• Parasites, Hosts and Diseases
• /
• v.46 no.1
• /
• pp.45-48
• /
• 2008

To evaluate the usefulness of the Korean Isolate-1 (KI-1) antigen for serodiagnosis of toxoplasmosis, antigen profiles of KI-1 tachyzoites were analyzed in comparison with RH tachyzoites by SOS-PAGE and immunoblotting. ELISA was performed on latex agglutination (LA)-positive and negative serum samples using KI-1 and RH antigens. Immunoblotting of the KI-1 antigen showed multiple antigen bands with molecular sizes of 22-105 kDa. Among them, 1 and 6 common bands were noted against a KI-1-infected and a RH-infected human serum, respectively, which represented differences in antigenic profiles between KI-1 and RH tachyzoites. However, all 9 LA-positive human sera were found positive by ELISA, and all 12 LA-negative sera were negative by ELISA; the correlation between the ELISA titers and LA titers was high (r = 0.749). Our results suggest that tachyzoites of KI-1 may be useful for serodiagnosis of human toxoplasmosis.

• Korean Journal of Veterinary Service
• /
• v.43 no.4
• /
• pp.251-256
• /
• 2020

Two suckling piglets, 4 days and 10 days of age, showed lethargy and dyspnea after birth and mortality had been increased after incoming gilts from breeding farm. At necropsy, the lungs showed diffuse fail to collapse with rubbery consistency, edematous dilatation of interlobular septa, and lobular consolidation with purple red color. Heart was diffuse pale in color and had several irregular linear-shaped macules or patches. Histopathologically, diffuse interstitial pneumonia with the proliferation of type II pneumocytes was present in the lungs of 2 piglets. Alveolar lumens contained necrotic cellular debris derived from neutrophils and macrophages. Multifocal hemorrhage and necrotizing pneumonia with protozoan tachyzoites were observed in the lungs. Severe multifocal to confluent necrotic myocarditis, necrotic encephalitis, and necrotic adrenalitis with intralesional protozoan tachyzoites were observed in piglets. According to immunohistochemical analysis (IHC), Toxoplasma (T.) gondii tachyzoites antigens were confirmed in lung, heart, brain, and adrenal gland. And porcine reproductive and respiratory syndrome virus (PRRSV) antigens were also detected in the cytoplasm of macrophages in lungs using IHC. Based on the gross, histopathologic and immunohistochemical features, two suckling piglets were diagnosed as co-infection of T. gondii and PRRSV.

• Parasites, Hosts and Diseases
• /
• v.31 no.3
• /
• pp.215-222
• /
• 1993

In order to establish a useful cell culture system for T gondii we compared the degree of proliferation of T gondii tachyzoites among 8 different cell lines: 2 kinds of normal animal cells (MDCK-canine kidney cells; Vero-monkey kidney cells) and 6 kinds of human tumor cells (A 549, PC 14-lung cancer cells; SNU 1, SNU 16. Mlm 45-stomach cancer cells; HL-60-promyelocytic leukemia cells), through morphological observation and 3H-uracil uptake assay. The degree of susceptibility to infection with T gondii tachyzoites was highest in A 549 and PC 14 cells, medium in Vero, HL-60, MDCK and SNU 1, and lowest in SNU 16 and MBm 45 cells. The kinetics of T gondii multiplication during the post-Infection 60 hours were higllly dependent upon the dose of tachyzoites administered and the duration among the 8 tested fur the growth and multiplication of T gondii in vitro.

• Parasites, Hosts and Diseases
• /
• v.33 no.2
• /
• pp.131-134
• /
• 1995

When tachyzoites (RH strain) of Toxoplasmo gondii are injected intramuscularly, experimental mice survive up to 7 days, 1-2 days longer than those infected intraperitoneally. We observed sequential histopathological changes in inguinal Iymph nodes after intramuscular injection of tachyzoites to thighs of specific pathogen free (SPF) mice. Initial findings on 1 or 3 days after the injection were reactive germinal centers, distended sinuses and epithelioid cell clusters in cortical and paracortical regions. Later on 5 days after the injection, however, effacement of nodal structure with depletion of cells and focal necrosis were observed . Necrotizing Iymphadenitis in the experimental murine toxoplasmosis suggests the causal relation between T. gondii infection and the human disease.

• Parasites, Hosts and Diseases
• /
• v.53 no.2
• /
• pp.155-162
• /
• 2015

Toxoplasma gondii is a protozoan parasite with a broad range of intermediate hosts. Chickens as important food-producing animals can also serve as intermediate hosts. To date, experimental studies on the pathogenicity of T. gondii in broiler chickens were rarely reported. The objective of the present study was to compare the pathogenicity of 5 different T. gondii strains (RH, CN, JS, CAT2, and CAT3) from various host species origin in 10-day-old chickens. Each group of chickens was infected intraperitoneally with $5{\times}10^8$, $1{\times}10^8$, $1{\times}10^7$, and $1{\times}10^6$ tachyzoites of the 5 strains, respectively. The negative control group was mockly inoculated with PBS alone. After infection, clinical symptoms and rectal temperatures of all the chickens were checked daily. Dead chickens during acute phage of the infection were checked for T. gondii tachyzoites by microscope, while living cases were checked for T. gondii infection at day 53 post-inoculation (PI) by PCR method. Histopathological sections were used to observe the pathological changes in the dead chickens and the living animals at day 53 PI. No significant differences were found in survival periods, histopathological findings, and clinical symptoms among the chickens infected with the RH, CN, CAT2, and CAT3 strains. Histopathological findings and clinical symptoms of the JS (chicken origin) group were similar to the others. However, average survival times of infected chickens of the JS group inoculated with $5{\times}10^8$ and $1{\times}10^8$ tachyzoites were 30.0 and 188.4 hr, respectively, significantly shorter than those of the other 4 mammalian isolates. Chickens exposed to $10^8$ of T. gondii tachyzoites and higher showed acute signs of toxoplasmosis, and the lesions were relatively more severe than those exposed to lower doses. The results indicated that the pathogenicity of JS strain was comparatively stronger to the chicken, and the pathogenicity was dose-dependent.

• Korean Journal of Veterinary Research
• /
• v.38 no.1
• /
• pp.139-145
• /
• 1998

The Neospora sp. was isolated from the brain of 1 calf via continuous in vitro cultivation in Vero cell. Neospora tachyzoites were observed 45 days after inoculation of the homogenized brain suspension into the Vero cell. The isolated parasite (named tentatively as NCKB-1) was morphologically and ultrastructurally similar to the previously reported Neospora sp isolated in cattle (BPA-1, JPA-1). A comparison of the antigenic reactivity of cultivated tachyzoites with polyclonal antisera to Neospora caninum and Toxoplasma gondii confirmed that this protozoal isolate was similar to N caninum. This is the first report of successful isolation of Neospora sp from cattle in Korea.

• Parasites, Hosts and Diseases
• /
• v.48 no.4
• /
• pp.325-329
• /
• 2010

Toxoplasma gondii KI-1, a recent new isolate from Korea, shows similar pathogenicity and infectivity to mice compared to the virulent RH strain. To understand characteristics of host immunity, including immune enhancement or suppression, we investigated proliferative responses and phenotypes of spleen cells. In addition, kinetics of IFN-${\gamma}$, a Th1 cytokine, was examined in BALB/c mice up to day 6 post-infection (PI). Intraperitoneal injection of mice with $10^3$ KI-1 tachyzoites induced significant decreases (P < 0.05) in proliferative responses of spleen cells. This occurred at days 2-6 PI even when concanavalin A (con A) was added and when stimulated with KI-1 antigen, suggesting suppression of the immunity. $CD4^+$ T-cells decreased markedly at day 2 PI (P < 0.05), whereas $CD8^+$ T-cells, NK cells, and macrophages did not show significant changes, except a slight, but significant, increase of $CD8^+$ T-cells at day 6 PI. The capacity of splenocytes to produce IFN-${\gamma}$ by con A stimulation dropped significantly at days 2-6 PI. These results demonstrate that intraperitoneal injection of KI-1 tachyzoites can induce immunosuppression during the early stage of infection, as revealed by the decrease of $CD4^+$ T-cells and IFN-${\gamma}$.

• Parasites, Hosts and Diseases
• /
• v.26 no.3
• /
• pp.155-162
• /
• 1988

Surface membrane proteins of virulent RH strain and tissue cyst-forming Fukaya strain of Toxoplasma gondii were analysed by SDS-polyacrylamide gel electrophoresis after LPO-catalyzed surface iodination and lectin blotting, then identified the zoite-specific antigens. Prior to the analyses, purification of RH tachyzoites from mouse peritoneal exudate and of Fukaya bradyzoites from mouse brain tissues were performed by centrifugation - on the discontinuous Percoll density-gradient. Ta- chysoites were obtained at the interface of 50U and 60% Percoll solution and brain cysts were harvested at the interfaces of 40-50% and 50-60%, then bradyzoites were obtained by treating the cysts with hypertonic solution. The LPO-catalyzed iodination detected 15 KDa and 14 KDa proteins o( brady- zoites and 30 KDa protein of tachysoites as major bands with several other minor bands. But Con A blotting revealed some bands of 200 K∼50 KDa glycoproteins of bradyzoites and 52 KDa band as major and minor bands of 33 K∼20 KDa of tachyzoites. Phytohemagglutinin did not detect any band in the two forms. EITB with anti- Fukaya antibody and anti-RH antibody revealed cross-reactivities between the two forms. Despite the cross-reactivity, anti-Fukaya antibody reacted with 15 KDa band of bradyzoites specifically and, anti-RH antibody with 52 KDa, 30 KDa, and 25 KDa bands of tachyzoites, respectively. It was identified that 15 KDa protein in bradyzoite, which was not a glycoprotein, was a major membrane protein with sufficient antigenicity, and in the case of tacky- zoite, 52 KDa surface glycoprotein (gp52) with specific antigenicity might be added to the major surface protein, p30.

• Journal of Ginseng Research
• /
• v.44 no.5
• /
• pp.704-716
• /
• 2020

Background: Ginsenoside Rh2 (GRh2) is a characterized component in red ginseng widely used in Korea and China. GRh2 exhibits a wide range of pharmacological activities, such as anti-inflammatory, antioxidant, and anticancer properties. However, its effects on Toxoplasma gondii (T. gondii) infection have not been clarified yet. Methods: The effect of GRh2 against T. gondii was assessed under in vitro and in vivo experiments. The BV2 cells were infected with tachyzoites of T. gondii RH strain, and the effects of GRh2 were evaluated by MTT assay, morphological observations, immunofluorescence staining, a trypan blue exclusion assay, reverse transcription PCR, and Western blot analyses. The in vivo experiment was conducted with BALB/c mice inoculated with lethal amounts of tachyzoites with or without GRh2 treatment. Results and conclusion: The GRh2 treatment significantly inhibited the proliferation of T. gondii under in vitro and in vivo studies. Furthermore, GRh2 blocked the activation of microglia and specifically decreased the release of inflammatory mediators in response to T. gondii infection through TLR4/NF-κB signaling pathway. In mice, GRh2 conferred modest protection from a lethal dose of T. gondii. After the treatment, the proliferation of tachyzoites in the peritoneal cavity of infected mice markedly decreased. Moreover, GRh2 also significantly decreased the T. gondii burden in mouse brain tissues. These findings indicate that GRh2 exhibits an antieT. gondii effect and inhibits the microglial activation through TLR4/NF-κB signaling pathway, providing the basic pharmacological basis for the development of new drugs to treat toxoplasmic encephalitis.

• Parasites, Hosts and Diseases
• /
• v.54 no.2
• /
• pp.139-145
• /
• 2016

Toxoplasmosis is a serious disease caused by Toxoplasma gondii, one of the most widespread parasites in the world. Lipid metabolism is important in the intracellular stage of T. gondii. Stearoyl-CoA desaturase (SCD), a key enzyme for the synthesis of unsaturated fatty acid is predicted to exist in T. gondii. Sterculic acid has been shown to specifically inhibit SCD activity. Here, we examined whether sterculic acid and its methyl ester analogues exhibit anti-T. gondii effects in vitro. T. gondii-infected Vero cells were disintegrated at 36 hr because of the propagation and egress of intracellular tachyzoites. All test compounds inhibited tachyzoite propagation and egress, reducing the number of ruptured Vero cells by the parasites. Sterculic acid and the methyl esters also inhibited replication of intracellular tachyzoites in HFF cells. Among the test compounds, sterculic acid showed the most potent activity against T. gondii, with an $EC_{50}$ value of $36.2{\mu}M$, compared with $EC_{50}$ values of $248-428{\mu}M$ for the methyl esters. Our study demonstrated that sterculic acid and its analogues are effective in inhibition of T. gondii growth in vitro, suggesting that these compounds or analogues targeting SCD could be effective agents for the treatment of toxoplasmosis.