates and the development performance of B. tenagophila snails can be considered as highly satisfactory, when compared with other results in literature related to works carried out with different species of the genus Biomphalaria, under controlled laboratory conditions.Foi desenvolvido um método eficiente de criação em larga escala de Biomphalaria tenagophila (linhagem Taim/RS) durante o período de 2005-2010. Foi concebida uma instalação que consiste de quatro tanques de alvenaria (9,4 x 0,6 x 0,22) com fundos recobertos por uma mistura constituída de terra vermelha esterilizada e carbonato de cálcio. Foi padronizado que cada tanque de criação conteria em média 3.000 exemplares e receberia diariamente 35.000 mg de ração e alface como complemento. O desenvolvimento de um sistema de aquecimento por efeito estufa constituído de lonas escuras móveis permitiu controlar a temperatura entre 20 a 24 ºC, sistema essencial principalmente nos meses mais frios. Durante o período de 14 meses foram produzidos aproximadamente 27.000 exemplares com diâmetros superiores a 12 mm. As taxas de mortalidade dos caramujos recém-eclodidos e adultos foram de 77% e 37%, respectivamente. O acompanhamento do ritmo de crescimento de 310 B. tenagophila demonstrou que caramujos com 70 dias de idade alcançaram em média 17,0 ± 0,9 mm de diâmetro. As taxas de mortalidade e o desempenho de crescimento de caramujos do gênero B. tenagophila podem ser considerados altamente satisfatórios, comparando-se com os resultados da literatura realizados com espécies do gênero Biomphalaria em condições controladas de laboratório

Lower production of IL-17A and increased susceptibility to Mycobacterium bovis in mice coinfected with Strongyloides venezuelensis

The presence of intestinal helminths can down-regulate the immune response required to control mycobacterial infection. BALB/c mice infected with Mycobacterium bovis following an infection with the intestinal helminth Strongyloides venezuelensis showed reduced interleukin-17A production by lung cells and increased bacterial burden. Also, small granulomas and a high accumulation of cells expressing the inhibitory molecule CTLA-4 were observed in the lung. These data suggest that intestinal helminth infection could have a detrimental effect on the control of tuberculosis (TB) and render coinfected individuals more susceptible to the development of TB

Infection with Strongyloides venezuelensis Induces Transient Airway Eosinophilic Inflammation, an Increase in Immunoglobulin E, and Hyperresponsiveness in Rats

Infection by nematode parasites with a pulmonary migration in their life cycle and allergic asthma are two highly prevalent diseases in humans; therefore, one may expect both may occur concomitantly. There is a predominant and essential role of Th2 lymphocytes in the mechanisms underlying the control of parasite elimination as well as in the pathology observed in the asthmatic lung. The consequences of such situations have been explored, with controversial results, justifying the development of experimental models in which the relationship between allergic airway inflammation and helminth infection might be evaluated. The present work describes the inflammatory, humoral, and functional changes that occur in the lung of rats after single (subcutaneous inoculation of 1,500 L3 larvae) or multiple (five weekly subcutaneous inoculations of 1,500 L3 larvae) Strongyloides venezuelensis infections. The results show that the migration of S. venezuelensis larvae through the lungs of infected rats induces a local eosinophilic inflammation process which is mostly focal and parenchymal for rats infected a single time and which is peribronchial after multiple infections. The inflammatory process is accompanied by mucus hypersecretion, thickening of bronchial epithelial and muscle layers, and local increase in immunoglobulin E concentrations that peak after 5 to 7 days and are resolved after 12 days of single or multiple infections. The peak of lung immunopathologic changes observed in infected rats coincides with lung airway hyperresponsiveness (AHR), a key functional alteration in asthma. We propose that this experimental model is ideal to carry out further studies on immunoprotection against nematode infection versus immunopathology of allergic airway inflammation

Platelet-Activating Factor Receptor Deficiency Delays Elimination of Adult Worms but Reduces Fecundity in Strongyloides venezuelensis-Infected Mice

We describe the parasitological kinetics and histopathological and immunological alterations in platelet-activating factor receptor-deficient (PAFR(−/−)) and wild-type mice after a single Strongyloides venezuelensis infection (subcutaneous inoculation of 500 L3 larvae). There was no difference in the numbers of worms that reached and became established in the small intestines of PAFR(−/−) and wild-type mice. However, at 12 days after infection, significantly more worms were recovered from PAFR(−/−) mice. Although PAFR(−/−) infected mice showed a delay in elimination of adult worms, worms established in the small intestine of these mice produced a significantly lower number of eggs due to a reduction in worm fecundity. There were also significant reductions in the number of circulating and tissue eosinophils and tumor necrosis factor levels in the small intestines of PAFR(−/−) mice infected for 7 days compared to the number and level in wild-type mice. Histological analysis confirmed the reduced inflammatory process and revealed that the PAFR(−/−) mice had a smaller number of goblet cells. The concentrations of the type 2 cytokines interleukin-4 (IL-4), IL-5, and IL-10 were lower in small intestine homogenates and in supernatants of antigen-stimulated lymphocytes from spleens or mesenteric lymph nodes of PAFR(−/−) mice than in the corresponding preparations from wild-type mice. Thus, in S. venezuelensis-infected PAFR(−/−) mice, decreased intestinal inflammation is associated with enhanced worm survival but decreased fecundity. We suggest that although a Th2-predominant inflammatory response decreases worm survival, the worm may use factors produced during this response to facilitate egg output and reproduction. PAFR-mediated responses appear to modulate these host-derived signals that are important for worm fecundity

<i>Schistosoma</i> and <i>Leishmania</i>: An Untold Story of Coinfection

A remarkable characteristic of infectious diseases classified as Neglected Tropical Diseases (NTDs) is the fact that they are mostly transmitted in tropical and subtropical regions with poor conditions of sanitation and low access to healthcare, which makes transmission areas more likely to overlap. Two of the most important NTDs, schistosomiasis and leishmaniasis, despite being caused by very different etiological agents, have their pathogenesis heavily associated with immune-mediated mechanisms, and Schistosoma spp. and Leishmania spp. have been shown to simultaneously infect humans. Still, the consequences of Schistosoma–Leishmania coinfections remain underexplored. As the inflammatory processes elicited by each one of these parasites can influence the other, several changes have been observed due to this coinfection in naturally infected humans, experimental models, and in vitro cell assays, including modifications in susceptibility to infection, pathogenesis, prognostic, and response to treatment. Herein, we review the current knowledge in Schistosoma–Leishmania coinfections in both human populations and experimental models, with special regard to how schistosomiasis affects tegumentary leishmaniasis, discuss future perspectives, and suggest a few steps to further improve our understanding in this model of parasite–host–parasite interaction

Experimental Infection with Schistosoma mansoni in CCR5-Deficient Mice Is Associated with Increased Disease Severity, as CCR5 Plays a Role in Controlling Granulomatous Inflammation▿

The plasma level of the chemokine CCL3 is elevated in patients with chronic severe schistosomiasis mansoni. We have previously shown that CCL3−/− mice with experimental infection showed diminished pathology and worm burden compared to those of wild-type (WT) mice. To elucidate further the role of CC chemokines during schistosomiasis mansoni infection, we evaluated the course of infection in C57BL/6J mice deficient in CCR5, one of the receptors for CCL3. The CCR5 deficiency proved to be remarkably deleterious to the host, since mortality rates reached 70% at 14 weeks postinfection in CCR5−/− mice and 19% in WT mice. The increased lethality was not associated with an increased parasite burden, since similar numbers of eggs and adult worms were found in mice from both groups. Liver granulomas of chronically infected CCR5−/− mice were larger and showed greater numbers of cells and collagen deposition than liver granulomas from WT mice. This was associated with higher levels of production of intereleukin-5 (IL-5), IL-13, CCL3, and CCL5 in infected CCR5−/− mice than in infected WT mice. Moreover, at 8 weeks after infection, just before changes in pathology and mortality, the numbers of FoxP3-positive cells were lower in liver granulomas of CCR5−/− mice than in WT mice. In conclusion, the CCR5 deletion is deleterious to mice infected with Schistosoma mansoni, and this is associated with enhanced fibrosis and granulomatous inflammation

Molluscan response to parasite:Biomphalariaand Schistosoma mansoniinteraction

Submitted by Nuzia Santos ([email protected]) on 2013-07-01T18:24:53Z No. of bitstreams: 1 81 NEGRÃO-CORRÊA D.pdf: 1794097 bytes, checksum: 580b4a04b04ee172c26f5b3a7b46b1f5 (MD5)Made available in DSpace on 2013-07-01T18:24:53Z (GMT). No. of bitstreams: 1 81 NEGRÃO-CORRÊA D.pdf: 1794097 bytes, checksum: 580b4a04b04ee172c26f5b3a7b46b1f5 (MD5) Previous issue date: 2007(FAPEMIG), and PRONEX (CNPq/FAPEMIG)Universidade Federal de Minas. Instituto de Ciências Biológicas. Departamento de Parasitologia. Belo Horizonte, MG, Brazil.Universidade Federal de Minas. Instituto de Ciências Biológicas. Departamento de Parasitologia. Belo Horizonte, MG, Brazil.Universidade Federal de Minas. Instituto de Ciências Biológicas. Departamento de Parasitologia. Belo Horizonte, MG, Brazil.Universidade Federal de Minas. Instituto de Ciências Biológicas. Departamento de Parasitologia. Belo Horizonte, MG, Brazil.Fundação Oswaldo Cruz. Centro de Pesquisas Gonçalo. Salvador, BA, Brazil.Fundação Oswaldo Cruz. Centro de Pesquisas René Rachou. Belo Horizonte, MG, Brazil / Santa Casa de Misericórida de Belo Horizonte. Belo Horizonte, MG, Brazil.Digenetic trematodes use molluscs, almost always a Gastropoda, in their evolutive cycle, as intermediary hosts. The genus Schistosoma, with three main species that infect humans - S. mansoni, S. japonicum, and S. haematobium – shows a prevalence of 200 million patients in various countries worldwide, and 600 million people are still at risk of infection. S. mansoniis the most prevalent species, and Biomphalariasnails are its intermediary hosts. Although the campaigns of schistosomiasis control based on chemotherapy havereduced the morbidity and prevalence of this disease, transmission continues in almost all the areas submitted to intervention. One of the factors that has influence on the susceptibility of Biomphalaria to S. mansoni infection is ability of the host internal defense system (IDS) to recognize and destroy the parasite. In Biomphalaria, the IDS is composed of cellular elements named hemocytes that act jointly with soluble components present in hemolymph, which could affect directly the larvae, or act in the recognition of the parasite, and activation of hemocytes. The susceptibility level of the mollusc has been attributed to the hemocyte capacity of involving and destroying the parasite, and this will be the centre of interest of this review. The study of S. mansoni and Biomphalaria interaction in resistant snail strains is important not only due to the academic-scientific value of this fascinating research area, but also to the potentially possible alternatives for the control of this endemi