Assessment of the oxidative status and goblet cell response during eimeriosis and after treatment of mice with magnesium oxide nanoparticles

Magnesium nanoparticles have been the focus of study over the past few years because of its functionality in the body. Assessment of the impact of magnesium oxide nanoparticles (MgNPs) on eimeriosis has yet to be conducted. The goal of this study was to see how MgNPs affected the parasite Eimeria papillata infected jejunum. To induce eimeriosis, mice were infected with sporulated oocysts. For treatment, 5 mg / Kg MgNPs was used for 5 consecutive days. The infection reduced the number of intestinal goblet cells and their associated genes MUC2 and MUC4, as well as increasing oxidative damage in the jejunum. MgNPs significantly reduced the oocyst production in the feces by about 77 %. After treatment, the number of goblet cells per villus increased from 4.17% to 7.40.6%. Moreover, the MgNPs were able to upregulate the expression of MUC2 and MUC4-mRNA. MgNPs significantly increased the activity of catalase and superoxide dismutase, as well as the extent of glutathione, by day 5 after infection with the parasite. On contrary, MgNPs decreased the level of malondialdehyde and nitric oxide. The findings suggested that MgNPs could be an effective anti-eimeriosis agent due to their anti-eimerial and anti-oxidant roles, as well as the regulatory effect on the goblet cell mucin genes in the jejunum of mice.     

Trichinella spiralis: enteric mucin-related response to experimental infection in conventional and SPF pigs

Duodenal and jejunal responses to infection with Trichinella spiralis were compared in weaned piglets with a "normal dirty" vs. a "clean SPF" gut flora. Histochemical staining of neutral, acidic, sialylated, and sulphated residues was used to assess biosynthetic responses in mucin-secreting goblet cells. Peanut and Ulex lectins were also used to assess responses within the intestinal glycocalyx. Histomorphometric analysis was undertaken to evaluate the distribution and staining patterns of goblet cells in villi and crypts. Our analysis showed that stored mucin within goblet cells increased more in the infected conventional animals than in the infected SPF group. This was accompanied by changes in the pattern of sulphation and sialylation in the duodenum and jejunum. The thickness of the glycocalyx was increased in both duodenum and jejunum in both infected groups. However, this effect was greater for the infected SPF animals than the infected conventional animals. No significant differences were observed between uninfected conventional and uninfected SPF pigs.     

Trichinella spiralis: the influence of short chain fatty acids on the proliferation of lymphocytes, the goblet cell count and apoptosis in the mouse intestine

This study was carried out to determine the influence of short chain fatty acids (SCFA) on spleen and mesenteric lymph node lymphocyte proliferation, goblet cells and apoptosis in the mouse small intestine during invasion by Trichinella spiralis. BALB/c mice were infected with 250 larvae of T. spiralis. An SCFA water solution containing acetic, propionic and butyric acids (30:15:20 mM) was administered orally starting 5 days before infection and ending 20 days post infection (dpi). Fragments of the jejunum were collected by dissection 7 and 10 dpi, and were examined for apoptotic cells in the lamina propria of the intestinal mucosa, and for goblet cells. The proliferation index of the cultured spleen and mesenteric lymph node lymphocytes with MTT test was also determined. The orally administered SCFA solution decreased the proliferation of mesenteric lymph node lymphocytes in the mice infected with T. spiralis at both examination times, but did not influence the proliferative activity of the spleen cells. Seven dpi, both in the spleen and mesenteric lymph nodes, the highest proliferation index of concanavalin A (Con A)-stimulated lymphocytes was found in the group of uninfected animals receiving SCFA animals. This tendency could still be seen 10 dpi in the mesenteric lymph nodes but not in the spleen, where the proliferation index in this group had significantly decreased. In vitro studies revealed, that butyric and propionic acids added to the cell cultures suppressed the proliferation of Con A-stimulated mesenteric lymph nodes and spleen lymphocytes taken from uninfected and T. spiralis-infected mice. Acetic acid stimulated proliferation of splenocytes taken from uninfected mice but did not affect lymphocyte proliferation in mesenteric lymph nodes from uninfected or infected mice. Orally administered SCFA increased the number of goblet cells found in the epithelium of the jejunum 7 dpi, but this number had decreased 10 dpi. The number of apoptotic cells in the lamina propria of the intestinal mucosa of animals infected with the T. spiralis and receiving SCFA was also lower, particularly 10 dpi. The above results show that SCFA can participate in the immune response during the course of trichinellosis in mice.     

Methods to produce and safely work with large numbers of Toxoplasma gondii oocysts and bradyzoite cysts

Two major obstacles to conducting studies with Toxoplasma gondii oocysts are the difficulty in reliably producing large numbers of this life stage and safety concerns because the oocyst is the most environmentally resistant stage of this zoonotic organism. Oocyst production requires oral infection of the definitive feline host with adequate numbers of T. gondii organisms to obtain unsporulated oocysts that are shed in the feces for 3-10 days after infection. Since the most successful and common mode of experimental infection of kittens with T. gondii is by ingestion of bradyzoite tissue cysts, the first step in successful oocyst production is to ensure a high bradyzoite tissue cyst burden in the brains of mice that can be used for the oral inoculum. We compared two methods for producing bradyzoite brain cysts in mice, by infecting them either orally or subcutaneously with oocysts. In both cases, oocysts derived from a low passage T. gondii Type II strain (M4) were used to infect eight-ten week-old Swiss Webster mice. First the number of bradyzoite cysts that were purified from infected mouse brains was compared. Then to evaluate the effect of the route of oocyst inoculation on tissue cyst distribution in mice, a second group of mice was infected with oocysts by one of each route and tissues were examined by histology. In separate experiments, brains from infected mice were used to infect kittens for oocyst production. Greater than 1.3 billion oocysts were isolated from the feces of two infected kittens in the first production and greater than 1.8 billion oocysts from three kittens in the second production. Our results demonstrate that oral delivery of oocysts to mice results in both higher cyst loads in the brain and greater cyst burdens in other tissues examined as compared to those of mice that received the same number of oocysts subcutaneously. The ultimate goal in producing large numbers of oocysts in kittens is to generate adequate amounts of starting material for oocyst studies. Given the potential risks of working with live oocysts in the laboratory, we also tested a method of oocyst inactivation by freeze-thaw treatment. This procedure proved to completely inactivate oocysts without evidence of significant alteration of the oocyst molecular integrity.     

Therapeutic potential of the methanolic extract of Lepidium sativum seeds on mice infected with Trypanosoma evansi

The present study aimed to investigate the therapeutic potential of the methanolic extract of Lepidium sativum seeds in mice experimentally infected with Trypanosoma evansi. A total of thirty-two male Swiss albino mice were randomly divided into four groups: the first group was the normal control, while the second, third and fourth groups were infected intraperitoneally with 1 × 10⁴ trypanosomes. The third and fourth groups were treated with 100 μl of Lepidium sativum seed extract (LSSE) at a dose of 200 mg/kg body weight intraperitoneally (infected + LSSEI) and orally (infected + LSSEO) respectively, once a day, for a period of four days.Parasitaemia was found to be significantly raised in the untreated infected group, reaching 2 × 10⁷ at day 4 post-infection, but was significantly reduced by 65.5% and 88% in the mice treated orally and intraperitoneally with LSSE, respectively. The erythrocyte count, HCT, haemoglobin content, leucocyte count and the percentage of lymphocytes was significantly reduced in the untreated infected group, while the treatment with LSSE returned these parameters to their pre-infection values. In addition, our study proved that LSSE provided protection against liver tissue damage and decreased the levels of aspartate aminotransferase (AST) and alanine aminotransferase (ALT). The present study also established that intraperitoneal injection of LSSE is more effective than oral administration in the treatment of trypanosome infection in mice. In conclusion, the infection caused haematological, biochemical and histological changes that were ameliorated following treatment with LSSE.     

IL-22 Mediates Goblet Cell Hyperplasia and Worm Expulsion in Intestinal Helminth Infection

Type 2 immune responses are essential in protection against intestinal helminth infections. In this study we show that IL-22, a cytokine important in defence against bacterial infections in the intestinal tract, is also a critical mediator of anti-helminth immunity. After infection with Nippostrongylus brasiliensis, a rodent hookworm, IL-22-deficient mice showed impaired worm expulsion despite normal levels of type 2 cytokine production. The impaired worm expulsion correlated with reduced goblet cell hyperplasia and reduced expression of goblet cell markers. We further confirmed our findings in a second nematode model, the murine whipworm Trichuris muris. T.muris infected IL-22-deficient mice had a similar phenotype to that seen in N.brasiliensis infection, with impaired worm expulsion and reduced goblet cell hyperplasia. Ex vivo and in vitro analysis demonstrated that IL-22 is able to directly induce the expression of several goblet cell markers, including mucins. Taken together, our findings reveal that IL-22 plays an important role in goblet cell activation, and thus, a key role in anti-helminth immunity.     

Highly Active AntiRetroviral Therapy and cryptosporidiosis

In HIV infected persons, Cryptosporidium parvum causes chronic diarrhoea, which can be life-threatening in persons with AIDS and with a low CD4+ T cell count. However, a specific and effective therapy for this opportunistic infection does not yet exist. Since the use of a combination therapy with a highly active antiretroviral therapy (HAART), the prevalence of C. parvum infection in persons with AIDS has been strongly reduced. This favorable outcome was usually attributed to the recovery of the host immunity, however improvements from this opportunistic infection have been demonstrated even in the absence of immunological recovery. The aim of the present study was to determine whether HIV protease inhibitors (PIs) exert an anti-C. parvum activity. We selected the indinavir (an aspartyl protease inhibitor included in HAART) for our experiments, since a resolution of cryptosporidial enteritis in a person with AIDS after treatment with this drug has been reported. Human ileocecal adenocarcinoma tumor cells (HCT-8) were used as in vitro model. To determine whether or not indinavir had an effect on the parasite attachment to, or invasion of the HCT-8 cells, indinavir was added to the cultures at the same time as the infective dose (3 oocysts/cell) at one of the following concentrations: 0.1, 0.5, 5, 10, 20, and 50 microM (maximum DMSO content 0.5% vol/vol). To determine whether or not indinavir had an effect on established C. parvum infection, HCT-8 cells were infected with excysted oocysts at a ratio of 3 oocysts/cell at day 0, and then indinavir at a concentration of 50 microM was added to the cultures every 24 h for 4 days. The infection level was evaluated at 2, 3, 4 and 5 days p.i. using a flowcytometric assay. Three-day-old Balb/c mice were used as animal model, animals were infected per os with 50 microl of PBS containing 10(5) oocysts. The infected mice were divided into two groups (Group A and Group B), both of which received per os indinavir diluted in PBS with 0.1% DMSO at a concentration of 10 microM (24 mg/kg). For Group A, which consisted of 15 mice (3 litters), indinavir was administered at the same time that experimental infection was performed and then every day until the mice were sacrificed (i.e., 5 days p.i.), to determine the effect of indinavir on the attachment/invasion of the enterocytes. For Group B, which also consisted of 15 mice (3 litters), indinavir was administered after the infection was established (i.e., 72 h p.i.) and every day until being sacrificed, to determine the effect of indinavir on established infection. The mice of Group B were sacrificed 7, 10, 11 and 13 days p.i., corresponding to 4, 7, 8, and 10 days of treatment with indinavir. In vitro, the treatment of the excystated oocysts with different concentrations of indinavir reduced the percentage of HCT-8 infected cells in a dose-dependent manner. For established infection, the treatment with 50 microM of indinavir decreased the percentage of infected cells in a time-dependent manner. Treatment for 48 h resulted in a 40.1% reduction in infected cells (from 90% to 53%). After 72 h of treatment, the percentage of infected cells did not substantially differ from that observed after 48 h. Treatment for 96 h resulted in a 57.8% reduction (from 90 to 38%). In vivo, mice treated with indinavir at the same time they were infected with the oocysts showed a 93% reduction in the number of oocysts present in the entire intestinal contents and a 91% reduction in the number of intracellular parasites in the ileum. For established infection, indinavir treatment reduced the number of oocysts in the entire intestinal content by about 50% and the number of intracellular parasites in the ileum by about 70%. These data demonstrate that PIs directly exert an inhibitory effect on C. parvum and the extent of this effect depended on the specific dose and the duration of treatment. Although there are no reports of aspartyl proteases in C. parvum, the inhibitory effect of PIs on C. parvum growth in vitro suggests that aspartyl proteases could have some important functions for this parasite. In fact, proteolytic activities have been demonstrated during peak periods of excystation in C. parvum oocysts and cysteine and serine protease classes have been functionally associated with this process. Moreover, we identified several different C. parvum sequences that showed homology with a protein family related to aspartyl proteases. In prospect, PIs could be valuable for the chemotherapy of cryptosporidiosis.     

B-1 cells upregulate CD8 T lymphocytes and increase proinflammatory cytokines serum levels in oral encephalitozoonosis

Microsporidia are intracellular pathogens that cause severe disease in immunocompromised humans and animals. We recently demonstrated that XID mice are more susceptible to Encephalitozoon cuniculi infection by intraperitoneal route, evidencing the role of B-1 cells in resistance against infection. The present study investigated the resistance and susceptibility against E. cuniculi oral infection, including the role of B-1 cells. BALB/c and BALB/c XID (B-1 cells deficient) mice were orally infected with E. cuniculi spores. No clinical symptoms were observed in infected animals; histopathology showed lymphoplasmocytic enteritis with degeneration of the apexes of the villi in all infected groups. Higher parasite burden was observed in infected BALB/c XID mice. In the spleen and peritoneum, all infected mice showed a decrease of lymphocytes, including CD8⁺ T cells, mostly in infected BALB/c XID mice. Adoptive transfer of B-1 cells (XID + B-1) was associated with a lower parasite burden. Pro-inflammatory cytokines (IFN-γ, TNF-α and IL-6) increased mostly in infected XID + B1 mice. Together, the present results showed that BALB/c XID mice infected by the oral route were more susceptible to encephalitozoonosis than BALB/c mice, demonstrating the B-1 cells importance in the control of the immune response against oral E. cuniculi infection.     

In vivo anticoccidial,antioxidant, and anti-inflammatory activities of avocado fruit,Persea americana (Lauraceae), against Eimeria papillata infection

Apicomplexan parasites, especially Eimeria sp., are the main intestinal murine pathogens, that lead to severe injuries to farm and domestic animals. Many anticoccidial drugs are available for coccidiosis, which, leads to the development of drug-resistant parasites. Recently, natural products are considered as an alternative agent to control coccidiosis. This study was designed to evaluate the anticoccidial activity of the Persea americana fruit extract (PAFE) in male C57BL/6 mice. A total of 35 male mice were divided into seven equal groups (1, 2, 3, 4, 5, 6, and 7). At day 0, all groups except the first group which served as uninfected-untreated control were infected orally with 1 × 10³ E. papillata sporulated oocysts. Group 2 served as uninfected-treated control. Group 3 was considered an infected-untreated group. After 60 min of infection, groups 4, 5, and 6 were treated with oral doses of PAFE aqueous methanolic extract (100, 300, and 500 mg/kg of body weight, respectively). Group 7 was treated with amprolium (a reference drug for coccidiosis). PAFE with 500 mg/kg, was the most effective dose, inducing a significant reduction in the output of oocysts in mice feces (by about 85.41%), accompanied by a significant decrease in the number of the developmental parasite stages and a significant elevation of the goblet cells in the jejunal tissues. Upon treatment, a significant change in the oxidative status due to E. papillata infection was observed, where the levels of glutathione (GSH) increased, while, levels of malondialdehyde (MDA) and nitric oxide (NO) were decreased. In addition, the infection significantly upregulated the inflammatory cytokines of interleukin-1β (IL-1β), tumor necrosis factor-alpha (TNF-α), and interferon-γ (IFN-γ). This increase in mRNA expression of IL-1β, TNF-α, and IFN-γ was about 8.3, 10.6, and 4.5-fold, respectively, which significantly downregulated upon treatment. Collectively, P. americana is a promising medicinal plant with anticoccidial, antioxidant, and anti-inflammatory activities and could be used for the treatment of coccidiosis.     

Mucosal Immune Responses of Mice Experimentally Infected with Pygidiopsis summa (Trematoda: Heterophyidae)

Mucosal immune responses against Pygidiopsis summa (Trematoda: Heterophyidae) infection were studied in ICR mice. Experimental groups consisted of group 1 (uninfected controls), group 2 (infection with 200 metacercariae), and group 3 (immunosuppression with Depo-Medrol and infection with 200 metacercariae). Worms were recovered in the small intestine at days 1, 3, 5, and 7 post-infection (PI). Intestinal intraepithelial lymphocytes (IEL), mast cells, and goblet cells were counted in intestinal tissue sections stained with Giemsa, astra-blue, and periodic acid-Schiff, respectively. Mucosal IgA levels were measured by ELISA. Expulsion of P. summa from the mouse intestine began to occur from days 3-5 PI which sustained until day 7 PI. The worm expulsion was positively correlated with proliferation of IEL, mast cells, goblet cells, and increase of IgA, although in the case of mast cells significant increase was seen only at day 7 PI. Immunosuppression suppressed all these immune effectors and inhibited worm reduction in the intestine until day 7 PI. The results suggested that various immune effectors which include IEL, goblet cells, mast cells, and IgA play roles in regulating the intestinal mucosal immunity of ICR mice against P. summa infection.     

Suppression of peripheral eosinophilia by the coccidium Eimeria nieschulzi (Apicomplexa: Eimeriidae) in experimentally infected rats

Four groups of 60 rats each were used to examine interspecific interactions between Eimeria nieschulzi and Nippostrongylus brasiliensis. Rats in group 1 served as uninoculated controls. Group 2 rats were each injected subcutaneously with 2.0 X 10(3) L3 larvae of N. brasiliensis. Group 3 rats were each inoculated per os with 2.5 X 10(5) sporulated oocysts of E. nieschulzi. Rats in group 4 were first infected with 2.0 X 10(3) larvae of N. brasiliensis and, at 8 days postinoculation, with 2.5 X 10(5) oocysts of E. nieschulzi. Ten animals from groups 1-3 were sacrificed at 4-day intervals postinoculation and group 4 rats were sacrificed at 4-day intervals beginning after the secondary infection. Blood smears were prepared from each animal to determine differential blood cell counts, bone marrow was examined at the times of peak infection for absolute and relative numbers of eosinophils, portions of the duodenum and jejunum were examined histologically for mast cells, and feces obtained from the cecum and large intestine were examined for ova/gram of feces. Results revealed that relative numbers of peripheral neutrophils and monocytes became elevated during the course of infection for all infected animals, and rats infected with the helminth only also had elevated eosinophil levels. However, rats infected singly with E. nieschulzi, or concurrently with the coccidium and helminth, had peripheral eosinophil levels that were not significantly different from controls.(ABSTRACT TRUNCATED AT 250 WORDS)     

Murine liver response to Allium sativum treatment during infection induced-trypanosomiasis

Hepatic injury induced by trypanosomiasis is one of the major health problems not only to human but also to wild and domestic animals. This study aimed to evaluate the hepatoprotective role of Allium sativum extract (ASE) against Trypanosoma evansi infection in mice. Animals were divided into 4 groups. Group I received only saline while group II received ASE (20 mg/Kg). Animals of group III and group IV were infected with T. evansi. The latter group was treated with ASE. The infrared spectroscopic analysis of A. sativum extract exhibited bands between 3700 cm⁻¹ and 599 cm⁻¹. On day 4 post T. evansi infection, ASE decreased the parasitemia by about 15 fold. Also, ASE regulated the number of erythrocytes and leucocytes and the hemoglobin content. In addition, the histopathological damage was reduced after treatment with ASE. Moreover, the oxidant and the antioxidant markers (glutathione, malondialdehyde and catalase) were regulated in the infected-treated animals. Collectively, the results proved the protective role of ASE against T. evansi infection in mice.     

Response to ivermectin treatment of parasitic stages of Haemonchus contortus resistant or susceptible to ivermectin.

Two groups of 33 helminth-naive lambs were infected with 5,000 L3 of an ivermectin-resistant or -susceptible strain of Haemonchus contortus (groups R and S). On days 6, 10, 16, and 21 postinfection, 5 animals from each group were chosen at random and orally treated with 0.2 mg/kg of ivermectin. On each occasion, 2 randomly selected lambs from each group were also killed to determine the number and stage of development of the worms present at the time of treatment. These necropsies revealed that by day 6 early and late fourth-stage larvae were present, whereas on day 10 the early fifth stage had been reached; by days 16 and 21 all worms had reached the adult stage. Necropsies on day 28 postinfection revealed that although animals treated at day 6 had 26.3% fewer worms than the controls, there was no significant difference (P greater than 0.05) between worm burdens from any of the animals infected with the R strain and treated at different times after infection when compared with the untreated controls. With ivermectin significant reductions were obtained in the worm burdens of the animals infected with the susceptible strain; these were reduced by 96% when treatment was given on day 6 against fourth-stage larvae and 98.9% when the drug was given on day 21 against adult stages. From these results it is clear that resistance to ivermectin in this strain of H. contortus is present as early as the fourth larval stage.     

Development of patent infection in immunosuppressed C57Bl/6 mice with a single Cryptosporidium meleagridis oocyst

The ability of Cryptosporidium meleagridis to produce patent infection was studied in adult C57BL/6 mice that were immunosuppressed with dexamethasone phosphate provided in the drinking water at a dosage of 16 microg/ml. Four days after the onset of immunosuppression, mice were orally challenged with 1, 3, 10, or 1,000 C. meleagridis TU1867 oocysts per mouse. The mice were monitored daily for 18 days postinoculation for oocyst shedding. Five of 10 mice given a single oocyst, 4 of 5 mice given 3 oocysts, and all 9 mice given either 10 or 1,000 oocysts became infected and began shedding oocysts 5-7 days after challenge and continued to shed oocysts until the end of the experiment on day 18 postchallenge. Approximately 10(7) oocysts per mouse per day were excreted, regardless of the challenge dose. Neither the noninfected, immunosuppressed nor the inoculated, nonimmunosuppressed control mice shed oocysts. The excreted oocysts were confirmed to be those of C. meleagridis by polymerase chain reaction-restriction fragment length polymorphism analysis. We show that C. meleagridis, originally classified as an avian pathogen but recently found in humans with cryptosporidiosis, can produce patent infection in mice infected with a single oocyst. Moreover, we demonstrate that the immunosuppressed C57BL/6 adult mouse is an ideal host for the propagation of clonal populations of C. meleagridis isolates for laboratory studies.     

Goblet Cell Derived RELM-β Recruits CD4+ T Cells during Infectious Colitis to Promote Protective Intestinal Epithelial Cell Proliferation

Enterohemorrhagic Escherichia coli and related food and waterborne pathogens pose significant threats to human health. These attaching/effacing microbes infect the apical surface of intestinal epithelial cells (IEC), causing severe diarrheal disease. Colonizing the intestinal luminal surface helps segregate these microbes from most host inflammatory responses. Based on studies using Citrobacter rodentium, a related mouse pathogen, we speculate that hosts rely on immune-mediated changes in IEC, including goblet cells to defend against these pathogens. These changes include a CD4⁺ T cell-dependent increase in IEC proliferation to replace infected IEC, as well as altered production of the goblet cell-derived mucin Muc2. Another goblet cell mediator, REsistin-Like Molecule (RELM)-β is strongly induced within goblet cells during C. rodentium infection, and was detected in the stool as well as serum. Despite its dramatic induction, RELM-β’s role in host defense is unclear. Thus, wildtype and RELM-β gene deficient mice (Retnlb ^-/-) were orally infected with C. rodentium. While their C. rodentium burdens were only modestly elevated, infected Retnlb ^-/- mice suffered increased mortality and mucosal ulceration due to deep pathogen penetration of colonic crypts. Immunostaining for Ki67 and BrDU revealed Retnlb ^-/- mice were significantly impaired in infection-induced IEC hyper-proliferation. Interestingly, exposure to RELM-β did not directly increase IEC proliferation, rather RELM-β acted as a CD4⁺ T cell chemoattractant. Correspondingly, Retnlb ^-/- mice showed impaired CD4⁺ T cell recruitment to their infected colons, along with reduced production of interleukin (IL)-22, a multifunctional cytokine that directly increased IEC proliferation. Enema delivery of RELM-β to Retnlb ^-/- mice restored CD4⁺ T cell recruitment, concurrently increasing IL-22 levels and IEC proliferation, while reducing mucosal pathology. These findings demonstrate that RELM-β and goblet cells play an unexpected, yet critical role in recruiting CD4⁺ T cells to the colon to protect against an enteric pathogen, in part via the induction of increased IEC proliferation.     

Effect of Eimeria falciformis infection on the development of toxoplasmosis in mice

White mice previously infected with 10(2), 10(3) or 10(4) Eimeria falciformis oocysts on days 0, 5, 10 or 30 were inoculated per os with 10(1), 10(2), 10(3) or 10(4) Toxoplasma oocysts. While the results obtained for mice with higher Toxoplasma inocula were consistent, animals with 10(1) and 10(2) oocysts previous inoculation with Eimeria showed important differences related with those infected only with Toxoplasma. For example, survival time was higher in animals infected with both parasites, especially if inoculated with Eimeria 30 days before Toxoplasma infection. Furthermore the number of T. gondii cysts found in the animals previously infected with Eimeria was lower compared with mice inoculated with Toxoplasma only. Body weight of mice infected with Toxoplasma previous infection with Eimeria was almost normal in relation to those infected only with Toxoplasma, indicating a probable pathological effect due to the parasite, more evident in "non immunized" mice.     

Villous atrophy and expulsion of intestinal Trichinella spiralis are mediated by T cells.

The development of villous atrophy and crypt hyperplasia in, and expulsion of nematodes from, the small intestine of the mouse during Trichinella infection is shown to be mediated by T cells. During Trichinella infection, worms initially localise in the anterior half of the small intestine. Their expulsion from here after 6–8 days follows the onset of villous atrophy and crypt hyperplasia in the jejunum and the normal jejunal morphology is restored after complete expulsion of worms from the small intestine at 12–15 days. In thymectomised mice, according to the extent of T-cell depletion, worm localisation is atypical, expulsion is either delayed or absent, and villous atrophy and crypt hyperplasia are either delayed and reduced or absent. The adoptive immunization of infected thymectomised mice with mesenteric lymph node cells (including primed T blasts) from infected donors completely restores the normal host response and enhances the onset of crypt hyperplasia. These findings are discussed in relation to T-cell traffic and delayed-type hypersensitivity in the gut.     

Increased endothelial cell-leukocyte interaction in murine schistosomiasis: possible priming of endothelial cells by the disease

Background and Aims

Schistosomiasis is an intravascular parasitic disease associated with inflammation. Endothelial cells control leukocyte transmigration and vascular permeability being modulated by pro-inflammatory mediators. Recent data have shown that endothelial cells primed in vivo in the course of a disease keep the information in culture. Herein, we evaluated the impact of schistosomiasis on endothelial cell-regulated events in vivo and in vitro.

Methodology and Principal Findings

The experimental groups consisted of Schistosoma mansoni-infected and age-matched control mice. In vivo infection caused a marked influx of leukocytes and an increased protein leakage in the peritoneal cavity, characterizing an inflamed vascular and cellular profile. In vitro leukocyte-mesenteric endothelial cell adhesion was higher in cultured cells from infected mice as compared to controls, either in the basal condition or after treatment with the pro-inflammatory cytokine tumor necrosis factor (TNF). Nitric oxide (NO) donation reduced leukocyte adhesion to endothelial cells from control and infected groups; however, in the later group the effect was more pronounced, probably due to a reduced NO production. Inhibition of control endothelial NO synthase (eNOS) increased leukocyte adhesion to a level similar to the one observed in the infected group. Besides, the adhesion of control leukocytes to endothelial cells from infected animals is similar to the result of infected animals, confirming that schistosomiasis alters endothelial cells function. Furthermore, NO production as well as the expression of eNOS were reduced in cultured endothelial cells from infected animals. On the other hand, the expression of its repressor protein, namely caveolin-1, was similar in both control and infected groups.

Conclusion/Significance

Schistosomiasis increases vascular permeability and endothelial cell-leukocyte interaction in vivo and in vitro. These effects are partially explained by a reduced eNOS expression. In addition, our data show that the disease primes endothelial cells in vivo, which keep the acquired phenotype in culture.     

Proinflammatory cytokines in antilipopolysaccharide immunity against Klebsiella infections

This study was undertaken in order to determine whether proinflammatory cytokines are involved in a previously described protection against Klebsiella infection mediated by antilipopolysaccharide antibodies. BALB/c mice were infected intraperitoneally with a lethal challenge of Klebsiella pneumoniae Caroli. One group of mice was protected with monoclonal antibodies against lipopolysaccharide prior to infection and the second was not. We determined the number of colony-forming units at different time points in the blood of infected animals and paralleled them with plasma levels of five proinflammatory cytokines measured by enzyme immunoassays. Our results show that the two groups of animals tested expressed different plasma concentrations for all cytokines. The greatest difference was detected 24 hours after infection, with a higher production in the unprotected group. We concluded that a reduced cytokine production is partially responsible for the survival of protected animals.     

Anti-coccidial and anti-apoptotic activities of palm pollen grains on Eimeria papillata-induced infection in mice

The present work aimed to study the effect of palm pollen extract (PPE) as an anticoccidial and anti-apoptotic modulator during the course of murine intestinal Eimeria papillata infection. The fact that PPE has an anticoccidial efficacy against intestinal E. papillata infection in mice has been clarified by the reduction of faecal output of oocysts on day five post infection from 49.5 × 10³ to 34 × 10³ oocyst/g. Moreover, the number of intracellular eimerian stages of zygots and developing oocysts decreased by about 89% and that of schizonts and gamonts to 42% and 72%, respectively. E. papillata infection also induced an increase in the number of apoptotic cells from 17.5 to 122.8 apoptotic nuclei/10 villous crypt units (VCU). In addition, it caused a state of systemic inflammatory response as revealed by an elevation in levels of the pro-inflammatory biomarkers, inducible nitric oxide synthase (iNOs) and tumor necrosis factor alpha (TNF-α) from 5.3 and 78.3 to 33 pmol ml^?1 and 96.3 pg ml^?1 in blood, respectively, with concurrent duplication in the total leucocytic number. Upon treatment of infected mice with the aqueous PPE, the activity of iNOs was reduced by 55% and the level of TNF-α was decreased by 30%. Moreover, the total leucocytic count was significantly reduced from 9.05 × 10³ to 7.8 × 10³ cells/mm³. Based on our results, PPE showed both anti-coccidial, anti-inflammatory and anti-apoptotic activities. So it can be used in developing new herbal medicine against animal coccidiosis and may be suitable agent for treating eimeriosis associated inflammatory response.