[Show abstract][Hide abstract] ABSTRACT: Background:
Plasmodium falciparum malaria is a significant public health problem in Comoros, and artemisinin combination therapy (ACT) remains the first choice for treating acute uncomplicated P. falciparum. The emergence and spread of artemisinin-resistant P. falciparum in Southeast Asia, associated with mutations in K13-propeller gene, poses a potential threat to ACT efficacy. Detection of mutations in the P. falciparum K13-propeller gene may provide the first-hand information on changes in parasite susceptibility to artemisinin. The objective of this study is to determinate the prevalence of mutant K13-propeller gene among the P. falciparum isolates collected from Grande Comore Island, Union of Comoros, where ACT has been in use since 2004.
A total of 207 P. falciparum clinical isolates were collected from the island during March 2006 and October 2007 (n = 118) and March 2013 and December 2014 (n = 89). All isolates were analysed for single nucleotide polymorphisms (SNPs) and haplotypes in the K13-propeller gene using nested PCR and DNA sequencing.
Only three 2006-2007 samples carried SNPs in the K13-propeller gene, one having a synonymous (G538G) and the other having two non-synonymous (S477Y and D584E) substitutions leading to two mutated haplotypes (2.2 %, 2/95). Three synonymous mutations (R471R, Y500Y, and G538G) (5.9 %, 5/85) and 7 non-synonymous substitutions (21.2 %, 18/85) with nine mutated haplotypes (18.8 %, 16/85) were found in isolates from 2013 to 2014. However, none of the polymorphisms associated with artemisinin-resistance in Southeast Asia was detected from any of the parasites examined.
This study showed increased K13-propeller gene diversity among P. falciparum populations on the Island over the course of 8 years (2006-2014). Nevertheless, none of the polymorphisms known to be associated with artemisinin resistance in Asia was detected in the parasite populations examined. Our data suggest that P. falciparum populations in Grande Comore are still effectively susceptible to artemisinin. Our results provide insights into P. falciparum populations regarding mutations in the gene associated with artemisinin resistance and will be useful for developing and updating anti-malarial guidance in Comoros.
Preview · Article · Dec 2015 · Parasites & Vectors
[Show abstract][Hide abstract] ABSTRACT: Malaria is the most relevant parasitic disease worldwide, and severe malaria is characterized by cerebral edema, acute lung injury (ALI), and multiple organ dysfunctions; however, the mechanisms of lung damage need to be better clarified. In this study, we used Kunming outbred mice infected with Plasmodium berghei ANKA (PbANKA) to elucidate the profiles of T cell immunoglobulin and mucin domain-3 (Tim-3) and its ligand galecin-9 (Gal-9) in the development of ALI. Mice were injected intraperitoneally with 10(6) PbANKA-infected red blood cells. The lungs and mediastinal lymph nodes (MLNs) were harvested at days 5, 10, 15, and 20 post infections (p.i.). The grade of lung injury was histopathologically evaluated. Tim-3- and Gal-9-positive cells in the lungs and MLNs were stained by immunohistochemistry, and the messenger RNA (mRNA) expressions of Tim-3, Gal-9, and related cytokines were assessed using quantitative real-time polymerase chain reaction (qRT-PCR). Bronchoalveolar lavage fluid (BALF) analyses were performed from days 18 to 20 p.i. The results showed that the pathological severities in the lungs were increased with times and the total protein level in the BALFs was significantly elevated in PbANKA-infected mice. The numbers of Gal-9(+) and Tim-3(+) cells in the lungs were significantly increased, and the mRNA levels of both Gal-9 and Tim-3 in the lungs and MLNs were over-expressed in PbANKA-infected mice. In conclusion, our data suggested that Tim-3/Gal-9 may play a role in PbANKA-induced ALI.
No preview · Article · Oct 2015 · Parasitology Research
[Show abstract][Hide abstract] ABSTRACT: Malaria has been one of the most devastating tropical parasite infectious diseases popular around the world. Severe malaria is characterized by multiple organ dysfunctions, especially liver damage. However, the mechanisms of malarial liver injury remain to be better clarified. In this study, Kunming mice inoculated intraperitoneally (i.p.) with 10(6) Plasmodium berghei ANKA (PbANKA)-infected red blood cells (iRBCs) were investigated at days 5, 10, 15, and 20 post-infection (p.i.) to elucidate the profiles of T-cell immunoglobulin and mucin domain-3 (Tim-3) and its ligand galecin-9 (Gal-9) in the development of liver injury. The histopathology of livers and spleens from PbANKA-infected mice were observed, the parasite burdens of the livers and spleens using quantitative real-time PCR (qRT-PCR), Tim-3- and Gal-9-positive cells in the livers and spleens using immunohistochemical staining, and the mRNA levels of Tim-3, Gal-9, and cytokines in both the livers and spleens using qRT-PCR were examined. Our results showed that parasite burdens in the livers and spleens were significantly increased with time after PbANKA infection. Histological scores of both the liver and spleen tissues were significantly increased with time; the numbers of Tim-3- and Gal-9-positive cells were significantly increased in both the livers and spleens using immunohistochemical staining, and the mRNA levels of Tim-3 and Gal-9 in the livers and spleens were also significantly increased after infection. Our data suggests that the increase of Tim-3/Gal-9 expressions may play an important role in the liver damage during P. berghei infection.
No preview · Article · Oct 2015 · Parasitology Research
[Show abstract][Hide abstract] ABSTRACT: The immunoinhibitory receptor T cell immunoglobulin domain and mucin domain-1 (Tim-1) and Tim-3 participate in the regulation of Th immune response as well as innate immunity. However, there is no report about the expression of Tim genes in Toxoplasma gondii-infected experimental models during pregnancy. In this study, Kunming outbred pregnant mice were infected with RH strain of T. gondii through vagina at days 10 to 16 of gestation, and the mRNA expressions of Tim-1, Tim-3, interleukin (IL)-4, and interferon (IFN)-γ in the placentas, uteri, and draining lumber aortic lymph nodes (LALNs) at day 18 of gestation were analyzed using quantitative real-time PCR (qRT-PCR). Compared with uninfected pregnant controls, significantly increased levels of IFN-γ and Tim-3 were detected in the placentas (P < 0.001), uteri (P = 0.003 and P = 0.017, respectively), and LALNs (P = 0.003 and P = 0.025, respectively) of T. gondii-infected mice; there were positive and significant correlations between Tim-3 and IFN-γ mRNA expression levels in the placentas (R
2 = 0.6331, P = 0.0011), uteri (R
2 = 0.5658, P = 0.003), and LALNs (R
2 = 0.5583, P = 0.0033) of infected mice. Tim-1 (P = 0.002) and IL-4 (P = 0.003) expressions were significantly increased in the placentas, but Tim-1 were significantly decreased in the uteri (P = 0.013) and LALNs (P < 0.001) of infected pregnant mice in comparison of uninfected pregnant controls. Our data suggested that Tim-3 may play a regulatory role in T. gondii-infected pregnant mouse model.
No preview · Article · Oct 2014 · Parasitology Research
[Show abstract][Hide abstract] ABSTRACT: Background: Plasmodium vivax is the predominant species of human malaria parasites present in China. Although sulphadoxine-pyrimethamine (SP) and chloroquine (CQ) have been widely used for malaria treatment in China, the resistance profiles of these drugs are not available. Analysis of dihydrofolate reductase (dhfr), dihydropteroate synthase (dhps), and multidrug resistance (mdr-1) gene mutations in P. vivax isolates is a valuable molecular approach for mapping resistance to SP and CQ. This study investigates the prevalence of pvdhfr, pvdhps, and pvmdr-1 of P. vivax clinical isolates from China and provides baseline molecular epidemiologic data on SP- and CQ-associated resistance in P. vivax.
[Show abstract][Hide abstract] ABSTRACT: Toxoplasma gondii can establish chronic infection and is characterized by the formation of tissue cysts in the brain. Although T. gondii can infect any kind of nucleated cells, macrophages and related mononuclear phagocytes are its preferred targets in vivo. Microglial cells are the resident macrophages in the central nervous system. It has been reported that CD37, a tetraspanin molecule, is expressed exclusively in the immune system; Dectin-1, an important pattern-recognition receptor, is expressed on the surface of murine primary microglia. The Dectin-1-CD37 association can affect Dectin-1-mediated IL-6 secretion. However, there is no report concerning the relationship among the expressions of Dectin-1, IL-6, and CD37 during T. gondii infection. In the present study, Kunming outbred mice were infected with Prugniaud (Pru), a type II strain of T. gondii by oral gavage, and BV-2 murine microglial cells were cocultured with RH tachyzoites of T. gondii. By H&E and immunohistochemical staining, the results showed that marked inflammation and a significantly increased activation of Iba1-positive microglial cells were observed in the brain tissues of mice infected with T. gondii Pru strain at 5 weeks postinfection (p.i.) in comparison of uninfected controls. Using quantitative real-time PCR detection, Dectin-1 messenger RNA (mRNA) expressions were significantly upregulated in both brains at 3 (P < 0.01), 5 (P < 0.01), 7 (P < 0.01), and 9 (P < 0.05) weeks p.i. and spleens at 3, 5, 7, and 9 weeks p.i. (P < 0.01). IL-6 expressions showed similar dynamic tendency as that of Dectin-1 in both the brains and spleens at the same times in comparison of uninfected controls; CD37 expressions were significantly increased in the brain tissues at all the times (P < 0.01) and no significant differences in the spleens at 3 weeks p.i. but significantly downregulated in the spleens at 5, 7, and 9 weeks p.i. (P < 0.01). In vitro study showed that compared with uninfected controls, the mRNA expressions of Dectin-1 at 2, 4, 8, and 10 h (P < 0.01); IL-6 at 8 and 10 h (P < 0.01); and CD37 at 4 (P < 0.05), 8 (P < 0.01), and 10 h (P < 0.01) were significantly upregulated in BV-2 murine microglial cells stimulated with RH tachyzoites of T. gondii. Our data suggested that the expression of Dectin-1 was positively correlated with that of IL-6 in toxoplasmic encephalitis (TE) mouse model; Dectin-1 interaction with tetraspanin CD37 regulated IL-6 expression in both the brain tissues of TE mouse model and in the T. gongdii-infected BV-2 murine microglial cells.
No preview · Article · May 2014 · Parasitology Research
[Show abstract][Hide abstract] ABSTRACT: Mast cells (MCs) are implicated in the pathogenesis of allergic reactions and inflammatory conditions through the release of inflammatory mediators. So far limited attention has been given to the role of MCs in periodontitis. T cell immunoglobulin mucin domain (TIM)-3 is an immunomodulatory molecule and influences MC function. However, whether TIM-3 is expressed on MCs in the process of human periodontal disease has not been reported. Therefore, we identified MCs by toluidine blue staining and examined the expression of TIM-3 on tryptase-positive MCs in different severities of human chronic periodontitis using double-immunofluorescence staining in this study.
No preview · Article · Apr 2014 · Archives of oral biology
[Show abstract][Hide abstract] ABSTRACT: T cells and IFN-γ are essential for controlling the reactivation of toxoplasmic encephalitis (TE), regardless of whether mice are susceptible or resistant to TE. It has been demonstrated that CD8(+) T cells exhausted in chronic Toxoplasma gondii infection result in TE reactivation in C57BL/6 mice. However, this phenomenon had not been reported in genetically TE-resistant BALB/c mice. To explore the immune mechanism of TE in different backgrounds of mice, the dynamic expressions of Tim-3, programmed cell death 1 (PD-1), and their ligands (galectin-9, PD-L1, PD-L2) in brain tissues were compared between TE-resistant BALB/c and -susceptible C57BL/6 mice infected with Prugniaud (Pru, a type II strain) of T. gondii in this study. Compared with infected BALB/c mice, there were remarkable pathological changes with significantly higher histological scores in the brains of C57BL/6 mice at 14, 35, 50, and 70 days postinfection (p.i., P < 0.01); significantly increased mRNA expressions of Tim-3 at 35 (P < 0.05) and 70 (P < 0.01) days p.i.; and significantly increased PD-1 at all the times p.i. (P < 0.01) in the brains of infected C57BL/6 mice. Furthermore, there were significantly increased mRNA expressions of PD-L1 in the brain of C57BL/6 mice than that in BALB/c mice at all the times p.i. (P < 0.01). Although the mRNA expressions of galectin-9 (ligand of Tim-3) were increased in the brains of both lineages of mice at all the times p.i., it showed no differences between the two lineages of mice. Our data suggest that the differences of Tim-3 and PD-1/PD-L1 expressions may contribute to the different immune responses between TE-resistant BALB/c and -susceptible C57BL/6 mice infected with Pru strain of T. gondii.
No preview · Article · Jan 2014 · Parasitology Research
[Show abstract][Hide abstract] ABSTRACT: Although the numbers of malaria cases in China have been declining in recent years, outbreaks of Plasmodium vivax malaria were still being reported in rural areas south of the Yellow River. To better understand the transmission dynamics of P. vivax parasites in China, the extent of genetic diversity of P. vivax populations circulating in Bozhou of Anhui province of China were investigated using three polymorphic genetic markers: merozoite surface proteins 1 and 3alpha (pvmsp-1 and pvmsp-3alpha) and circumsporozoite protein (pvcsp).
Forty-five P. vivax clinical isolates from Bouzhou of Anhui province were collected from 2009 to 2010 and were analysed using PCR/RFLP or DNA sequencing.
Seven and six distinct allelic variants were identified using PCR/RFLP analysis of pvmsp-3alpha with HhaI and AluI, respectively. DNA sequence analysis of pvmsp-1 (variable block 5) revealed that there were Sal-I and recombinant types but not Belem type, and seven distinct allelic variants in pvmsp-1 were detected, with recombinant subtype 2 (R2) being predominant (66.7%). All the isolates carried pvcsp with VK210 type but not VK247 or P. vivax-like types in the samples. Sequence analysis of pvcsp gene revealed 12 distinct allelic variants, with VK210-1 being predominant (41.5%).
The present data indicate that there is some degree of genetic diversity among P. vivax populations in Anhui province of China. The genetic data obtained may assist in the surveillance of P. vivax infection in endemic areas or in tracking potential future disease outbreak.
[Show abstract][Hide abstract] ABSTRACT: Background/purpose
A medicinal herb Scutellaria baicalensis Georgi has been reported to possess antibacterial and anti-inflammatory activities. In this study, the effect of aqueous extracts obtained from S. baicalensis GEORGI (SbE) on the immune response in ligature-induced periodontitis of mouse models was investigated.
Materials and methods
Sixty mice were randomly divided into four groups. Experimental periodontitis was induced by wrapping Porphyromonas gingivalis-soaked silk ligature at the gingival margins of the left first maxillary molar, and some of them were treated with SbE from the 4th week after the ligature. There were also normal and SbE-treated controls without ligature. The histopathologic analyses of periodontia were performed at Weeks 4, 6, 8, and 10 after the ligature. Serum levels of immunoglobulin (Ig) G isotypes, e.g., IgG1 and IgG2a, were quantified by enzyme-linked immunosorbent assay.
Compared with the experimental periodontitis group, the periodontitis + SbE-treated mice showed significantly improved histopathology of periodontal tissue at Weeks 6, 8, and 10 after the ligature (P < 0.05). Compared with the control groups, periodontitis + SbE-treated mice exhibited significant higher levels of Th2-type IgG1 at Weeks 6, 8, and 10 (P < 0.01), whereas levels of the Th1-type IgG2a were relatively unaffected in periodontitis + SbE-treatment group but significantly increased in experimental periodontitis group at Weeks 6, 8, and 10 (P < 0.01).
Our data suggest that the aqueous extract of S. baicalensis Georgi could improve the experimental periodontitis in mouse model by inducing a Th2-polarized immune response.
No preview · Article · Dec 2013 · Journal of dental sciences
[Show abstract][Hide abstract] ABSTRACT: The role of mast cells (MCs) in Toxoplasma gondii infection is poorly known. Kunming outbred mice were infected intraperitoneally with RH strain T. gondii, either treated with compound 48/80 (C48/80, MC activator) or disodium cromoglycate (DSCG, MC inhibitor). Compared with infected controls, infected mice treated with C48/80 exhibited significantly increased inflammation in the liver (P < 0.01), spleen (P < 0.05), and mesentery (P < 0.05) tissues, higher parasite burden in the peritoneal lavage fluids (P < 0.01), and increased levels of mRNA transcripts of T. gondii tachyzoite surface antigen 1 (SAG1) gene in the spleen and liver tissues (P < 0.01), accompanied with significantly increased Th1 cytokine (IFN-γ, IL-12p40, and TNF-α) (P < 0.01) and decreased IL-10 (P < 0.01) mRNA expressions in the liver, and increased IFN-γ (P < 0.01) and IL-12p40 (P < 0.01) but decreased TNF-α (P < 0.01) and IL-4 (P < 0.01) in the spleens of infected mice treated with C48/80 at day 9-10 p.i. Whereas mice treated with DSCG had significantly decreased tissue lesions (P < 0.01), lower parasite burden in the peritoneal lavage fluids (P < 0.01) and decreased SAG1 expressions in the spleen and liver tissues (P < 0.01), accompanied with significantly increased IFN-γ (P < 0.01) and IL-12p40 (P < 0.05) in the liver, and decreased IFN-γ (P < 0.05) and TNF-α (P < 0.01) in the spleens; IL-4 and IL-10 expressions in both the spleen and liver were significantly increased (P < 0.01) in the infected mice treated with DSCG. These findings suggest that mediators associated with the MC activation may play an important role in modulating acute inflammatory pathogenesis and parasite clearance during T. gondii infection in this strain of mice. Thus, MC activation/inhibition mechanisms are potential novel targets for the prevention and control of T. gondii infection.
[Show abstract][Hide abstract] ABSTRACT: Concomitant infections of different species of parasites are common in the field. Infection with one parasite species likely triggers host responses that may influence the subsequent infection of another species and alter disease outcomes. So far, the majority of studies have focused on single species parasite infection, and the mechanisms of protection induced by the first parasite infection against the secondary infection remain poorly defined. In this study, we assess the impact of trematode Clonorchis sinensis infection on the course of another tissue nematode Trichinella spiralis challenge. We observed that mice with preexisting C. sinensis infection had lower worm burden of intestinal T. spiralis than those infected with T. spiralis alone; mice with preexisting C. sinensis also had severe enteric histopathological changes and higher counts of intestinal Paneth cells in responses to T. spiralis challenge. The mRNA levels of interleukin (IL)-4, IL-10, IL-13, and tumor necrosis factor (TNF)-α from the small intestine and spleen of the different groups were analyzed using quantitative real-time polymerase chain reaction. Compared with that in mice infected with T. spiralis alone, the mRNA expression of IL-13 was significantly increased in the small intestine tissues and IL-4, IL-13, and TNF-α were significantly increased in the spleen tissues in the dually infected mice. Our findings suggest that a "preexisting" trematode infection of C. sinensis is a factor which contributes to reducing the establishment of T. spiralis adult worms in the small intestine.
No preview · Article · Jul 2013 · Parasitology Research
[Show abstract][Hide abstract] ABSTRACT: The current anti-Toxoplasma gondii drugs have many shortcomings and effective vaccines against T. gondii may contribute to the control of this pathogen. Pidotimod is a synthetic substance capable of stimulating both cellular and humoral immunity. To investigate the possible adjuvant effect of pidotimod on the immune response to T. gondii in Kunming mice induced by ultraviolet-attenuated T. gondii (UV-T.g), in this study, mice were immunized intraperitoneal (i.p.) with UV-T.g or UV-T.g co-administered with pidotimod (UV-T.g + PT). After infection or challenge by i.p. injection of 10(2) RH tachyzoites, the animal survival rate, parasite burden in peritoneal lavage fluids, liver histopathology, the level of serum anti-toxoplasma IgG antibody, and the mRNA expressions of IL-2, IFN-γ, and TNF-α from spleen analyzed using real-time PCR, were compared among different groups. The results showed that, compared with infected controls, infected mice treated with pidotimod had significantly increased survival rate and extended survival time, decreased parasite burden, improved liver histopathology, increased level of anti-toxoplasma IgG antibody, and increased mRNA expressions of Th1-type cytokine (IL-2, IFN-γ, and TNF-α) (P < 0.01), while mice vaccinated with UV-T.g and then challenged had even significantly increased survival rate and extended survival time, decreased parasite burden, improved liver histopathology, and increased mRNA expressions of Th1-type cytokines (IL-2, IFN-γ, and TNF-α) (P < 0.01); furthermore, vaccinated mice co-administered with pidotimod had even more lower parasite burden, milder liver histopathology, and higher levels of Th1-type cytokine and anti-toxoplasma IgG antibody (P < 0.01). Our data demonstrated that pidotimod in vivo could promote strong and specific humoral and cellular immune response to T. gondii challenge infection when co-administered with UV-attenuated T. gondii. It suggests that pidotimod may have the potential to be used as an effective vaccine adjuvant.
No preview · Article · Jun 2013 · Parasitology Research
[Show abstract][Hide abstract] ABSTRACT: Toxoplasmic encephalitis (TE) is one of the most common central nervous system (CNS) opportunistic infections in HIV-infected patients. It can be prevented and treated through drug regimen. However, drugs have serious adverse effects sometimes. The purpose of this review is to determine the most effective therapy for TE in HIV-infected patients. Different primary prophylaxis and treatment regimens have been compared with regard to episodes of TE, clinical response, morbidity, and serious adverse events. In September 2012, we searched PubMed, Google Scholar, EMBASE, and CENTRAL (the Cochrane Central Register of Controlled Trials) database for randomized and quasi-randomized controlled trials of any drug regimen for primary prophylaxis and treatment of TE in HIV-infected patients. We independently extracted data and assessed eligibility and risk of bias using a standardized data collection form, and resolved any disagreement through discussion. We combined dichotomous outcomes using odds ratio (OR), presenting with 95% confidence interval (CI). Eleven trials were found to meet the inclusion criteria. Six trials compared trimethoprim-sulfamethoxazole (TMP-SMX) with dapsone-pyrimethamine (D-P) were analyzed together for the outcome of episodes of TE, morbidity, and serious adverse events. The two treatment arms did not differ for episodes of TE (OR=0.98; 95% CI: 0.48-2.00). Compared with D-P, TMP-SMX showed a beneficial trend in terms of mortality despite a lack of statistical significance (OR=0.75; 95% CI: 0.53-1.06). However, TMP-SMX is still associated with substantial toxicity and intolerance (OR=1.47; 95% CI: 0.91-2.38). Three trials compared pyrimethamine-sulfadiazine (P-S) with pyrimethamine-clindamycin (P-C) were analyzed together for the outcome of clinical response, morbidity, and serious adverse events. Compared with P-C, P-S showed a beneficial trend in terms of clinical response (OR=1.63; 95% CI: 1.05-2.51); P-S also showed a beneficial trend in terms of mortality despite a lack of statistical significance (OR=0.66; 95% CI: 0.37-1.17). However, P-S is still associated with substantial toxicity and intolerance (OR=3.08; 95% CI: 1.82-5.24). Two trials compared P-S with TMP-SMX were analyzed together for the outcome of clinical response, morbidity, and serious adverse events. The two treatment arms did not differ for clinical response (OR=0.90; 95% CI: 0.39-2.06). Compared with TMP-SMX, P-S showed a beneficial trend in terms of mortality despite a lack of statistical significance (OR=0.12; 95% CI: 0.01-1.39). However, P-S is still associated with substantial toxicity and intolerance (OR=2.91; 95% CI: 0.99-8.55). The available evidence fails to identify any one superior regimen for the primary prophylaxis and treatment of TE. The choice of therapy will often be directed by available therapy. Although current evidence does not allow a definitive recommendation, administration of TMP-SMX for primary prophylaxis and treatment of TE in patients with HIV infection is consistent with the available data.
[Show abstract][Hide abstract] ABSTRACT: Cerebral malaria (CM) is a serious and often fatal complication of Plasmodium falciparum infections; however, the precise mechanisms leading to CM is poorly understood. Mouse malaria models have provided insight into the key events in pathogenesis of CM. T-cell immune response is known to play an important role in malaria infection, and members of the T-cell immunoglobulin- and mucin-domain-containing molecule (Tim) family have roles in T-cell-mediated immune responses. Tim-1 and Tim-3 are expressed on terminally differentiated Th2 and Th1 cells, respectively, and participate in the regulation of Th immune response. Until now, the role of Tim family proteins in Plasmodium infection remains unclear. In the present study, the mRNA levels of Tim-1, Tim-3, and some key Th1 and Th2 cytokines in the spleen of Kunming outbred mice infected with Plasmodium berghei ANKA (PbANKA) were determined using real-time polymerase chain reaction (qRT-PCR). Compared with uninfected controls, Tim-1 expression was significantly decreased in infected mice with CM at day 10 postinfection (p.i.) but significantly increased in infected mice with non-CM at day 22 p.i.; in contrast, Tim-3 expression was significantly increased in infected mice both with CM at day 10 p.i. and with non-CM at day 22 p.i. The expressions of IFN-γ, TNF-α, IL-10, and IL-12 were significantly increased but IL-4 was significantly decreased in infected mice with CM at days 10 p.i., whereas the expressions of IFN-γ, TNF-α, IL-4, IL-10, and TGF-β were significantly increased but IL-12 was significantly decreased in infected mice with non-CM at days 22 p.i. Furthermore, the expression of Tim-1 and Tim-3 could reflect Th2 and Th1 immune response in the spleen of PbANKA-infected mice, respectively. Our data suggest that PbANKA infection could inhibit the differentiation of T lymphocytes toward Th2 cells, promote the Th1 cell differentiation, and induce Th1-biased immune response in the early infective stage, whereas the infection could promote Th2 cell differentiation and induce Th2-biased immune response in the late infective stage. Our data indicate that both Tim-1 and Tim-3 may play a role in the process of PbANKA infection, which may represent a potential therapeutic target.
No preview · Article · May 2013 · Parasitology Research
[Show abstract][Hide abstract] ABSTRACT: Toxoplasma gondii can establish chronic infection and is characterized by the formation of tissue cysts in the brain. The cysts may remain throughout the life of the host but can reactivate and cause life-threatening toxoplasmic encephalitis (TE) in immunocompromised patients. T cell-mediated immune responses are essential for preventing the reactivation of chronic infection of T. gondii in the brain. The immunoinhibitory receptor T cell immunoglobulin and mucin domain (Tim)-1 and Tim-3 are expressed on terminally differentiated T helper (Th) 2 and Th1 cells, respectively, participating in the regulation of Th immune response. However, there is no report concerning the role of Tim genes in TE. In this study, Kunming outbred mice were infected with Prugniaud (Pru), a type II strain of T. gondii by oral gavage. Compared with the uninfected controls, there were mild brain inflammations at 3 weeks postinfection (p.i.), moderate brain inflammations at 5 weeks p.i., and aggravated brain inflammations and necrosis at 7 and 9 weeks p.i. The expressions of tachyzoite stage-specific genes in brains were consistent with the severity of brain histopathology of TE at 5 and 7 weeks p.i., while the expressions of bradyzoite stage-specific genes in brains were significantly increased at 7 and 9 weeks p.i. Using quantitative real-time PCR detection and immunohistochemistry staining, our results showed that the expressions of Tim-3 were significantly upregulated in both brains and spleens at 5 weeks p.i. and in spleens at 9 weeks p.i., which showed the similar dynamic tendency as that of interferon-γ expressions in both brains and spleens at the same times. In contrast, the Th2-specific marker Tim-1 expressions were significantly downregulated in both brains and spleens at 3 weeks p.i. and upregulated in both brains and spleens at 7 and 9 weeks p.i., which showed the similar dynamic tendency as that of interleukin-4 expressions in both brains and spleens at the same time. Our data indicate that Tim-3 may involve in the process of TE in mice infected with T. gondii Pru strain.
No preview · Article · Apr 2013 · Parasitology Research
[Show abstract][Hide abstract] ABSTRACT: Laboratory maintenance of the RH strain of Toxoplasma gondii is generally done by passage in mice, in vitro propagation in fibroblasts, or cryopreservation of peritoneal exudates from mice infected with T. gondii. To explore alternative techniques for preserving laboratory T. gondii tachyzoites, we propose a new method of freezing tissues from infected mice. The effect of storage of T. gondii tissue tachyzoites in two different cryoprotectant combinations and at two different temperatures was studied. The liver and spleen tissues, and peritoneal exudates from mice infected with RH-GFP strain of T. gondii, suspended in RPMI 1640 medium supplemented with 12 % glycerol plus 20 % calf serum, or 12 % dimethyl sulfoxide (DMSO) plus 20 % calf serum, were stored for 3 months at -20 °C in an ordinary refrigerator or at -80 °C in a deep freezer, respectively. The viability of tissue T. gondii tachyzoites was determined by animal inoculation method, which was assessed by monitoring survival and tissue parasitemia in recipient mice. Our data showed that toxoplasma tachyzoites in the above tissues remained viable after cryopreservation in 12 % DMSO plus 20 % calf serum at -80 °C, the infectivity of tachyzoites from the tissues and peritoneal fluids was demonstrated in inoculated murine tissues. Our data indicate that freezing infected murine tissues at -80 °C provides a simple and appropriate method for preservation of T. gondii tachyzoites in laboratory without the need for costly liquid nitrogen preservation procedures.
No preview · Article · Jun 2012 · Parasitology Research
[Show abstract][Hide abstract] ABSTRACT: Background: Mast cells are tissue resident immune cells that participate in a variety of allergic and inflammatory conditions. Limited attention has been given to the role of mast cells in periodontal diseases, and the effects of mast cell degranulation on the chronic stages of non-allergic inflammation, particularly in periodontitis, are not known. The present study was undertaken to analyze the relationship between the mast cell degranulation and human periodontal disease progression. Methods: A total of 50 clinical specimens included moderate periodontitis (n=17), advanced periodontitis (n=18), and healthy control tissues (n=15) were involved in this study. All specimens were fixed in 10% buffered formalin, stained with hematoxylin and eosin for histopathology, with toluidine blue for identifying mast cells, and by immunohistochemistry for the expressions of mast cell tryptase in periodontal tissues. The total and degranulated mast cell densities (per high-power field) were quantified in the specimens. Results: Compared to healthy controls, there were significantly increased both total and degranulated mast cell densities in human moderate (P<0.01) and advanced periodontitis groups (P<0.01) by toluidine blue staining; and there were significantly higher densities of both total and degranulated tryptase-positive mast cell subpopulation in moderate (P<0.01) and even significantly higher subpopulation densities in advanced periodontitis group by immunohistochemical staining, in which both total and degranulated mast cell densities were significantly higher in advanced periodontitis group than those in moderate periodontitis group (P<0.01) by both toluidine blue staining and immunohistochemical staining. There were significantly severer periodontal inflammatory pathology in advanced periodontitis group than those in moderate periodontitis group (P<0.01). Conclusion: These findings indicate a significant correlation between tryptase-positive mast cell density, the degree of their degranulation, and the human periodontitis severity, and our results further indicate that mast cell degranulation appears to be associated with human periodontal disease.
No preview · Article · Apr 2012 · Journal of Periodontology
[Show abstract][Hide abstract] ABSTRACT: Toxoplasma gondii is a parasite that infects animals and humans worldwide. The standard treatment for toxoplasmosis is limiting due to toxic adverse effects, thus there is a need to identify new drugs that are less toxic. Both Astragalus membranaceus and Scutellaria baicalensis GEORGI are popular traditional Chinese herbs widely used for the treatment of various inflammatory diseases in Asia, and we have previously demonstrated that water extracts of A. membranaceus (AmE) and S. baicalensis GEORGI (SbE) have good efficacy in controlling T. gondii replication in mouse models. This study was designed to further evaluate their effects against developing tachyzoites of the RH strain of T. gondii in HeLa cell cultures. AmE, SbE, and TMP-SMX (trimethoprim-sulfamethoxazole) were added into the wells containing both HeLa cells and replicating T. gondii of green fluorescent protein (GFP)-expressing RH tachyzoites. The proliferation and morphous of the tachyzoites were observed, the fluorescence intensity expressed as the fluorescence gray scale value was measured, and the living tachyzoites were counted at different culture times after treatment. The results showed that, compared to untreated controls, parasites treated with either AmE or SbE had significantly decreased intracellular replication at 72, 96, and 120 h after treatment (P < 0.01); while compared to either AmE- or SbE-treated groups, SMX-treated groups had even significantly decreased replication (only a few living parasites were detected) at the above times (P < 0.01). Our data demonstrated that both AmE and SbE had remarkable in vitro activities against T. gondii.
No preview · Article · Dec 2011 · Parasitology Research
[Show abstract][Hide abstract] ABSTRACT: Studies have shown that psychologic stress plays a significant role in the outcome of many diseases. The present study is designed to investigate the effect of stress on experimental ligature-induced periodontal disease in rats by means of a variable moderate chronic stress model.
Sixty-six age-matched male Wistar rats of specific pathogen-free grade were randomly divided into four groups: 1) normal control group, naive rats; 2) experimental periodontitis group, received only silk ligatures at the gingival margins of the second maxillary molar; 3) stress-stimulation group, treated only with experimental stress conditions; and 4) experimental periodontitis plus stress-stimulation group (e.g., experimental groups also exposed to stress). Stress was imposed by means of restraint stress, cold-water immersion stress, and cat shock stress, which were all applied randomly. The rats were sacrificed at weeks 1, 4, 6, and 8 of the experiment. Attachment losses (AL) were measured by a specially made periodontal probe. The histopathologic changes of periodontia stained with hematoxylin and eosin were observed under a microscope. The expression of hypoxia-inducible factor-1α used to evaluate tissue hypoxic degree in periodontal tissues was tested by immunohistochemistry.
Our results show that there was no significant difference of AL among the normal control and the stress-stimulation groups (P >0.05); AL of the periodontitis plus stress-stimulation group was significantly higher than that of the experimental periodontitis group at weeks 4, 6, and 8 (P <0.01), and the hypoxia-inducible factor-1α expression scores of the periodontitis plus stress-stimulation group were significantly higher than those of the experimental periodontitis group at weeks 4, 6, and 8 (P = 0.0477).
Stress-stimulation may aggravate periodontitis by decreased tissue oxygenation in rats. We conclude that there is a correlation of periodontitis severity with psychologic stress and periodontal tissue hypoxia.
No preview · Article · Dec 2010 · Journal of Periodontology