RESUMO
Canine leishmaniasis (CanL) is caused by the intracellular parasite Leishmania infantum. Prostaglandin E2 (PGE2 ) exerts potent regulatory effects on the immune system in experimental model Leishmania infection, but this influence has not yet been studied in CanL. In this study, PGE2 and PGE2 receptor levels and the regulatory effect of PGE2 on arginase activity, NO2 , IL-10, IL-17, IFN-γ, TNF-α and parasite load were evaluated in cultures of splenic leucocytes obtained from dogs with CanL in the presence of agonists and inhibitors. Our results showed that splenic leucocytes from dogs with CanL had lower EP2 receptor levels than those of splenic leucocytes from healthy animals. We observed that NO2 levels decreased when the cells were treated with a PGE2 receptor agonist (EP1/EP2/EP3) or COX-2 inhibitor (NS-398) and that TNF-α, IL-17 and IFN-γ cytokine levels decreased when the cells were treated with a PGE2 receptor agonist (EP2) or PGE2 itself. The parasite load in splenic leucocyte cell cultures from dogs with CanL decreased after stimulation of the cells with PGE2 . We conclude that Leishmania infection of dogs modulates PGE2 receptors and speculate that the binding of PGE2 to its receptors may activate the microbicidal capacity of cells.
Assuntos
Citocinas/imunologia , Dinoprostona/metabolismo , Doenças do Cão/tratamento farmacológico , Leishmania infantum/imunologia , Leishmaniose/veterinária , Receptores de Prostaglandina E/metabolismo , Animais , Anti-Inflamatórios não Esteroides/farmacologia , Inibidores de Ciclo-Oxigenase 2/farmacologia , Dinoprostona/agonistas , Dinoprostona/antagonistas & inibidores , Doenças do Cão/imunologia , Doenças do Cão/parasitologia , Cães , Leishmaniose/tratamento farmacológico , Leishmaniose/imunologia , Óxido Nítrico/análise , Nitrobenzenos/farmacologia , Carga Parasitária , Receptores de Prostaglandina E/agonistas , Receptores de Prostaglandina E/fisiologia , Sulfonamidas/farmacologia , Fator de Necrose Tumoral alfa/imunologiaRESUMO
In this study, we evaluated the performance of a new enzyme-linked immunosorbent assay (ELISA) variant known as indirect "plasmonic ELISA" (pELISA) for the detection of Leishmania spp. infection. Serum samples from 170 dogs from an area where canine leishmaniosis (CanL) is endemic and from 26 healthy dogs from a nonendemic area were tested by indirect pELISA, and the results were compared to those of an indirect ELISA (both with recombinant antigen rK28) and those of an immunochromatographic test (dual-path platform, TR-DPP®) using real-time PCR on blood samples or conjunctival swabs as the gold standard. The pELISA, indirect rK28 ELISA and the TR-DPP® immunochromatographic test presented sensitivities of 94.7%, 89.5% and 79.0% and specificities of 100%, 92.7% and 91.5%, respectively. The analysis of the results revealed that the specificity of the indirect pELISA was greater than that of the method recommended by the Ministry of Health in Brazil and may increase the feasibility of diagnosis in resource-constrained countries because it does not require sophisticated instruments to read. Thus, this method can be used as an additional tool for the detection of Leishmania spp. infection in these areas.
Assuntos
Doenças do Cão/diagnóstico , Ensaio de Imunoadsorção Enzimática/métodos , Leishmaniose/veterinária , Animais , Anticorpos Antiprotozoários/sangue , Antígenos de Protozoários/análise , Brasil , Doenças do Cão/sangue , Cães , Leishmaniose/sangue , Leishmaniose/diagnóstico , Reação em Cadeia da Polimerase em Tempo Real/veterinária , Sensibilidade e Especificidade , Testes Sorológicos/métodosRESUMO
Eosinophils are traditionally associated with the immune response against helminth parasites. However, several studies have demonstrated that these cells have a role regarding protective immunity in leishmaniasis. Here, we examined the relationship between the presence of eosinophils and parasite load in biopsy samples from dogs, obtained through fine needle puncture and aspiration of lymph nodes. Histological slides containing biopsy material from lymph nodes of dogs with canine visceral leishmaniasis and healthy dogs were used to obtain baseline eosinophil counts. Subsequently, scrapings were taken from slides for DNA extraction and determination of parasite load, using real-time PCR (qRT-PCR). Additionally, production of nitric oxide (NO) and reactive oxygen species (ROS) levels by eosinophils in the peripheral blood of dogs with canine visceral leishmaniasis and healthy dogs was measured. The eosinophil percentage were higher in lymph nodes of infected group, and the parasite load showed a significant negative correlation with the eosinophil count. The production of NO and ROS by eosinophils in the peripheral blood was higher in the dogs with canine visceral leishmaniasis. All the results together suggest that eosinophils may participate in antileishmanial immunity in canine visceral leishmaniasis.
Assuntos
Anti-Helmínticos/imunologia , Doenças do Cão/imunologia , Leishmaniose Visceral/veterinária , Óxido Nítrico/metabolismo , Espécies Reativas de Oxigênio/metabolismo , Animais , Doenças do Cão/parasitologia , Cães , Eosinófilos/imunologia , Feminino , Inflamação/patologia , Inflamação/veterinária , Leishmania infantum/imunologia , Leishmaniose Visceral/imunologia , Leishmaniose Visceral/parasitologia , Linfonodos/imunologia , Linfonodos/parasitologia , Carga Parasitária/veterinária , Reação em Cadeia da Polimerase em Tempo Real/veterináriaRESUMO
Sand flies are recognized as the major vector of canine visceral leishmaniasis. However, in some areas of Brazil where sand flies do not occur, this disease is found in humans and dogs. There has been speculation that ticks might play a role in transmission of canine visceral leishmaniasis and the DNA of Leishmania spp. has been reported in whole ticks. We investigated the presence of Leishmania spp. promastigotes in the intestines, ovaries, and salivary glands of Rhipicephalus sanguineus ticks collected from tick-infested dogs in two cities of Brazil. We used 66 dogs that tested positive and 33 that tested negative for Leishmania spp. according to direct cytological examination assays. Ten ticks were collected from each dog and dissected to collect the intestines, ovaries, and salivary glands for immunohistochemistry (IHC) and diagnostic real-time polymerase chain reaction (RT-PCR). IHC results showed Leishmania spp. in 98, 14, and 8 % of the intestines, ovaries, and salivary glands, respectively. Real-time PCR showed that 89, 41, and 33 % of the tick intestine, ovary, and salivary glands, respectively, were positive for Leishmania spp. The verification of promastigotes of Leishmania spp. by two independent techniques in ticks collected from these urban region dogs showed that there is need for clarification of the role of ticks in the transmission of canine visceral leishmaniasis in Brazil.
Assuntos
Doenças do Cão/parasitologia , Intestinos/parasitologia , Leishmania/classificação , Leishmaniose Visceral/veterinária , Ovário/parasitologia , Rhipicephalus sanguineus/parasitologia , Glândulas Salivares/parasitologia , Animais , Brasil , Doenças do Cão/diagnóstico , Cães , Feminino , Humanos , Leishmania/isolamento & purificação , Leishmaniose Visceral/parasitologia , Leishmaniose Visceral/transmissão , Masculino , Psychodidae/parasitologia , Reação em Cadeia da Polimerase em Tempo Real , Infestações por Carrapato/veterináriaRESUMO
OBJECTIVES: This study aimed to evaluate the influence of apical periodontitis (AP) and/or periodontal disease (PD) on serum interleukin-17 (IL-17) levels in a rat model of diabetes mellitus (DM). METHODS: Eighty male Wistar rats were divided into eight groups of ten animals each: normoglycemic, AP, PD, AP+PD, DM, DM+AP, DM+PD, and DM+AP+PD. DM was induced using streptozotocin, AP by dental pulp exposure to the oral environment, and PD by periodontal ligature. The animals were sacrificed after 30 days, and venous blood samples were collected via cardiac puncture to determine the serum IL-17 and neutrophil levels. The maxillae were dissected and processed for radiographic analysis. The periapical lesion areas were quantified in pixels. The total assessed values were tabulated according to each experimental group and were statistically analyzed using Spearman's correlation and Kruskal-Wallis test (p < 0.05). RESULTS: A significant difference in the serum IL-17 levels was observed between the groups without oral infections and the groups with AP+PD-associated lesions, regardless of the presence of DM (p < 0.05). Diabetes increased the neutrophil levels, regardless of the presence of oral infection. However, a combination of two oral infections increased the neutrophil levels in DM rats (p < 0.05). The level of bone resorption lesions was greater in DM rats than in normoglycemic rats (p < 0.05). CONCLUSION: The combination of AP and PD increased the serum IL-17 levels in DM and normoglycemic rats and increased the neutrophil levels in DM rats. Diabetes increased the neutrophil levels and bone resorption in rats. CLINICAL SIGNIFICANCE: AP is capable of potentiating systemic inflammatory changes when associated with PD, and increases in blood glucose can accelerate the pathogenesis of oral infections.
Assuntos
Diabetes Mellitus Experimental/sangue , Interleucina-17/sangue , Doenças Periodontais/sangue , Animais , Masculino , Neutrófilos , Periodontite Periapical/sangue , Periodontite Periapical/diagnóstico por imagem , Doenças Periodontais/diagnóstico por imagem , Radiografia , Ratos , Ratos Wistar , EstreptozocinaRESUMO
Domestic dogs are the primary urban reservoirs of Leishmania infantum, the causative agent of visceral leishmaniasis. In Canine Leishmaniasis (CanL), modulation of the host's immune response may be associated with the expression of small non-coding RNAs called microRNA (miR). miR-194 expression increases in peripheral blood mononuclear cells (PBMCs) of dogs with leishmaniasis with a positive correlation with the parasite load and in silico analysis demonstrated that the TRAF6 gene is the target of miR-194 in PBMCs from diseased dogs. Here, we isolated PBMCs from 5 healthy dogs and 28 dogs with leishmaniasis, naturally infected with L. infantum. To confirm changes in miR-194 and TRAF6 expression, basal expression of miR-194 and gene expression of TRAF6 was measured using qPCR. PBMCs from healthy dogs and dogs with leishmaniasis were transfected with miR-194 scramble, mimic, and inhibitor and cultured at 37° C, 5% CO2 for 48 hours. The expression of possible targets was measured: iNOS, NO, T-bet, GATA3, and FoxP3 were measured using flow cytometry; the production of cytokines IL-1ß, IL-4, IL-6, IL-10, TNF-α, IFN-γ, and TGF-ß in cell culture supernatants was measured using capture enzyme-linked immunosorbent assays (ELISA). Parasite load was measured using cytometry and qPCR. Functional assays followed by miR-194 inhibitor and IL-1ß blockade and assessment of NO production were also performed. Basal miR-194 expression was increased in PBMC from dogs with Leishmaniasis and was negatively correlated with TRAF6 expression. The mimic of miR-194 promoted an increase in parasite load. There were no significant changes in T-bet, GATA3, or FoxP3 expression with miR-194 enhancement or inhibition. Inhibition of miR-194 increased IL-1ß and NO in PBMCs from diseased dogs, and blockade of IL-1ß following miR-194 inhibition decreased NO levels. These findings suggest that miR-194 is upregulated in PBMCs from dogs with leishmaniasis and increases parasite load, possibly decreasing NO production via IL-1ß. These results increase our understanding of the mechanisms of evasion of the immune response by the parasite and the identification of possible therapeutic targets.
Assuntos
Doenças do Cão , Leishmania infantum , Leishmaniose Visceral , Leishmaniose , MicroRNAs , Animais , Cães , Citocinas/genética , Doenças do Cão/parasitologia , Fatores de Transcrição Forkhead , Leishmania infantum/fisiologia , Leishmaniose Visceral/genética , Leishmaniose Visceral/veterinária , Leucócitos Mononucleares , MicroRNAs/genética , Óxido Nítrico/metabolismo , Carga Parasitária , Fator 6 Associado a Receptor de TNF , Leishmaniose/veterinária , Interleucina-1beta/metabolismoRESUMO
Leishmania infantum causes visceral leishmaniosis, a neglected tropical disease that can modulate the host immune response by altering the expression of small non-coding RNAs called microRNAs (miRNAs). Some miRNAs are differentially expressed in peripheral blood mononuclear cells (PBMCs) of dogs with canine visceral leishmaniosis (CanL), like the down-regulated miR-150. Even though miR-150 is negatively correlated with L. infantum parasitic load, it is unclear if miR-150 directly affects L. infantum parasitic load and (if so) how this miRNA would contribute to infection. Here, we isolated PBMCs from 14 naturally infected dogs (CanL group) and six healthy dogs (Control group) and treated them in vitro with miR-150 mimic or inhibitor. We measured L. infantum parasitic load using qPCR and compared treatments. We also measured miR-150 in silico predicted target protein levels (STAT1, TNF-α, HDAC8, and GZMB) using flow cytometry or enzyme-linked immunosorbent assays. Increasing miR-150 activity diminished L. infantum parasitic load in CanL PBMCs. We also found that inhibition of miR-150 reduced GZMB (granzyme B) levels. These findings demonstrate that miR-150 plays an important role in L. infantum infection in canine PBMCs, and they merit further studies aiming at drug development.
Assuntos
Doenças do Cão , Leishmania infantum , Leishmaniose Visceral , MicroRNAs , Animais , Cães , Leucócitos Mononucleares , Granzimas , Leishmaniose Visceral/parasitologia , Leishmaniose Visceral/veterinária , MicroRNAs/genética , Doenças do Cão/parasitologiaRESUMO
Canine leishmaniasis (CanL) is a severe public health threat. Infected animals mediate transmission of the Leishmania protozoan to humans via the sandfly's bite during a blood meal. CanL progression depends on the degree of suppression of the immune response, possibly associated with microRNAs (miR), which can modulate mRNA translation into proteins and (consequently) regulate cell function. Increased miR-148a in splenic leukocytes (SL) of dogs with CanL was observed in previous studies, and in silico analysis, identified possible pathways involved in immune response regulation that are affected by this miR. Therefore, we evaluated the involvement of miR-148a in the regulation of TNF-α, IL-6, IL-12, IL-1ß, iNOS, MHCII, CD80, CD3, T-bet, and GATA-3 transcription factors and their relationship with parasite load in SL of dogs with CanL. Splenic leukocytes obtained from healthy and diseased dogs were transfected with miR-148a mimic and inhibitor oligonucleotides. After 48 hours, expression levels of MHCII, CD80, iNOS, CD3, T-bet, and GATA-3 were evaluated by flow cytometry, and concentrations of TNF-α, IL-12, IL-6, and IL-1ß were measured in culture supernatants by capture enzyme-linked immunosorbent assays. Transfection of SL with miR-148a mimics decreased iNOS levels in cells and TNF-α, IL-6, and IL-12 in the supernatants of cultured SL from CanL dogs. Interestingly, transfection with miR-148a inhibitor decreased parasite load in SL cells. These results suggest a direct or not regulatory role of this miR in the immune response to Leishmania infantum infection. We conclude that miR-148a can modulate immune responses by regulating inflammatory cytokines during CanL. Our results contribute to understanding the complex host/parasite interaction in CanL and could assist the development of treatments.
Assuntos
Doenças do Cão , Leishmania infantum , Leishmaniose Visceral , Leishmaniose , MicroRNAs , Animais , Cães , Citocinas , Doenças do Cão/parasitologia , Interleucina-12/genética , Interleucina-6 , Leishmania infantum/genética , Leishmaniose/veterinária , Leishmaniose Visceral/parasitologia , MicroRNAs/genética , Carga Parasitária , Fator de Necrose Tumoral alfa/genéticaRESUMO
Canine Visceral leishmaniasis (CanL) poses a severe public health threat in several countries. Disease progression depends on the degree of immune response suppression. MicroRNAs (miRs) modulate mRNA translation into proteins and regulate various cellular functions and pathways associated with immune responses. MiR-21 and miR-148a can alter the parasite load and M1 macrophages are the principal cells in dogs' leishmanicidal activity. A previous study found increased miR-21 and miR-148a in splenic leukocytes (SL) of dogs with CanL using microarray analysis and in silico analysis identified PTEN pathway targets. PTEN is involved in the immune regulation of macrophages. We measured PTEN and the production of reactive oxygen species (ROS) and nitric oxide (NO) before and after transfection SLs of dogs with CanL with mimic and inhibition of miR-21 and miR-148a. PTEN levels increased, NO and ROS decreased in SLs from dogs with CanL. Inhibition of miRNA-21 resulted in PTEN increase; in contrast, PTEN decreased after miR-148a inhibition. Nitrite (NO2) levels increased after transfection with miR-21 inhibitor but were decreased with miR-148a inhibitor. The increase in miR-21 promoted a reduction in ROS and NO levels, but miR-148a inhibition increased NO and reduced ROS. These findings suggest that miR-21 and miR-148a can participate in immune response in CanL, affecting PTEN, NO, and ROS levels.
RESUMO
Dogs are considered the major domestic reservoir for human visceral leishmaniasis, a serious disease caused by the Leishmania infantum parasite. Diagnosis of canine visceral leishmaniasis (CVL) is critical for disease control, with several methods currently available. Among the serological tests, the DPP rapid test and the EIE-LVC, more commonly used in Brazil, are associated with variable sensitivity and specificity. Research with novel recombinant proteins such as the ELISA with the recombinant chimeric protein Q5 may therefore improve the CVL diagnosis. This study aimed to evaluate the true diagnostic potential of Q5 in an ELISA assay using a large number of CVL-suspected sera (406) with a previous positive diagnosis based on the rapid DPP test. Sera from the DPP-positive dogs, also assessed with the EIE-LVC test, were compared with sera from healthy dogs (n = 46) and used for ELISA tests using the recombinant Q5. The resulting data as well as the correlation with the clinical signs and the environmental characteristics of the animals were analyzed using Medal and GraphPad Prism 8.0. Overall, similar levels of lower sensitivity (67-68%) were seen for both the commercial EIE-LVC test and the Q5 ELISA when all assessed sera were considered, but a much greater sensitivity (92%) was seen for those samples from symptomatic dogs only. In contrast, many negative results were observed for the DPP-positive sera from asymptomatic dogs or those with no clinical information available. A selection of those sera were tested yet again in new ELISA assays using a second batch of the recombinant Q5, purified under milder denaturing conditions, as well as using another recombinant protein (Lci13). The results reveal a higher-than-expected incidence of likely false-positive results for DPP, reinforcing the need for other recombinant proteins, such as the chimeric Q5, to be investigated as possible alternatives to the currently used CVL diagnostic methods.
RESUMO
We investigated the zoonotic transmission of Cryptosporidium among the children (n = 188), dogs (n = 133), and cats (n = 55) living in 188 households. Fecal samples were examined using ELISA and confirmed via nested PCR. Coproantigens oocysts were detected in 3.7% of children, 8.3% of dogs, and 5.5% of cats. We found strong evidence of two cases of the zoonotic transmission of Cryptosporidium canis between children and dogs. Furthermore, four children and their respective pets (one dog and three cats) were infected with Cryptosporidium parvum, but we cannot exclude the hypotheses that the oocysts were transmitted from children to animals or that both hosts were infected by a shared source, such as contaminated water or food. The presence of an infected animal elevated the risk of zoonotic transmission by 129.7-fold (95% CI: 13.92-1209.68). Furthermore, sharing a bed with pets was identified as a risk factor for infection in children (OR: 9.9, 95% CI: 1.37-71.2). In conclusion, the zoonotic transmission of Cryptosporidium among children and pets cohabiting in the same household may be quite common, especially when infected animals lie or sleep on children's beds. These findings unequivocally highlight the public health concern surrounding C. canis.
RESUMO
Visceral leishmaniasis in humans is a chronic and fatal disease if left untreated. Canine leishmaniasis (CanL) is a severe public health problem because infected animals are powerful transmitters of the parasite to humans via phlebotomine vectors. Therefore, dogs are an essential target for control measures. Progression of canine infection is accompanied by failure of cellular immunity with reduction of circulating lymphocytes and increased cytokines that suppress macrophage function. Studies showed that the regulation of the effector function of macrophages and T cells appears to depend on miRNAs; miRNA-21 (miR-21) shows increased expression in splenic leukocytes of dogs with CanL and targets genes related to the immune response. Mimics and inhibitors of miR-21 were used in vitro to transfect splenic leukocytes from dogs with CanL. After transfection, expression levels of the proteins FAS, FASL, CD69, CCR7, TNF-α, IL-17, IFN-γ, and IL-10 were measured. FAS, FASL, CD69, and CCR7 expression levels decreased in splenic leukocytes from dogs with CanL. The miR-21 mimic decreased CD69 expression in splenic leukocytes from CanL and healthy groups. The miR-21 inhibitor decreased IL-10 levels in culture supernatants from splenic leukocytes in the CanL group. These findings suggest that miR-21 alters the immune response in CanL; therefore, miR-21 could be used as a possible therapeutic target for CanL.
Assuntos
Doenças do Cão , Leishmania infantum , Leishmaniose Visceral , Leishmaniose , MicroRNAs , Animais , Doenças do Cão/parasitologia , Cães , Interleucina-10/genética , Interleucina-10/uso terapêutico , Leishmaniose/veterinária , Leishmaniose Visceral/tratamento farmacológico , Leishmaniose Visceral/genética , Leishmaniose Visceral/veterinária , MicroRNAs/genética , MicroRNAs/uso terapêutico , Receptores CCR7RESUMO
The seroprevalence of infection by Toxoplasma gondii, Neospora caninum, and Leishmania spp. was detected through an indirect immunofluorescence in 70 cats from the Andradina Municipality, São Paulo State, Brazil. Anti-T. gondii antibodies (titer >64) were detected in 15.7% (11/70) of animals, whereas positivity for N. caninum (titer 16) was not observed in any animal. Of the cats from urban and rural areas, 10.4% (5/48) and 27.2% (6/22) were positive for T. gondii, respectively. Breed, age, food, and contact with animals of other species were significant for considering the positivity for T. gondii (P ≤ 0.0001). Cats having access to streets (17.1%, 11/64), cats cohabiting with rats (19.6%, 10/51), and cats feeding on homemade food and raw milk (27.2%, 6/22) were positive for T. gondii. In addition, 4.2% (3/70) of the cats were positive for Leishmania spp. by ELISA technique and negative by IFAT without coinfection with T. gondii and Leishmania spp. There was no serological positivity against feline immunodeficiency virus or feline leukemia virus. In conclusion, T. gondii infection in part of the feline population from Andradina is not linked to immunosuppressions or coinfections but probably to postnatal infection in association with the type of diet and presence of rats.
Assuntos
Anticorpos Antiprotozoários/análise , Doenças do Gato/epidemiologia , Leishmania/imunologia , Leishmaniose/epidemiologia , Toxoplasma/imunologia , Toxoplasmose Animal/epidemiologia , Animais , Anticorpos Antiprotozoários/imunologia , Brasil , Doenças do Gato/imunologia , Doenças do Gato/parasitologia , Gatos , Coccidiose/epidemiologia , Coccidiose/imunologia , Coccidiose/parasitologia , Coccidiose/veterinária , Ecossistema , Ensaio de Imunoadsorção Enzimática/veterinária , Comportamento Alimentar , Feminino , Técnica Indireta de Fluorescência para Anticorpo/veterinária , Leishmaniose/imunologia , Leishmaniose/parasitologia , Leishmaniose/veterinária , Masculino , Neospora/imunologia , Ratos , Fatores de Risco , Estudos Soroepidemiológicos , Testes Sorológicos , Toxoplasmose Animal/imunologia , Toxoplasmose Animal/parasitologiaRESUMO
rIL-10 plays a major role in restricting exaggerated inflammatory and immune responses, thus preventing tissue damage. However, the restriction of inflammatory and immune responses by IL-10 can also favor the development and/or persistence of chronic infections or neoplasms. Dogs that succumb to canine leishmaniasis (CanL) caused by L. infantum develop exhaustion of T lymphocytes and are unable to mount appropriate cellular immune responses to control the infection. These animals fail to mount specific lymphoproliferative responses and produce interferon gamma and TNF-alpha that would activate macrophages and promote destruction of intracellular parasites. Blocking IL-10 signaling may contribute to the treatment of CanL. In order to obtain a tool for this blockage, the present work endeavored to identify the canine casIL-10R1 amino acid sequence, generate a recombinant baculovirus chromosome encoding this molecule, which was expressed in insect cells and subsequently purified to obtain rcasIL-10R1. In addition, rcasIL-10R1 was able to bind to homologous IL-10 and block IL-10 signaling pathway, as well as to promote lymphoproliferation in dogs with leishmaniasis caused by L. infantum.
Assuntos
Interleucina-10/metabolismo , Leishmaniose/tratamento farmacológico , Receptores de Interleucina-10/metabolismo , Animais , Linhagem Celular , Citocinas/metabolismo , Doenças do Cão/genética , Cães , Feminino , Imunidade Celular/imunologia , Imunidade Celular/fisiologia , Interferon gama/genética , Interleucina-10/agonistas , Interleucina-12/genética , Leishmania infantum/imunologia , Leishmania infantum/patogenicidade , Leishmaniose/imunologia , Macrófagos/metabolismo , Masculino , Camundongos , Receptores de Interleucina-10/efeitos dos fármacos , Transdução de Sinais , Linfócitos T/imunologia , Fator de Necrose Tumoral alfaRESUMO
Leishmaniasis is an immunosuppressive disease caused by protozoa of the genus Leishmania, for which dogs are the domestic reservoir. The programmed cell death-1 molecule (PD-1) is highly expressed in leukocyte cells of dogs with leishmaniasis, and it promotes T lymphocyte exhaustion and suppression of cytokine secretion. Because PD-1 has a suppressive function regarding cell immunity, we evaluated the effect of PD-1 blocking antibodies on NO, ROS and interleukin 17 (IL-17) production and on parasite load in spleen leukocyte cultures from dogs with leishmaniasis. In vitro, PD-1 blocking promoted increased levels of intracellular NO and NO2 and reduced the levels of IL-17 in the culture supernatant, in addition to reducing the parasite load, but it did not change ROS levels. We conclude that PD-1 participates in the regulation of the immune response and that the blocking antibody is effective in restoring host microbicidal activity. This can be investigated in an immunotherapeutic study in the future.
Assuntos
Anticorpos Monoclonais/imunologia , Doenças do Cão/imunologia , Regulação da Expressão Gênica/imunologia , Interleucina-17/imunologia , Leishmaniose Visceral/veterinária , Receptor de Morte Celular Programada 1/imunologia , Animais , Técnicas de Cultura de Células , Meios de Cultura/química , Doenças do Cão/parasitologia , Cães , Feminino , Leishmania infantum , Leishmaniose Visceral/imunologia , Leucócitos/efeitos dos fármacos , Leucócitos/imunologia , Masculino , Óxido Nítrico/análise , Dióxido de Nitrogênio/análise , Carga Parasitária , Receptor de Morte Celular Programada 1/antagonistas & inibidores , Espécies Reativas de Oxigênio/análise , Baço/imunologiaRESUMO
PD-1 is a negative costimulator of chronic infectious diseases In this study, we investigated the expression of PD-1 and its ligands in the spleen of dogs with visceral leishmaniasis and lymphoproliferative response to soluble antigen, in lymph node cells in the presence or absence of antibodies blocking PD-1 and its ligands. Our results showed expression of PD-1 and its ligands is higher after L. infantum infection and in the spleen of infected dogs, PD-1 blockage was able to restore the antigen-dependent lymphoproliferative response and regulated production of the cytokines IL-4 and IL-10 and NO production. We concluded that L. infantum infection modulates PD-1 and its ligands expression in canine VL and that blockage of PD-1 restores the immune response. Thus, blockage of PD-1 is a target for therapeutic drug development.
Assuntos
Antígeno B7-H1/metabolismo , Doenças do Cão/imunologia , Doenças do Cão/metabolismo , Imunidade Celular , Leishmaniose Visceral/veterinária , Receptor de Morte Celular Programada 1/metabolismo , Animais , Antígeno B7-H1/genética , Citocinas/metabolismo , Doenças do Cão/parasitologia , Cães , Feminino , Expressão Gênica , Imuno-Histoquímica , Imunofenotipagem , Leucócitos/imunologia , Leucócitos/metabolismo , Linfócitos/imunologia , Linfócitos/metabolismo , Macrófagos/imunologia , Macrófagos/metabolismo , Masculino , Carga Parasitária , Receptor de Morte Celular Programada 1/genética , Baço/imunologia , Baço/metabolismoRESUMO
Visceral Leishmaniasis is a chronic zoonosis and, if left untreated, can be fatal. Infected dogs have decreased cellular immunity (Th1) and develop a potent humoral response (Th2), which is not effective for elimination of the protozoan. Immune response can be modulated by microRNAs (miRNAs), however, characterization of miRNAs and their possible regulatory role in the spleen of infected dogs have not been done. We evaluated miRNA expression in splenic leukocytes (SL) from dogs naturally infected with Leishmania infantum and developing leishmaniasis (CanL; n = 8) compared to healthy dogs (n = 4). Microarray analysis showed increased expression of miR 21, miR 148a, miR 7 and miR 615, and downregulation of miR 150, miR 125a and miR 125b. Real-time PCR validated the differential expression of miR 21, miR 148a and miR 615. Further, decrease of miR 21 in SL, by means of transfection with a miR 21 inhibitor, increased the IL-12 cytokine and the T-bet/GATA-3 ratio, and decreased parasite load on SL of dogs with CanL. Taken together, these findings suggest that L. infantum infection alters splenic expression of miRNAs and that miR 21 interferes in the cellular immune response of L. infantum-infected dogs, placing this miRNA as a possible therapeutic target in CanL.
Assuntos
Doenças do Cão/diagnóstico , Interleucina-12/metabolismo , Leishmaniose Visceral/diagnóstico , Leucócitos/metabolismo , MicroRNAs/metabolismo , Baço/metabolismo , Animais , Antagomirs/metabolismo , Anticorpos Monoclonais/imunologia , Doenças do Cão/imunologia , Doenças do Cão/parasitologia , Cães , Regulação para Baixo , Fator de Transcrição GATA3/metabolismo , Imunidade Celular , Interleucina-12/antagonistas & inibidores , Leishmania infantum/imunologia , Leishmania infantum/fisiologia , Leishmaniose Visceral/imunologia , Leishmaniose Visceral/parasitologia , Leucócitos/citologia , MicroRNAs/antagonistas & inibidores , MicroRNAs/genética , Baço/imunologia , Proteínas com Domínio T/metabolismo , Células Th1/citologia , Células Th1/imunologia , Células Th1/metabolismo , Células Th2/citologia , Células Th2/imunologia , Células Th2/metabolismo , Regulação para CimaRESUMO
This study evaluated the performance of crude total antigen (CTA) and fucose-mannose ligand antigen (FML) in an enzyme-linked immunosorbent assay for diagnosis of canine visceral leishmaniasis (CVL). The assays used sera from known negative controls (n=30), clinically symptomatic (n=30) and oligosymptomatic (n=30) parasitologically proven infection (by microscopy). Aspirates of popliteal lymph node from infected canines were colleted to score parasitism and compared with the ELISA results. The study indicated that FML used in ELISA provided high sensitivity for detecting oligosymptomatic dogs (90%) and CTA showed greater sensitivity than FML for symptomatic canines (90%). In oligosymptomatic dogs, specificity was 100% for CTA-ELISA, but in symptomatic dogs, FML specificity was higher (96.7%) than CTA-ELISA (93.3%). A significant correlation was observed between the degree of parasitism and the results obtained in CTA-ELISA. Since no available antigen offers 100% specificity and sensitivity for CVL diagnosis, the choice of antigen used must depend on the aim of the investigation.
Assuntos
Antígenos de Protozoários/imunologia , Doenças do Cão/diagnóstico , Ensaio de Imunoadsorção Enzimática/veterinária , Leishmaniose Visceral/veterinária , Animais , Antígenos de Protozoários/sangue , Cães , Ensaio de Imunoadsorção Enzimática/métodos , Leishmaniose Visceral/diagnóstico , Linfonodos/parasitologia , Sensibilidade e EspecificidadeRESUMO
This paper contains data on differentially expressed miRNAs in peripheral blood mononuclear cells (PBMC) of dogs naturally infected by Leishmania (L.) infantum compared to healthy dogs. In recent years, studies with miRNAs have shown that these molecules play a critical role in the regulation and function of immune response.Differentially expressed miRNAs were identified by microarray, validated by real time PCR and compared with parasite load in the dogs. Targets and pathways were analyzed using the Ingenuity Pathway Analysis program.
RESUMO
Visceral leishmaniasis (VL) in humans is a chronic and often fatal disease if left untreated. Dogs appear to be the main reservoir host for L. infantum infection, however, in many regions other canids such as jackals, foxes, wolves and other mammals, such as hares or black rats, have been implicated as wild reservoirs. Most dogs cannot form an effective immune response against this infection, and this could be modulated by small non-coding RNAs, called microRNAs, responsible for post-transcriptional control of gene expression. Here, we evaluated the expression of miRNAs in peripheral blood mononuclear cells (PBMC) of symptomatic dogs naturally infected with Leishmania (L.) infantum (n = 10) and compared to those of healthy dogs (n = 5). Microarray analysis revealed that miR-21, miR-424, miR-194 and miR-451 had a 3-fold increase in expression, miR-192, miR-503, and miR-371 had a 2-fold increase in expression, whereas a 2-fold reduction in expression was observed for miR-150 and miR-574. Real-time PCR validated the differential expression of miR-21, miR-150, miR-451, miR-192, miR-194, and miR-371. Parasite load of PBMC was measured by real-time PCR and correlated to the differentially expressed miRNAs, showing a strong positive correlation with expression of miR-194, a regular positive correlation with miR-371 expression, and a moderate negative correlation with miR-150 expression in PBMC. These findings suggest that Leishmania infection interferes with miRNAs expression in PBMC, and their correlation with parasite load may help in the identification of therapeutic targets in Canine Visceral Leishmaniasis (CVL).