RESUMO
IL-23 and IL-12 are structurally similar and critical for the generation of efficient cellular immune responses. Toxoplasma gondii induces a strong cell-mediated immune response. However, little is known about IL-23 secretion profiles in T. gondii-infected immune cells in connection with IL-12. We compared the patterns of IL-23 and IL-12 production by THP-1 human monocytic cells in response to stimulation with live or heat-killed T. gondii tachyzoites, or with equivalent quantities of either T. gondii excretory/secretory proteins (ESP) or soluble tachyzoite antigen (STAg). IL-23 and IL-12 were significantly increased from 6 hr after stimulation with T. gondii antigens, and their secretions were increased with parasite dose-dependent manner. IL-23 concentrations were significantly higher than those of IL-12 at the same multiplicity of infection. IL-23 secretion induced by live parasites was significantly higher than that by heat-killed parasites, ESP, or STAg, whereas IL-12 secretion by live parasite was similar to those of ESP or STAg. However, the lowest levels of both cytokines were at stimulation with heat-killed parasites. These data indicate that IL-23 secretion patterns by stimulation with various kinds of T. gondii antigens at THP-1 monocytic cells are similar to those of IL-12, even though the levels of IL-23 induction were significantly higher than those of IL-12. The detailed kinetics induced by each T. gondii antigen were different from each other.
Assuntos
Antígenos de Protozoários/imunologia , Interleucina-12/metabolismo , Interleucina-23/metabolismo , Monócitos/imunologia , Monócitos/parasitologia , Toxoplasma/imunologia , Linhagem Celular , Humanos , Fatores de TempoRESUMO
Toxoplasma gondii can modulate host cell gene expression; however, determining gene expression levels in intermediate hosts after T. gondii infection is not known much. We selected 5 genes (ALDH1A2, BEX2, CCL3, EGR2 and PLAU) and compared the mRNA expression levels in the spleen, liver, lung and small intestine of genetically different mice infected with T. gondii. ALDH1A2 mRNA expressions of both mouse strains were markedly increased at day 1-4 postinfection (PI) and then decreased, and its expressions in the spleen and lung were significantly higher in C57BL/6 mice than those of BALB/c mice. BEX2 and CCR3 mRNA expressions of both mouse strains were significantly increased from day 7 PI and peaked at day 15-30 PI (P<0.05), especially high in the spleen liver or small intestine of C57BL/6 mice. EGR2 and PLAU mRNA expressions of both mouse strains were significantly increased after infection, especially high in the spleen and liver. However, their expression patterns were varied depending on the tissue and mouse strain. Taken together, T. gondii-susceptible C57BL/6 mice expressed higher levels of these 5 genes than did T. gondii-resistant BALB/c mice, particularly in the spleen and liver. And ALDH1A2 and PLAU expressions were increased acutely, whereas BEX2, CCL3 and EGR2 expressions were increased lately. Thus, these demonstrate that host genetic factors exert a strong impact on the expression of these 5 genes and their expression patterns were varied depending on the gene or tissue.
Assuntos
Aldeído Desidrogenase/genética , Quimiocina CCL3/genética , Proteína 2 de Resposta de Crescimento Precoce/genética , Proteínas do Tecido Nervoso/genética , Toxoplasma/fisiologia , Toxoplasmose/genética , Ativador de Plasminogênio Tipo Uroquinase/genética , Aldeído Desidrogenase/metabolismo , Família Aldeído Desidrogenase 1 , Animais , Encéfalo/metabolismo , Encéfalo/parasitologia , Quimiocina CCL3/metabolismo , Proteína 2 de Resposta de Crescimento Precoce/metabolismo , Perfilação da Expressão Gênica , Humanos , Pulmão/metabolismo , Pulmão/parasitologia , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Endogâmicos C57BL , Camundongos Endogâmicos , Proteínas do Tecido Nervoso/metabolismo , Especificidade de Órgãos , Retinal Desidrogenase , Baço/metabolismo , Baço/virologia , Toxoplasmose/metabolismo , Toxoplasmose/parasitologia , Ativador de Plasminogênio Tipo Uroquinase/metabolismoRESUMO
Heat-shock protein 70 (HSP70) is highly expressed in Toxoplasma gondii-infected cells. However, the role of this protein is not well understood, especially during apoptosis. This study addresses the mechanism behind the antiapoptotic chaperone activity of HSP70 in Toxoplasma-infected host cells using a human macrophage cell line, THP-1 by Western blot, DNA fragmentation assay, immunoprecipitation, and a caspase-3/7 activity assay based on cleavage of the colorimetric substrate DEVD-pNA. Apoptosis induced by arsenic trioxide (As(2)O(3)) was inhibited in T. gondii-infected THP-1 cells, but not in uninfected cells. Without As(2)O(3) induction of apoptosis, T. gondii infection caused increased expression of Bcl-2 and HSP70, but not caspase-3. However, active form caspase-3 levels were lower in As(2)O(3)-treated infected cells as compared with As(2)O(3)-treated uninfected cells. Bcl-2 expression in As(2)O(3)-treated infected cells was similar to that in cells infected with T. gondii. Translocation of apoptosis-inducing factor (AIF) and release of cytochrome c from mitochondria were inhibited in As(2)O(3)-treated infected cells as compared with As(2)O(3)-treated uninfected cells. Increased parasite loads in Toxoplasma-infected macrophages caused higher HSP70 and Bcl-2 expression in whole-cell extracts and fractionated components, respectively. However, expression of AIF and cytochrome c was unaffected. Toxoplasma dose-dependently inhibited caspase-3 activation, thus revealing an anti-apoptotic parasite activity on cytochrome c-mediated caspase activation in subcellular components. In addition, immunoprecipitation analysis suggested that HSP70 is capable of binding to the pro-apoptotic factors AIF and Apaf-1, but not to cytochrome c or procaspase-9. Taken together, these data demonstrate that T. gondii infection inhibits mitochondrial apoptosis through overproduction of anti-apoptotic Bcl-2 as well as HSP70, which are increased parasite loads dependently.
Assuntos
Apoptose , Proteínas de Choque Térmico HSP70/biossíntese , Macrófagos/parasitologia , Proteínas Proto-Oncogênicas c-bcl-2/biossíntese , Toxoplasma/patogenicidade , Trióxido de Arsênio , Arsenicais , Western Blotting , Caspase 3/metabolismo , Caspase 7/metabolismo , Linhagem Celular , Fragmentação do DNA , Humanos , Imunoprecipitação , Óxidos/toxicidadeRESUMO
We studied on the proteomic characteristics of Toxoplasma gondii KI-1 tachyzoites which were originally isolated from a Korean patient, and compared with those of the well-known virulent RH strain using 2-dimensional electrophoresis (2-DE), mass spectrometry, and quantitative real-time PCR. Two-dimensional separation of the total proteins isolated from KI-1 tachyzoites revealed up to 150 spots, of which 121 were consistent with those of RH tachyzoites. Of the remaining 29 spots, 14 showed greater than 5-fold difference in density between the KI-1 and RH tachyzoites at a pH of 5.0-8.0. Among the 14 spots, 5 from the KI-1 isolate and 7 from the RH strain were identified using MALDI-TOF mass spectrometry and database searches. The spots from the KI-1 tachyzoites were dense granule proteins (GRA 2, 3, 6, and 7), hypoxanthine-guanine-xanthine phosphoribosyltransferase (HGRPTase), and uracil phosphoribosyltransferase (UPRTase). The spots from the RH strain were surface antigen 1 (SAG 1), L-lactate dehydrogenase (LDH), actin, chorismate synthase, peroximal catalase, hexokinase, bifunctional dihydrofolate reductase-thymidylate synthase (DHTR-TS), and nucleoside-triphosphatases (NTPases). Quantitative real-time PCR supported our mass spectrometric results by showing the elevated expression of the genes encoding GRA 2, 3, and 6 and UPRTase in the KI-1 tachyzoites and those encoding GRA 7, SAG 1, NTPase, and chorismate synthase in the RH tachyzoites. These observations demonstrate that the protein compositions of KI-1 and RH tachyzoites are similar but differential protein expression is involved in virulence.
Assuntos
Proteômica , Proteínas de Protozoários/genética , Toxoplasma/crescimento & desenvolvimento , Toxoplasma/genética , Eletroforese em Gel Bidimensional , Regulação da Expressão Gênica no Desenvolvimento , Humanos , Dados de Sequência Molecular , Proteínas de Protozoários/química , Proteínas de Protozoários/metabolismo , Toxoplasma/química , Toxoplasma/metabolismo , Toxoplasmose/parasitologiaRESUMO
In this experiment, the correlation between antigenemia and specific antibody responses in Toxoplasma gondii-infected rabbits was assessed. We injected 1,000 T. gondii tachyzoites (RH) subcutaneously into 5 rabbits. Parasitemia, circulating antigens, and IgM and IgG antibody titers in blood were tested by ELISA and immunoblot. For detection of parasitemia, mice were injected with blood from rabbits infected with T. gondii and mice died between days 2 and 10 post-infection (PI). Circulating antigens were detected early on day 2 PI, and the titers increased from day 4 PI and peaked on day 12 PI. Anti-Toxoplasma IgM antibody titers increased on day 6 PI and peaked on days 14-16 PI. IgG was detected from day 10 PI, and the titers increased continuously during the experiment. The antigenic protein patterns differed during the infection period, and the number of bands increased with ongoing infection by the immunoblot analysis. These result indicated that Toxoplasma circulating antigens during acute toxoplasmosis are closely related to the presence of parasites in blood. Also, the circulating antigen levels were closely correlated with IgM titers, but not with IgG titers. Therefore, co-detection of circulating antigens with IgM antibodies may improve the reliability of the diagnosis of acute toxoplasmosis.
Assuntos
Anticorpos Antiprotozoários/sangue , Antígenos de Protozoários/sangue , Imunoglobulina G/sangue , Imunoglobulina M/sangue , Toxoplasma/imunologia , Toxoplasmose Animal/imunologia , Animais , Ensaio de Imunoadsorção Enzimática/métodos , Immunoblotting/métodos , Camundongos , Parasitemia , Coelhos , Fatores de Tempo , Toxoplasmose Animal/parasitologiaRESUMO
To figure out the epidemiological status and relevance with other diseases in toxoplasmosis, we checked serum IgG antibody titers of 1,265 patients and medical records of seropositive patients. Seropositive rates were 6.6% by latex agglutination test (LAT) and 6.7% by ELISA. No significant differences were detected between sexes and age groups. The peak seroprevalence was detected in the 40-49-year-old age group. According to clinical department, Toxoplasma-positive rates were high in patients in psychiatry, ophthalmology, health management, emergency medicine, and thoracic surgery. Major coincidental diseases in seropositive cases were malignant neoplasms, diabetes mellitus, arthritis, chronic hepatitis B, chronic renal diseases, schizophrenia, and acute lymphadenitis, in the order of frequency. In particular, some patients with chronic hepatitis B and malignant neoplasms had high antibody titers. These results revealed that the seroprevalence of toxoplasmosis in a general hospital-based study was similar to that in a community-based study, and T. gondii seropositivity may be associated with neoplasms, diabetes, and other chronic infections.
Assuntos
Toxoplasma/imunologia , Toxoplasmose/epidemiologia , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Animais , Anticorpos Antiprotozoários/sangue , Criança , Pré-Escolar , Comorbidade , Feminino , Hospitais Gerais , Humanos , Imunoglobulina G/sangue , Lactente , Recém-Nascido , Coreia (Geográfico)/epidemiologia , Masculino , Pessoa de Meia-Idade , Estudos Soroepidemiológicos , Adulto JovemRESUMO
A total of 351 serum samples was examined for anti-T. gondii antibody titers; the overall seroprevalence was 3.7%. The Sabin-Feldman dye test (DT), latex agglutination test (LAT), and IgG enzyme-linked immunosorbent assay (IgG ELISA) indicated seroprevalences of 3.7%, 3.4%, and 4.0%, respectively. Compared with the DT, the sensitivities of the LAT and IgG ELISA were 84.6% and 100.0%, respectively, and the specificities of the LAT and IgG ELISA were both 99.7%. An increase in T. gondii seroprevalence with increasing age was detected, but the difference was not significant. The overall seroprevalence of T. gondii-antibody titers in pregnant Korean women was relatively low compared to those of Europeans and Americans. A multivariate analysis of risk factors showed that T. gondii infection was positively correlated with eating raw meat, but was not associated with the consumption of unwashed vegetables, drinking untreated water, a history of raising a cat, or blood transfusion. The consumption of raw or undercooked meat may, therefore, be the main route of T. gondii infection in Korea.
Assuntos
Anticorpos Antiprotozoários/sangue , Complicações Parasitárias na Gravidez/epidemiologia , Toxoplasma/imunologia , Toxoplasmose/epidemiologia , Adulto , Animais , Gatos , Dieta , Técnica de Diluição de Corante , Ensaio de Imunoadsorção Enzimática , Feminino , Humanos , Coreia (Geográfico)/epidemiologia , Testes de Fixação do Látex , Pessoa de Meia-Idade , Gravidez , Fatores de Risco , Estudos SoroepidemiológicosRESUMO
PURPOSE: Surface antigen 3 (SAG3) of Toxoplasma gondii is very similar in structure to the major surface antigen 1 (SAG1). Although numerous studies have supported the importance of SAG1 in protection against T. gondii infection, few reports exist on SAG3. MATERIALS AND METHODS: Glutathione-S-transferase (GST)-fused SAG3 of T. gondii (rSAG3) were immunized into BALB/c mice alone or in combination with Quil A (rSAG3/Quil A), and then evaluated the protective immunity in vivo and in vitro against murine toxoplasmosis. RESULTS: Immunization with rSAG3 or rSAG3/Quil A resulted in significantly more survival days and fewer brain cysts after challenge with T. gondii compared to an infected control group. Mice immunized with rSAG3 alone or in combination with Quil A produced significantly more specific IgG2a antibody, whereas specific IgG1 antibody titers did not increase. The percentage of CD8+ T cells, IFN-gamma mRNA expression, and nitric oxide production significantly increased in rSAG3- and rSAG3/Quil A-immunized mice. CONCLUSION: These results indicate that vaccination with Toxoplasma rSAG3 results in partial protective immunity against T. gondii infection through induction of a Th1-type immune response, and that protective immunity is accelerated by the modulating effects of Quil A.
Assuntos
Antígenos de Protozoários/imunologia , Saponinas/imunologia , Toxoplasma/imunologia , Toxoplasmose Animal/imunologia , Vacinação/métodos , Animais , Antígenos de Protozoários/genética , Antígenos de Protozoários/metabolismo , Proteínas de Bactérias/genética , Proteínas de Bactérias/imunologia , Proteínas de Bactérias/metabolismo , Western Blotting , Ensaio de Imunoadsorção Enzimática , Feminino , Citometria de Fluxo , Imunoglobulina G/imunologia , Interferon gama/metabolismo , Camundongos , Camundongos Endogâmicos BALB C , Óxido Nítrico/metabolismo , Proteínas de Protozoários/genética , Proteínas de Protozoários/imunologia , Proteínas de Protozoários/metabolismo , Saponinas de Quilaia , Proteínas Recombinantes de Fusão/genética , Proteínas Recombinantes de Fusão/imunologia , Proteínas Recombinantes de Fusão/metabolismo , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Toxoplasma/crescimento & desenvolvimento , Toxoplasmose Animal/metabolismo , Toxoplasmose Animal/microbiologiaRESUMO
A 67-year-old Korean woman attended our hospital complaining of a severe headache. A brain computed tomography scan showed conglomerated, high-density, calcified nodules in the left temporo-occipito-parietal area and high-density subarachnoid hemorrhage in the basal cisterns. Magnetic resonance imaging of the brain shows multiple conglomerated iso- or low-signal intensity round nodules with peripheral rim enhancement. She underwent craniotomies to clip the aneurysm and remove the calcified masses. Paragonimus westermani eggs were identified in the calcified necrotic lesions. Results of parasitic examinations on the sputum and an enzyme-linked immunosorbent assay for P. westermani were all negative. The patient presented with headache and dizziness that had occurred for more than 30 years. She had not eaten freshwater crayfish or crabs. However, she had sometimes prepared raw crabs for several decades. Overall, this case was diagnosed as chronic cerebral paragonimiasis, in which she may have been infected through the contamination of utensils during the preparation of the second intermediate hosts, combined with a cerebral hemorrhage.
Assuntos
Infecções Parasitárias do Sistema Nervoso Central/diagnóstico , Doenças Cerebelares/diagnóstico , Paragonimíase/diagnóstico , Hemorragia Subaracnóidea/diagnóstico , Idoso , Infecções Parasitárias do Sistema Nervoso Central/complicações , Infecções Parasitárias do Sistema Nervoso Central/diagnóstico por imagem , Infecções Parasitárias do Sistema Nervoso Central/cirurgia , Doenças Cerebelares/complicações , Doenças Cerebelares/diagnóstico por imagem , Doenças Cerebelares/cirurgia , Diagnóstico Diferencial , Feminino , Humanos , Paragonimíase/complicações , Paragonimíase/diagnóstico por imagem , Paragonimíase/cirurgia , Hemorragia Subaracnóidea/complicações , Hemorragia Subaracnóidea/diagnóstico por imagem , Hemorragia Subaracnóidea/cirurgia , Tomografia Computadorizada por Raios XRESUMO
Toxoplasma gondii results in ocular toxoplasmosis characterized by chorioretinitis with inflammation and necrosis of the neuroretina, pigment epithelium, and choroid. After invasion, T. gondii replicates in host cells before cell lysis, which releases the parasites to invade neighboring cells to repeat the life cycle and establish a chronic retinal infection. The mechanism by which T. gondii avoids innate immune defense, however, is unknown. Therefore, we determined whether PI3K/Akt signaling pathway activation by T. gondii is essential for subversion of host immunity and parasite proliferation. T. gondii infection or excretory/secretory protein (ESP) treatment of the human retinal pigment epithelium cell line ARPE-19 induced Akt phosphorylation, and PI3K inhibitors effectively reduced T. gondii proliferation in host cells. Furthermore, T. gondii reduced intracellular reactive oxygen species (ROS) while activating the PI3K/Akt signaling pathway. While searching for the main source of these ROS, we found that NADPH oxidase 4 (Nox4) was prominently expressed in ARPE-19 cells, and this expression was significantly reduced by T. gondii infection or ESP treatment along with decreased ROS levels. In addition, artificial reduction of host Nox4 levels with specific siRNA increased replication of intracellular T. gondii compared to controls. Interestingly, these T. gondii-induced effects were reversed by PI3K inhibitors, suggesting that activation of the PI3K/Akt signaling pathway is important for suppression of both Nox4 expression and ROS levels by T. gondii infection. These findings demonstrate that manipulation of the host PI3K/Akt signaling pathway and Nox4 gene expression is a novel mechanism involved in T. gondii survival and proliferation.
Assuntos
Regulação para Baixo , NADPH Oxidases/metabolismo , Fosfatidilinositol 3-Quinases/metabolismo , Proteínas Proto-Oncogênicas c-akt/metabolismo , Transdução de Sinais , Toxoplasma/citologia , Animais , Linhagem Celular , Proliferação de Células , Ativação Enzimática , Humanos , NADPH Oxidase 4 , NADPH Oxidases/genética , RNA Interferente Pequeno/genética , Espécies Reativas de Oxigênio/metabolismo , Toxoplasma/enzimologia , Toxoplasma/metabolismoRESUMO
PURPOSE: Toxoplasmosis, which is caused by the protozoan parasite Toxoplasma gondii, can lead to severe visual impairment. T. gondii inhibits or delays programmed cell death caused by various apoptotic triggers; however, the mechanisms involved in the T. gondii-induced suppression of apoptosis in retinal cells have not been analysed in detail. METHODS: We investigated the role of T. gondii infection in H(2)O(2) -induced apoptosis in human retinal pigment epithelial cells (ARPE-19) by monitoring the activities of apoptosis-regulating molecules and mitogen-activated protein kinases (MAPKs), including p38 MAPK. We also examined the gene downstream from p38 MAPK. RESULTS: T. gondii infection significantly inhibited the cellular toxicity of H(2)O(2) (500 µm) and increased cell viability in a multiplicity of infection (MOI)-dependent manner by reducing DNA fragmentation and reactive oxygen species (ROS) generation in ARPE-19 cells. Western blot analysis also showed that T. gondii infection prevented the host cell expression of pro-apoptotic factors, such as Bad and Bax, and the activation of caspase-3. Infection with T. gondii increased the expression of the anti-apoptotic factor Bcl-2 in ARPE-19 cells under oxidative stress. In accordance with these findings, Toxoplasma infection was protective enough to suppress the phosphorylation of p38 MAPK following H(2)O(2) treatment. Exposure to H(2)O(2) increased the expression of heme oxygenase-1 (HO-1) in ARPE-19 cells, and its expression was significantly inhibited in H(2)O(2) -treated infected cells. CONCLUSION: The protective function of T. gondii infection against ROS-induced apoptosis results from changes in the expression of apoptotic molecules and the downregulation of stress-induced intracellular signalling.
Assuntos
Proteínas Reguladoras de Apoptose/genética , Apoptose/efeitos dos fármacos , Peróxido de Hidrogênio/toxicidade , Epitélio Pigmentado da Retina/efeitos dos fármacos , Epitélio Pigmentado da Retina/parasitologia , Toxoplasma/fisiologia , Proteínas Quinases p38 Ativadas por Mitógeno/genética , Proteínas Reguladoras de Apoptose/metabolismo , Western Blotting , Linhagem Celular , Sobrevivência Celular , Fragmentação do DNA/efeitos dos fármacos , Eletroforese em Gel de Ágar , Eletroforese em Gel de Poliacrilamida , Inibidores Enzimáticos/farmacologia , Regulação da Expressão Gênica/fisiologia , Heme Oxigenase-1/genética , Heme Oxigenase-1/metabolismo , Humanos , Fosforilação , RNA Mensageiro/metabolismo , Espécies Reativas de Oxigênio/metabolismo , Epitélio Pigmentado da Retina/metabolismo , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Proteínas Quinases p38 Ativadas por Mitógeno/metabolismoRESUMO
Toxoplasma gondii is an obligate intracellular protozoan parasite that induces antitumor activity against certain types of cancers. However, little information is available regarding the immunologic mechanisms that regulate these effects. For this purpose, C57BL/6 mice were administered either the T. gondii Me49 strain orally or Lewis lung carcinoma (LLC) cells intramuscularly. Survival rates, tumor size, histopathology, and immune responses were determined for each group, and angiogenesis was evaluated by in vivo Matrigel plug assay. Toxoplasma-infected (TG-injected) mice survived the entire experimental period, whereas cancer cell-bearing (LLC-injected) mice died within six weeks. Mice injected with both T. gondii and cancer cells (TG/LLC-injected group) showed significantly increased survival rates, CD8+ T-cell percentages, IFN-gamma mRNA expression levels, serum IgG2a titers, and CTL responses as compared to the LLC-injected mice. In addition, angiogenesis in the TG/LLC-injected mice was notably inhibited. These effects in TG/LCC-injected mice were similar or were increased by the addition of an adjuvant, Quil-A. However, TG/LLC-injected mice showed decreased percentages of CD4+ and CD8+ T cells, IFN-gamma mRNA expression levels, and serum IgG1 and IgG2a titers as compared to TG-injected mice. Taken together, our results demonstrate that T. gondii infection inhibits tumor growth in the Lewis lung carcinoma mouse model through the induction of Th1 immune responses and antiangiogenic activity.
Assuntos
Carcinoma Pulmonar de Lewis/terapia , Imunoterapia/métodos , Células Th1/imunologia , Toxoplasma/imunologia , Animais , Sequência de Bases , Linfócitos T CD4-Positivos/imunologia , Linfócitos T CD8-Positivos/imunologia , Carcinoma Pulmonar de Lewis/irrigação sanguínea , Carcinoma Pulmonar de Lewis/genética , Carcinoma Pulmonar de Lewis/imunologia , Linhagem Celular Tumoral , Citotoxicidade Imunológica , Primers do DNA/genética , Feminino , Imunoglobulina G/sangue , Técnicas In Vitro , Interferon gama/genética , Camundongos , Camundongos Endogâmicos C57BL , Neovascularização Patológica , RNA Mensageiro/genética , RNA Mensageiro/metabolismoRESUMO
Toxoplasma gondii has been shown to result in life-threatening encephalitis in immunocompromised patients after reactivation of dormant parasites. In order to obtain information on immune responses related to this phenomenon, BALB/c mice were infected with 25 cysts of the 76K strain of T. gondii, then, treated orally with dexamethasone (Toxo/Dexa-treated group) in order to reactivate the chronic toxoplasmosis. None of the T. gondii-infected mice died during the experimental periods, whereas the Toxo/Dexa-treated mice evidenced a significant attenuation of survival periods. Toxoplasma-specific IgG2a, IgA and IgM titers in sera were significantly depressed in the Toxo/Dexa-treated mice; however, the IgG1 sera titers were similar to those seen in the Toxoplasma-infected mice. The percentages of CD4+ and CD8 alpha + T cells in the Toxo/Dexa-treated mice were significantly reduced 2 weeks after dexamethasone treatment. IFN-gamma and IL-10 production levels in the Toxo/Dexa-treated mice were depressed significantly, whereas IL-4 production was increased temporarily. The expression levels of the Toxoplasma-specific P30 and B1 genes were found to have been increased in the Toxo/Dexa-treated mice in comparison with the Toxoplasmainfected mice. Collectively, the findings of this study demonstrate that reactivation of murine toxoplasmosis as the result of dexamethasone treatment induced a depression in Th1 immune responses, whereas Th2 immune responses were not significantly influenced.
Assuntos
Anticorpos Antiprotozoários/biossíntese , Citocinas/biossíntese , Dexametasona/farmacologia , Imunoglobulinas/biossíntese , Toxoplasma/imunologia , Toxoplasmose/imunologia , Animais , Anticorpos Antiprotozoários/imunologia , Feminino , Imunoglobulinas/imunologia , Camundongos , Camundongos Endogâmicos BALB C , Células Th1/imunologia , Células Th2/imunologia , Toxoplasmose/parasitologiaRESUMO
Prevalence of sparganum in the frog (Rana nigromaculata) was surveyed in Dae-jeon city and in suburbs of the city, Chungnam Do. 39 (3.9 %) out of 1,011 frogs were infected with the worm, and the highest prevalence rate of sparganum was found the frogs from Shintanjin area(11.3 %). Infection rates of sparganum were observed due to the body weight and sex of frogs. The highest infection rate of frogs, the body weight of 50 gms or more, showed 30.3 per cent(female: 41.7 %, male: none), on the other hand, no worm was found in young frogs(less than 10 gms). Distribution of sparganum in the frogs was recorded and 82.6 % of worms were distributed in the femoral intermuscular connective tissues of the hind legs. Among those infected frogs, number of worm burden was one to five worms, and 53.3 per cent of frogs were infected by only one worm.
RESUMO
Although there are many reports on the splenic (systemic) T cell response after Toxoplasma gondii infection, little information is available regarding the local T cell responses of peritoneal exudate cells (PEC) and gut intraepithelial lymphocytes (IEL) following peroral infection with bradyzoites. Mice were infected with 40 cysts of the 76K strain of T. gondii, and then sacrificed at days 0, 1, 4, 7 and 10 postinfection (PI). The cellular composition and T cell responses of PEC and IEL were analyzed. The total number of PEC and IEL per mouse increased after infection, but the ratio of increase was higher in IEL. Lymphocytes were the major component of both PEC and IEL. The relative percentages of PEC macrophages and neutrophils/eosinophils increased significantly at day 1 and 4 PI, whereas those of IEL did not change significantly. The percentage of PEC NK1.1 and gamma delta T cells peaked at day 4 PI (p < 0.0001), and CD4 and CD8 alpha T cells increased continuously after infection. The percentages of IEL CD8 alpha and gamma delta T cells decreased slightly at first, and then increased. CD4 and NK1.1 T cells of IEL did not change significantly after infection. IFN-gamma-producing PEC NK1.1 T cells increased significantly from day 1 PI, but the other T cell subsets produced IFN-gamma abundantly thereafter. The proportion of IEL IFN-gamma-producing CD8 alpha and gamma delta T cells increased significantly after infection, while IEL NK1.1 T cells had similar IFN-gamma production patterns. Taken together, CD4 T cells were the major phenotype and the important IFN-gamma-producing T cell subsets in PEC after oral infection with T. gondii, whereas CD8 alpha T cells had these roles in IEL. These results suggest that PEC and IEL comprise different cell differentials and T cell responses, and according to infection route these factors may contribute to the different cellular immune responses.
Assuntos
Líquido Ascítico/metabolismo , Interferon gama/biossíntese , Linfócitos/metabolismo , Subpopulações de Linfócitos T/imunologia , Toxoplasmose/imunologia , Doença Aguda , Animais , Líquido Ascítico/citologia , Feminino , Mucosa Intestinal/citologia , Camundongos , Camundongos Endogâmicos C57BLRESUMO
To evaluate the role of nitric oxide (NO) in IFN-gamma production and apoptosis of splenocytes in genetically different strains of mice with toxoplasmosis, BALB/c (a toxoplasmosis resistant strain) and C57BL/6 (a toxoplasmosis susceptible strain) mice were infected with Toxoplasma gondii cysts orally and subsequently injected intraperitoneally with aminoguanidine, an iNOS inhibitor (AG; 35 mg/kg per mouse daily for 14 days). When BALB/c or C57BL/6 mice were infected with T. gondii without AG treatment, number of brain cysts, NO and IFN-gamma production by splenocytes, and percentages of apoptotic splenocytes were increased compared to uninfected control mice without AG treatment. AG treatment increased the number of brain cysts, and reduced NO and IFN-gamma production in T. gondii-infected C57BL/6 mice. In contrast, in T. gondii-infected BABL/c mice, the number of brain cysts, and NO and IFN-gamma production of splenocytes was not altered by treatment with AG. However, the percentages of apoptotic splenocytes in T. gondii-infected BALB/c or C57BL/6 mice were not affected by AG treatment. These results suggest that NO modulates IFN-gamma production in T. gondii-infected C57BL/6 mice, and that NO is involved in mediating a protective response in toxoplasmosis susceptible, but not resistant, mice strain during acute infection.
Assuntos
Apoptose/imunologia , Guanidinas/farmacologia , Interferon gama/biossíntese , Óxido Nítrico Sintase/antagonistas & inibidores , Óxido Nítrico/biossíntese , Toxoplasmose Animal/imunologia , Animais , Apoptose/efeitos dos fármacos , Feminino , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Endogâmicos C57BL , Óxido Nítrico Sintase Tipo II , Especificidade da Espécie , Baço/imunologiaRESUMO
The endemic status of clonorchiasis and metagonimiasis along the Geum-gang (River) in Okcheon-gun (County) in Korea was examined. From February to December 2000, stools of total 1,081 inhabitants living in 5 villages were examined. Each stool specimen was examined by both the cellophane thick smear method and the formalin-ether sedimentation technique. Egg-positive cases were further analyzed by Stoll's egg-counting technique, and praziquantel was administered to positive cases. The egg-positive rates for Clonorchis sinensis and Metagonimus species were 9.3% and 5.5%, respectively, and the double infection rate was 3.5%. The numbers of eggs per gram (EPG) of feces of C. sinensis and Metagonimus sp. were 918 +/- 1,463 and 711 +/- 947, respectively. The egg-positive rates for C. sinensis and Metagonimus sp. in the riverside area were 14.2% and 8.4%, respectively, which were significantly higher than those of the inland area (3.2% and 1.7%, respectively). The egg-positive rates of C. sinensis and Metagonimus sp. in males (16.7% and 10.0%) were significantly higher than those of females (3.5% and 1.8%). However, there were no significant differences of EPG values between localities and sexes. The prevalence of clonorchiasis and metagonimiasis in this survey was significantly lower than that in the previous reports. However, there is still a high prevalence of infection with C. sinensis and Metagonimus sp. in this region, especially in the riverside area.