BACKGROUND Eosinophils are granulocytes that rapidly increase frequency in the bloodstream during helminthic infections and allergic responses. They are found in tissue infected by Leishmania during early disease, but their role during infection is not entirely understood. OBJECTIVES We aim to compare the disease due to Leishmania amazonensis in BALB/c and Δdbl-GATA1 mice, which lack eosinophils. METHODS BALB/c and Δdbl-GATA1 mice infected with L. amazonensis were observed for several weeks. The parasite load and dissemination pattern were assessed. FINDINGS The Δdbl-GATA1 mice developed an anticipated dissemination of L. amazonensis and a worsening disease. No differences were found in the lesion development or the parasite load in the footpad among Δdbl-GATA1 mice and BALB/c eight weeks after infection. However, nine weeks after infection, massive growth of metastatic lesions appeared in several parts of the skin in Δdbl-GATA1 mice, weeks earlier than BALB/c. We observed increased parasites in the bloodstream, probably an essential dissemination route. Thirteen weeks after infection, metastatic lesions were found in all Δdbl-GATA1 mice. MAIN CONCLUSION These results suggest a protective role of eosinophils in delaying the disease caused by L. amazonensis, although several limitations of this mice strain must be considered.

Resumo Vacinação contra Anaplasma marginale tem sido considerada uma importante estratégia de controle da anaplasmose bovina. Recentemente, camundongos imunizados com rMSP1a funcionalizada à nanotubos de carbono (MWNT) apresentaram resposta imune significante, gerando nova possibilidade para o uso da vacina inativada. O objetivo desse estudo foi investigar a resposta celular e humoral em bezerros imunizados com MWNT+rMSP1a, associado com a vacina inativada de A. marginale produzida in vitro, e avaliar os efeitos tóxicos dos MWNT nas funções hepática e renal. rMSP1 a foi ligada covalentemente aos MWNT. Vacina inativada (AmUFMG2) foi produzida através do cultivo de A. marginale em células IDE8. Vinte e quatro bezerros Holandeses foram divididos (quatro grupos) e imunizados subcutaneamente com: PBS e MWNT não-carboxilados (controle, G1), AmUFMG2 (G2), MWNT+rMSP1 a (G3), e AmUFMG2 com MWNT+rMSP1a (G4). Amostras de sangue foram coletadas para contagem de leucócitos, perfil bioquímico e avaliação da resposta celular e humoral. Imunização com MWNT+rMSP1a induziu aumento dos leucócitos totais, células NK, na população de linfócitos e altos níveis de anticorpos comparado com animais imunizados apenas com AmUFMG2. Além disso, MWNT não induziu alterações no perfil bioquímico. Esses dados indicam que MWNT+rMSP1a foram capazes de induzir eficientemente a resposta imune comparado com AmUFMG2 sozinho, sem gerar toxicidade.

Abstract Vaccination against Anaplasma marginale has been considered an important control strategy for bovine anaplasmosis. Recently, mice immunized with rMSP1 a linked to carbon nanotubes (MWNT) showed significant immune responses, generating a new possibility for use of an inactivated vaccine. The objective of this study was to investigate the cellular and humoral responses in calves immunized with MWNT+rMSP1a , associated with inactivated vaccine of A. marginale produced in vitro, and evaluate the toxic effects of the MWNT on renal and hepatic function. rMSP1a was covalently linked to MWNT. Inactivated vaccine (AmUFMG2) was produced by cultivating A. marginale in IDE8 cells. Twenty-four Holstein calves were divided (four groups) and immunized subcutaneously with PBS and non-carboxylated MWNT (control, G1), AmUFMG2 (G2), MWNT+rMSP1a (G3), and AmUFMG2 with MWNT+rMSP1a (G4). Blood samples were collected for total leukocyte counts, biochemical profiling and evaluation of the cellular and humoral response. Immunization with MWNT+rMSP1a induced increase in the total number of leukocytes, NK cells, in the lymphocyte populations and higher levels of antibodies compared to calves immunized only with AmUFMG2. Furthermore, MWNT did not induce changes in the biochemical profile. These data indicate that MWNT+rMSP1a were able to induce the immune responses more efficiently than AmUFMG2 alone, without generating toxicity.

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.

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.

Lectin-carbohydrate binding may be involved in the recognition of Schistosoma mansoni sporocysts by haemocytes of Biomphalaria; therefore, we tested if this interaction is associated with snail resistance against Schistosoma infection. In vitro data showed that most of the S. mansoni sporocysts cultured with haemocytes from Biomphalaria glabrata BH, a highly susceptible snail strain, had a low number of cells that adhered to their tegument and a low mortality rate. Moreover, the addition of N-acetyl-D-glucosamine (GlcNAc) did not alter this pattern of adherence and mortality. Using haemocytes and haemolymph of Biomphalaria tenagophila Cabo Frio, we observed a high percentage of sporocysts with adherent cells, but complete encapsulation was not detected. Low concentrations of GlcNAc increased haemocyte binding to the sporocysts and mortality, which returned to basal levels with high concentrations of the carbohydrate. In contrast, haemocytes plus haemolymph from B. tenagophila Taim encapsulated cellular adhesion index of level 3 and destroyed over 30% of the S. mansoni sporocysts in culture. Interestingly, the addition of GlcNAc, but not mannose, to the culture medium resulted in the significant inhibition of cellular adhesion to the parasite tegument and the reduction of parasite mortality, suggesting that GlcNAc carbohydrate moieties are important to the recognition of S. mansoni by B. tenagophila Taim.

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.

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.

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.