• Parasites, Hosts and Diseases
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• v.48 no.2
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• pp.171-174
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• 2010

The anti-tumorigenic effects of Toxoplasma gondii (RH) antigens were studied in a murine sarcoma-180 tumor model. To determine the anti-tumor effects, the reduction in tumor size and expression of CD31 (an angiogenesis marker in the tumor tissue) were examined after injection of BALB/c mice with T. gondii lysate antigen (TLA) or formalin-fixed, proliferation-inhibited, T. gondii tachyzoites. Tumors were successfully produced by an intradermal injection of sarcoma-180 cells with plain Matrigel in the mid-backs of mice. After injection with TLA or formalin-fixed T. gondii tachyzoites, the increase in tumor size and weight nearly stopped while tumor growth continued in control mice that were injected with PBS. CD31 expression in TLA-treated or formalin-fixed T. gondii-injected mice was lower than the control mice. Accordingly, the present study shows that the treatment of mice with formalin-fixed T. gondii or TLA in the murine sarcoma-180 tumor model results in a decrease of both tumor size and CD31 expression.

• Parasites, Hosts and Diseases
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• v.43 no.1 s.133
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• pp.19-25
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• 2005

Protective efficacy of vaccination with Neospora caninum multiple recombinant antigens against N. caninum infection was evaluated in vitro and in vivo. Two major immunodominant surface antigens (NcSAG1 and NcSRS2) and two dense granule proteins (NcDG1 and NcDG2) of N. caninum tachyzoites were expressed in E. coli, respectively. An in vitro neutralization assay using polyclonal antisera raised against each recombinant antigen showed inhibitory effects on the invasion of N. caninum tachyzoites into host cells. Separate groups of gerbils were immunized with the purified recombinant proteins singly or in combinations and animals were then challenged with N. caninum. Following these experimental challenges, the protective efficacy of each vaccination was determined by assessing animal survival rate. All experimental groups showed protective effects of different degrees against experimental infection. The highest protection efficacy was observed for combined vaccination with NcSRS2 and NcDG1. Our results indicate that combined vaccination with the N. caninum recombinant antigens, NcSRS2 and NcDG1, induces the highest protective effect against N. caninum infection in vitro and in vivo.

• Journal of Physiology & Pathology in Korean Medicine
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• v.22 no.1
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• pp.96-99
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• 2008

Toxoplasma gondiiis a widespread apicomplexan parasite which is able to infect virtually all warm-blooded vertebrates. Twenty-two percent of the U.S. population is infected, but severe disease in adults is mainly limited to immunosuppressed patients. In patients with acquired immunodeficiency syndrome(AIDS), T. gondii causes a life-threatening opportunistic infection, with Toxoplasma encephalitis as its most severe manifestations. T. gondii is also known to cause congenital infection and is among the pathogens with the highest incidence of complications in pregnancies. Despite its clinical importance, only very few therapeutic drugs against T. gondii are available, all of which target the rapidly dividing tachyzoites, leaving the dormant encysted bradyzoite stage unaffected. We searched 15 traditional medicines that have anti-inflammatory effect from dongyibogam and Traditional Chinese medicine. In vitro studies were performed with HeLa cell cultures, with quantification of Toxoplasma growth by a cell proliferation assay. The result of experiment shows the selectivity of Citrus unshiu Markovich is 6.0. This is higher than sulfadiazine (selectivity was 1.63). For in vivo studies, mice were acutely infected intraperitoneally with $10^5$ tachyzoites of the virulent RH strain and then treated per orally for 4 days from 6 hours postinfection. Efficacy was assessed by sequential determination of parasite burdens in peritoneal cavity. In vivo, Citrus unshiu Markoviche inhibited Toxoplasma growth at a concentration of 10㎎/㎏ of body weight per day, the inhibition ratio was estimated to be 64.01%.

• Parasites, Hosts and Diseases
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• v.47 no.2
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• pp.117-124
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• 2009

Toxoplasma gondii provokes rapid and sustained nuclear translocation of the signal transducer and activator of transcription 6 (STAT6) in HeLa cells. We observed activation of STAT6 as early as 2hr after infection with T. gondii by the nuclear translocation of fluorescence expressed from exogenously transfected pDsRed2-STAT6 plasmid and by the detection of phosphotyrosine-STAT6 in Western blot. STAT6 activation occurred only by infection with live tachyzoites but not by co-culture with killed tachyzoites or soluble T. gondii extracts. STAT6 phosphorylation was inhibited by small interfering RNA of STAT6 (siSTAT6). In view of the fact that STAT6 is a central mediator of IL-4 induced gene expression, activation of STAT6 by T. gondii infection resembles that infected host cells has been stimulated by IL-4 treatment. STAT1 was affected to increase the transcription and expression by the treatment of siSTAT6. STAT6 activation was not affected by any excess SOCS's whereas that with IL-4 was inhibited by SOCS-1 and SOCS-3. T. gondii infection induced Eotaxin-3 gene expression which was reduced by $IFN-{\gamma}$. These results demonstrate that T. gondii exploits host STAT6 to take away various harmful reactions by $IFN-{\gamma}$. This shows, for the first time, IL-4-like action by T. gondii infection modulates microbicidal action by $IFN-{\gamma}$ in infected cells.

• Journal of Pharmacopuncture
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• v.22 no.3
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• pp.154-159
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• 2019

Objectives: Toxoplasmosis is a worldwide health problem that caused by intracellular apicomplexan parasite, Toxoplasma gondii (T. gondii). Considering that the available drugs for toxoplasmosis have serious host toxicity, the aim of the current study was to survey the in vitro and in vivo anti-Toxoplasma activity of Zea mays (Z. mays) and Eryngium caucasicum (E. caucasicum) extracts. Methods: Four concentrations (5, 10, 25, and $50mg\;mL^{-1}$) of Z. mays and E. caucasicum methanolic extracts for 30, 60, 120, and 180 min were incubated with infected macrophages and then the viability of RH strain of T. gondii tachyzoites was evaluated by trypan blue staining method. Also, we evaluated the survival rate of acutely infected mice with the extracts (100 and $200mg\;kg^{-1}\;day^{-1}$) intraperitoneally for 5 days after infection with $2{\times}104$ tachyzoites of T. gondii. Results: The anti-Toxoplasma effect of the methanolic extracts were extremely significant compared to the negative control group in all exposure times (P < 0.05). The Z. mays (10, 25 and $50mg\;mL^{-1}$) killed 100% of the parasites after 180 and 120 min exposure, respectively. Also, high toxoplasmacidal activity was observed with E. caucasicum extract. Furthermore, treatment of experimentally infected mice with the Z. mays (100, $200mg\;kg^{-1}\;day^{-1}$) and E. caucasicum ($100mg\;kg^{-1}\;day^{-1}$) significantly increased their survival rate compared to untreated infected control (P < 0.05). Conclusion: These extracts are promising candidates for further medicine development on toxoplasmosis. However, further investigations are necessary to clarify effective fractions of the Z. mays and E. caucasicum extracts and the mechanisms of action.

• Parasites, Hosts and Diseases
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• v.38 no.2
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• pp.65-74
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• 2000

Toxoplasma-killing activities of mouse peritoneal macrophages activated by the extracts of Tetrahymena pyriformis (Korean and Chinese strains) were evaluated, and the active protein fractions from both strains were partially characterized by a method including chromatographies and SDS-PAGE. The first peak in Korean strain and the second peak in Chinese strain of T. pyriformis obtained by DEAE-Sephadex A-50 chromatography were most effective in the activation of macrophages to kill Toxoplasma gondii tachyzoites in vitro. Subsequent fractionations of obtained peak fractions were performed on a Sephadex G-200 gel. The first peaks fractionated from both strains of T. pyrtyomis had the highest toxoplasmacidal activities, and when subjected to the SDS-PAGE, one prominent band was visualized for each of the strains showing the same molecular weight of ca. 52.6 kDa. This active protein is suggested to be related to non-specific activation of mouse peritoneal macrophages.

• Journal of Veterinary Clinics
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• v.21 no.1
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• pp.80-82
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• 2004

A 3 month-old male dog with clinical signs of anorexia, soft stool, ocular and nasal discharge, cough and respiratory distress was submitted to the Cheju National University for diagnosis. At necropsy, tan to pulp]e-red sublobar to lobar consolidations were presented in apical and cardiac lobe of lung. Histopathologically, severe diffuse bronchointerstitial pneumonia with necrotic bronchiolitis was noted in the lung. The demyelinating encephalitis and astrocytosis were presented in cerebellum and cerebrum. Numerous round, ovoid or cluster of tachyzoites were also identified in alveolar lumen, alveolar wall and cytoplasm of macrophages in the lung. The orgasnisms were demonstrated as Toxoplasma (T) gondii by immunohistochemistry. Intranuclear or intracytoplasmic eosinophilic inclusion bodies were seen in the glial cells of the cerebellum. Canine distemper virus (CDV) specific antigens were demonstrated in the cerebellum by the immunohistochemistry. In our knowledge, this is believed to be the first confirmed report of co-infection of CDV and T gondii in dog in Korea.

• Parasites, Hosts and Diseases
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• v.56 no.5
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• pp.437-446
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• 2018

To investigate the prevalence of Toxoplasma gondii in pork on the market in Korea, an in-house enzyme-linked immunosorbent assay for tissue fluid (CAU-tf-ELISA) was developed using a soluble extract of T. gondii RH strain tachyzoites. As the standard positive controls, the piglets were experimentally infected with T. gondii: Group A (1,000 cysts-containing bradyzoites), Group B (500 cysts-containing bradyzoites) and Group C ($1.0{\times}10^3$ or $1.0{\times}10^4$ tachyzoites). The CAU-tf-ELISA demonstrated infection intensity-dependent positivity toward tissue fluids with average cut-off value 0.15: 100% for Group A, 93.8% for Group B and 40.6% for Group C. When tissue-specific cut-off values 0.066-0.199 were applied, CAU-tf-ELISA showed 96.7% sensitivity, 100% specificity, 100% positive and 90.0% negative predictive values. When compared with the same tissue fluids, performance of CAU-tf-ELISA was better than that of a commercial ELISA kit. Of the 583 Korea domestic pork samples tested, anti-T. gondii antibodies were detected from 9.1% of whole samples and 37.9% from skirt meat highest among pork parts. In the 386 imported frozen pork samples, 1.8% (skirt meat and shoulder blade) were positive for anti-T. gondii antibodies. In Korea, prevalence of anti-T. gondii antibodies in the pork on retail markets appeared high, suggesting that regulations on pig farming and facilities are necessary to supply safe pork on the tables.

• Parasites, Hosts and Diseases
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• v.29 no.2
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• pp.129-138
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• 1991

Tetrahymena pyriformis is a free-living ciliate protozoan in the freshwater system. Experiments were carried out to determine whether intraperitoneal administration of T. pyriformis (GL strain) to mice activates macrophages to be able to kill Toxoplasma gondii tachyzoites in vitro. Mice were also injected intraperitoneally with several synthetic activators; dimethyldioctadecylammonium bromide (DDA), dextran sulfate, complete Freund's adjutant (CFA) as well as Toxoplasma and Tetrehymena Iysates in order to activate mouse peritoneal macrophages. One week after the administration of activators, peritoneal cells were harvested and the adherent macrophages were challenged with Toxoplasma tachyzoites. Macrophage monolayers were then fixed with absolute methanol after washing, and stained with Giemsa solution. The percentage of the adherent cells infected and total number of organisms per 100 macrophages were calculated to make toxoplasma-cidal activity of macrophages according to the cultivation time. Peritoneal macrophages from mice administered with Tetrahymena exhibited significant protection against target parasites as compared with those treated with synthetic activators. Among non-biological synthetic activators, DDA was evaluated as an ellcellent activator.

• Korean Journal of Veterinary Research
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• v.31 no.4
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• pp.491-500
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• 1991

This study was conducted to detect the serum antibodies in the experimentally toxoplasma infected dogs and street dogs by use the of an enzyme-linked immunosorbent assay (ELISA). And this test was performed on the polystylene microplate by coating with the tachyzoites soluble antigen of T gondii (RH strain), incubated with sera diluted then, added with HPO-conjugated rabbit anti-dog IgG and o-phenylenediamine used as a substrate. Tachyzoites of T gondii harvested from mouse peritoneal cavity were purified by 30, 40 and 50% Percoll density gradient centrifugation and used as the source of antigen. The results obtained were summarized as follows; 1. The highest ratio of positive to negative (P/N ratio) was obtained at the level of $l{\mu}g/ml$ protein concentration of antigen with the 1/4000 dilution of the conjugate measured by checker-board titration. It was regarded as the optimum concentration of the antigen and conjugate. 2. Cut-off value in this IgG ELISA was 0.375 that was determined by mean absorbance (at 492nm) of IFA negative serum added with the dauble value of the standard deviation $(mean{\pm}2S.D.)$. 3. Serum ELISA IgG antibodies to T gondii in the exyerimentally infected dogs were detected firstly at the Week 3 after inoculation and the highest titer was recognized at the Week 4, 5 and 6 after inoculation. 4. Stability of the antigen absorbed in the microplates that were preserved at $4^{\circ}C$ and $-25^{\circ}C$ separately were prolonged up to 3 weeks and 10 weeks at $4^{\circ}C$ and $-25^{\circ}C$, respectively. However the reproducibility was not reliable after the preservation of 4 weeks and longer. 5. Positive rate of the specific antibodies in 312 test sera was 28.5% and there was no significant differences between the male (27.8%) and female (29.5%), respectively. 6. The IgG ELISA was proved to be a specific procedure for the detection of antibodies to canine toxoplasma infection and also evaluated as a screening test for the large scale of test samples in laboratory.