Effect of Triatoma infestans saliva on mouse immune system cells: The role of the pore-forming salivary protein trialysin.

Triatoma infestans is one of the most important vectors of Trypanosoma cruzi in the Americas. While feeding, they release large amounts of saliva that will counteract the host's responses triggered at the bite site. Despite the various activities described on T. infestans saliva, little is known about its effect on the modulation of the host's immune system. This work aimed to describe the effects of T. infestans saliva on cells of the mouse immune system and access the role in hematophagy. The effect of saliva or salivary gland extract (SGE) was evaluated in vivo and in vitro by direct T. infestans feeding on mice or using different biological assays. Mice that were submitted to four bites by three specimens of T. infestans had their anti-saliva IgG serum levels approximately 2.4 times higher than controls, but no change in serum IL-2, IL-4, IL-6, IL-10, IL-17A, IFN-γ, and TNF-α levels was observed. No macroscopic alterations were seen at the bite site, but an accumulation of mononuclear and polymorphonuclear cells shortly after the bite and 24 h later were observed in histological cuts. At low concentrations (up to ∼5 µg/well), SGE induced TNF-α production by macrophages and spleen cells, IFN-γ and IL-10 by spleen cells and NO by macrophages. However, at higher concentrations (10 and 20 µg/well), viability of macrophages and spleen cells was reduced by SGE, reducing the production of NO and cytokines (except TNF-α). The salivary trialysin was the main inducer of cell death as macrophage viability and NO production was restored in assays carried out with SGE from trialysin knockdown insects. The reduction of the salivary trialysin by RNAi affected the total ingestion rate, the weight gain, and retarded the molt from second to the fifth instar of T. infestans nymphs fed on mice. The results show that T. infestans saliva modulates the activity of cells of the host immune system and trialysin is an important salivary molecule that reduces host cells viability and impacts the feeding performance of T. infestans feeding on live hosts.

Aspectos clínicos da intoxicação experimental pelas favas de Stryphnodendron fissuratum (Leg. Mimosoideae) em caprinos / Clinical aspects of the experimental poisoning by the pods of Stryphnodendron fissuratum (Leg. Mimosoideae) in goats

Com o objetivo de caracterizar o quadro clínico da intoxicação por Stryphnodendron fissuratum Mart. (Leg. Mimosoideae) em caprinos, administraram-se as favas dessa planta a oito caprinos, por via oral forçada em doses únicas e a outros dois caprinos, em doses fracionadas. A menor dose que causou sinais clínicos e morte foi a de 10g/kg. Doses de 20g/kg e 40g/kg causaram sinais acentuados e doses únicas de 5g/kg não provocaram sinais. Doses fracionadas de 5g/kg durante quatro dias, totalizando 20g/kg provocaram sinais acentuados e morte. Em ambos os grupos, os primeiros sinais de intoxicação foram observados a partir do primeiro dia de experimento e a evolução variou de 4-25 dias. A doença caracterizou-se principalmente por alterações digestórias e nervosas que consistiram em anorexia, desidratação, hipomotilidade e atonia ruminal, timpanismo, gemidos constantes, dor à percussão abdominal, fezes com muco, ranger de dentes, apatia, ataxia, dismetria, tremores de cabeça, tremores musculares, fraqueza com o andar cambaleante e trôpego, acentuada depressão e decúbito esternal ou lateral prolongado e morte. Alguns animais apresentaram acentuada queda de pêlos na região dorsal; apenas um caprino apresentou fezes líquidas, marrom-escuras e fétidas. Outros sinais incluíram perda de fluido ruminal durante a ruminação, sialorréia, exsudato nasal seroso e lacrimejamento. As provas de função hepática e renal revelaram alterações discretas. As concentrações séricas de aspartato aminotransferase encontraram-se levemente aumentadas e as de creatinofosfocinase muito aumentadas.

In order to confirm the susceptibility of goats to the poisoning by Stryphnodendron fissuratum Mart. (Leg. Mimosoideae) and to characterize the clinical disease, the pods of the plant were given orally to each of eight young goats and in fractioned doses to other two. The lowest lethal dose was 10g/kg. The same dose was the lowest that induced disease. Doses of 20g/kg and 40g/kg caused pronounced clinical signs and doses of 5g/kg did not caused signs. Fractioned doses of 5g/kg during four days also caused pronounced signs. In each groups the first signs of poisoning were observed from the first day of experiments and the changes ranged from 4-25 days. The disease was characterized mainly by digestive and nervous disorders. Clinical signs were partial to complete anorexia, dehydration, decrease in ruminal activity up to atonia, tympanism, constant vocalizations, grinding of the teeth pain up on abdominal palpation, apathy, ataxia, depression, dysmetria, head and muscle tremors, weakness, difficulty in rising, sternal or lateral recumbency and death. Some goats presented extense hair loss in the skin of the dorsum; one goat presented liquid and black fetid feces. Other signs included loss of ruminal fluid during rumination, drooling, serous nasal and ocular discharges. Liver and kidney function tests had resulted in slight changes. AST serum levels were slightly increased and creatine phosphokinase levels were highly increased. These changes can associated to the effects of triterpenic saponins contained in the S. fissuratum pods.

Aspectos clínicos da intoxicação experimental pelas favas de Stryphnodendron fissuratum (Leg. Mimosoideae) em caprinos / Clinical aspects of the experimental poisoning by the pods of Stryphnodendron fissuratum (Leg. Mimosoideae) in goats

Com o objetivo de caracterizar o quadro clínico da intoxicação por Stryphnodendron fissuratum Mart. (Leg. Mimosoideae) em caprinos, administraram-se as favas dessa planta a oito caprinos, por via oral forçada em doses únicas e a outros dois caprinos, em doses fracionadas. A menor dose que causou sinais clínicos e morte foi a de 10g/kg. Doses de 20g/kg e 40g/kg causaram sinais acentuados e doses únicas de 5g/kg não provocaram sinais. Doses fracionadas de 5g/kg durante quatro dias, totalizando 20g/kg provocaram sinais acentuados e morte. Em ambos os grupos, os primeiros sinais de intoxicação foram observados a partir do primeiro dia de experimento e a evolução variou de 4-25 dias. A doença caracterizou-se principalmente por alterações digestórias e nervosas que consistiram em anorexia, desidratação, hipomotilidade e atonia ruminal, timpanismo, gemidos constantes, dor à percussão abdominal, fezes com muco, ranger de dentes, apatia, ataxia, dismetria, tremores de cabeça, tremores musculares, fraqueza com o andar cambaleante e trôpego, acentuada depressão e decúbito esternal ou lateral prolongado e morte. Alguns animais apresentaram acentuada queda de pêlos na região dorsal; apenas um caprino apresentou fezes líquidas, marrom-escuras e fétidas. Outros sinais incluíram perda de fluido ruminal durante a ruminação, sialorréia, exsudato nasal seroso e lacrimejamento. As provas de função hepática e renal revelaram alterações discretas. As concentrações séricas de aspartato aminotransferase encontraram-se levemente aumentadas e as de creatinofosfocinase muito aumentadas.

In order to confirm the susceptibility of goats to the poisoning by Stryphnodendron fissuratum Mart. (Leg. Mimosoideae) and to characterize the clinical disease, the pods of the plant were given orally to each of eight young goats and in fractioned doses to other two. The lowest lethal dose was 10g/kg. The same dose was the lowest that induced disease. Doses of 20g/kg and 40g/kg caused pronounced clinical signs and doses of 5g/kg did not caused signs. Fractioned doses of 5g/kg during four days also caused pronounced signs. In each groups the first signs of poisoning were observed from the first day of experiments and the changes ranged from 4-25 days. The disease was characterized mainly by digestive and nervous disorders. Clinical signs were partial to complete anorexia, dehydration, decrease in ruminal activity up to atonia, tympanism, constant vocalizations, grinding of the teeth pain up on abdominal palpation, apathy, ataxia, depression, dysmetria, head and muscle tremors, weakness, difficulty in rising, sternal or lateral recumbency and death. Some goats presented extense hair loss in the skin of the dorsum; one goat presented liquid and black fetid feces. Other signs included loss of ruminal fluid during rumination, drooling, serous nasal and ocular discharges. Liver and kidney function tests had resulted in slight changes. AST serum levels were slightly increased and creatine phosphokinase levels were highly increased. These changes can associated to the effects of triterpenic saponins contained in the S. fissuratum pods.