OBJECTIVETo observe Trichomonas vaginalis (T. vaginalis) adhering to and phagocytizing male genitourinary epithelial cells in order to study the pathogenetic mechanism of male trichomoniasis.

METHODSCultured T. vaginalis bodies were incubated with male genitourinary epithelial cells, and then the ultrastructure was observed with transmission electron microscopy.

RESULTST. vaginalis adhered to epithelial cells like amoeba, and formed pseudopodium or surface invagination surrounding or nibbling other parts of the epithelial cytoplasm.

CONCLUSIONST. vaginalis has the speciality of adhering to and phagocytizing to male genitourinary epithelial cells. Genitourinary epithelial cells may be injured directly by the phagocytosis of T. vaginalis. Attention has to be paid to the correlation.

Animals ; Bacterial Adhesion ; Epithelial Cells ; parasitology ; Genitalia, Male ; parasitology ; Humans ; Male ; Microscopy, Electron ; Trichomonas vaginalis ; ultrastructure

To determine alteration of immune responses during visceral larva migrans (VLM) caused by Toxascaris leonina at several time points, we experimentally infected mice with embryonated eggs of T. leonina and measured T-helper (Th) cell-related serial cytokine production after infection. At day 5 post infection (PI), most larvae were detected from the lungs, spleen, intestine, and muscle. Expression of thymic stromal lymphopoietin (TSLP) and CCL11 (eotaxin) showed a significant increase in most infected organs, except the intestine. However, expression of the CXCL1 (Gro-alpha) gene was most highly enhanced in the intestine at day 14 PI. Th1-related cytokine secretion of splenocytes showed increases at day 28 PI, and the level showed a decrease at day 42 PI. Th2-related cytokine secretion of splenocytes also showed an increase after infection; in particular, IL-5 level showed a significant increase at day 14 PI, and the level showed a decrease at day 28 PI. However, levels of Th17-related cytokines, IL-6 and IL-17A, showed gradual increases until day 42 PI. In conclusion, Th1, Th2, and Th17-related cytokine production might be important in immune responses against T. leonina VLM in experimental mice.
Animals ; Brain/parasitology ; Cytokines/*metabolism ; Female ; Gene Expression Regulation ; Heart/parasitology ; Interleukins/*metabolism ; Intestines/parasitology ; Larva Migrans, Visceral/*immunology/parasitology ; Liver/parasitology ; Lung/parasitology/pathology ; Mice ; Mice, Inbred C57BL ; Muscles/parasitology ; Spleen/parasitology ; Th1 Cells/immunology ; Th17 Cells/immunology ; Th2 Cells/immunology ; Toxascaris/*immunology

We trapped a rat (Rattus norvegicus) infected with Capillaria hepatica. At necropsy, grossly yellowish-white nodules (2-3 mm in diameter) were noted to be scattered on the liver's surface. Microscopically, granulomatous and fibrotic nodules that contained the eggs and/or adult worms of Capillaria hepatica were detected in the liver. Septal fibrosis was diffusely formed throughout the liver. There were a number of ED1-positive macrophages located in the sinusoids of the pseudolobules. On the double staining, myofibroblasts and mast cells were generally observed within the fibrous septa with the mast cells in close proximity to the myofibroblasts. We suggest that the interactions between macrophages, myofibroblasts and mast cells play a role in the septal fibrosis observed in rats infected by Capillaria hepatica.
Animals ; *Capillaria ; Enoplida Infections/immunology/parasitology/*veterinary ; Fibroblasts/immunology ; Liver/parasitology/pathology ; Macrophages/immunology ; Mast Cells/immunology ; Rats ; Rodent Diseases/*immunology/*parasitology/pathology

Eimeria tenella, an intracellular protozoan parasite infecting the epithelial cells of the ceca of chickens, causes severe diarrhea and bleeding that can lead its host to death. It is of interest that E. tenella first penetrate into the mucosal intraepithelial lymphocytes (IEL) before they parasitize crypt or villous epithelial cells. This in vitro study was undertaken to know whether the penetration of E. tenella into such a lymphoid cell is a beneficial step for the parasite survival and development. Three sequential experiments were performed. First, the in vitro established bovine kidney cell line, MDBK cells, were evaluated for use as host cells for E. tenella, through morphological observation. Second, the degree of parasite development and multiplication in MDBK cells was quantitatively assayed using radioisotope-labelled uracil (3H-uracil). Third, the E. tenella sporozoites viability was assayed after preincubation of them with chicken spleen cells. E. tenella oocysts obtained from the ceca of the infected chickens were used for the source of the sporozoites. Spleen cells (E) obtained from normal chickens (FP strain) were preincubated with the sporozoites (T) at the E:T ratio of 100:1, 50:1 or 25:1 for 4 or 12 hours, and then the mixture was inoculated into the MDBK cell monolayer. Morphologically the infected MDBK cells revealed active schizogonic cycle of E. tenella in 3-4 days, which was characterized by the appearance of trophozoites, and immature and mature schizonts containing merozoites. The 3H-uracil uptake by E. tenella increased gradually in the MDBK cells, which made a plateau after 48-60 hours, and decreased thereafter. The uptake amount of 3H-uracil depended not only upon the inoculum size of the sporozoites but also on the degree of time delay (preincubation; sporozoites only) from excystation to inoculation into MDBK cells. The 3H-uracil uptake became lower as the preincubation time was prolonged. In comparison, after preincubation of sporozoites with spleen cells for 4 or 12 hours, the 3H-uracil uptake was significantly increased compared with that of control group. From the results, it was inferred that, although the penetration of E. tenella sporozoites into the lymphoid cells such as IEL is not an essential step, it should be at least a beneficial one for the survival and development of sporozoites in the chicken intestine.
Cattle- ; Cell-Line ; Cells,-Cultured ; Chickens- ; English-Abstract ; *Eimeria-growth-and-development ; *Kidney-parasitology ; *Lymphocytes-parasitology ; *Spleen-cytology

Trichomonas vaginalis commonly causes vaginitis and perhaps cervicitis in women and urethritis in men and women. Macrophages are important immune cells in response to T. vaginalis infection. In this study, we investigated whether human macrophages could be involved in inflammation induced by T. vaginalis. Human monocyte-derived macrophages (HMDM) were co-cultured with T. vaginalis. Live, opsonized-live trichomonads, and T. vaginalis lysates increased proinflammatory cytokines, such as TNF-alpha, IL-1beta, and IL-6 by HMDM. The involvement of nuclear factor (NF)-kappaB signaling pathway in cytokine production induced by T. vaginalis was confirmed by phosphorylation and nuclear translocation of p65 NF-kappaB. In addition, stimulation with live T. vaginalis induced marked augmentation of nitric oxide (NO) production and expression of inducible NO synthase (iNOS) levels in HMDM. However, trichomonad-induced NF-kappaB activation and TNF-alpha production in macrophages were significantly inhibited by inhibition of iNOS levels with L-NMMA (NO synthase inhibitor). Moreover, pretreatment with NF-kappaB inhibitors (PDTC or Bay11-7082) caused human macrophages to produce less TNF-alpha. These results suggest that T. vaginalis stimulates human macrophages to produce proinflammatory cytokines, such as IL-1, IL-6, and TNF-alpha, and NO. In particular, we showed that T. vaginalis induced TNF-alpha production in macrophages through NO-dependent activation of NF-kappaB, which might be closely involved in inflammation caused by T. vaginalis.
Animals ; Cells, Cultured ; Cytokines/*immunology ; Humans ; Macrophages/*immunology/parasitology ; Nitric Oxide/*immunology ; Trichomonas Infections/*immunology/parasitology ; Trichomonas vaginalis/*immunology

Trichomonas vaginalis commonly causes vaginitis and perhaps cervicitis in women and urethritis in men and women. Macrophages are important immune cells in response to T. vaginalis infection. In this study, we investigated whether human macrophages could be involved in inflammation induced by T. vaginalis. Human monocyte-derived macrophages (HMDM) were co-cultured with T. vaginalis. Live, opsonized-live trichomonads, and T. vaginalis lysates increased proinflammatory cytokines, such as TNF-alpha, IL-1beta, and IL-6 by HMDM. The involvement of nuclear factor (NF)-kappaB signaling pathway in cytokine production induced by T. vaginalis was confirmed by phosphorylation and nuclear translocation of p65 NF-kappaB. In addition, stimulation with live T. vaginalis induced marked augmentation of nitric oxide (NO) production and expression of inducible NO synthase (iNOS) levels in HMDM. However, trichomonad-induced NF-kappaB activation and TNF-alpha production in macrophages were significantly inhibited by inhibition of iNOS levels with L-NMMA (NO synthase inhibitor). Moreover, pretreatment with NF-kappaB inhibitors (PDTC or Bay11-7082) caused human macrophages to produce less TNF-alpha. These results suggest that T. vaginalis stimulates human macrophages to produce proinflammatory cytokines, such as IL-1, IL-6, and TNF-alpha, and NO. In particular, we showed that T. vaginalis induced TNF-alpha production in macrophages through NO-dependent activation of NF-kappaB, which might be closely involved in inflammation caused by T. vaginalis.
Animals ; Cells, Cultured ; Cytokines/*immunology ; Humans ; Macrophages/*immunology/parasitology ; Nitric Oxide/*immunology ; Trichomonas Infections/*immunology/parasitology ; Trichomonas vaginalis/*immunology

The pathogenesis and pathophysiology of Acanthamoeba infections remain incompletely understood. Phos-pholipases are known to cleave phospholipids, suggesting their possible involvement in the host cell plasma membrane disruption leading to host cell penetration and lysis. The aims of the present study were to determine phospholipase activities in Acanthamoeba and to determine their roles in the pathogenesis of Acanthamoeba. Using an encephalitis isolate (T1 genotype), a keratitis isolate (T4 genotype), and an environmental isolate (T7 genotype), we demonstrated that Acanthamoeba exhibited phospholipase A2 (PLA2) and phospholipase D (PLD) activities in a spectrophotometry-based assay. Interestingly, the encephalitis isolates of Acanthamoeba exhibited higher phospholipase activities as compared with the keratitis isolates, but the environmental isolates exhibited the highest phospholipase activities. Moreover, Acanthamoeba isolates exhibited higher PLD activities compared with the PLA2. Acanthamoeba exhibited optimal phospholipase activities at 37degrees C and at neutral pH indicating their physiological relevance. The functional role of phospholipases was determined by in vitro assays using human brain microvascular endothelial cells (HBMEC), which constitute the blood-brain barrier. We observed that a PLD-specific inhibitor, i.e., compound 48/80, partially inhibited Acanthamoeba encephalitis isolate cytotoxicity of the host cells, while PLA2-specific inhibitor, i.e., cytidine 5'-diphosphocholine, had no effect on parasite-mediated HBMEC cytotoxicity. Overall, the T7 exhibited higher phospholipase activities as compared to the T4. In contract, the T7 exhibited minimal binding to, or cytotoxicity of, HBMEC.
Acanthamoeba/*enzymology/genetics/*isolation & purification/physiology ; Cell Adhesion ; Cells, Cultured ; Endothelial Cells/parasitology ; Humans ; Keratitis/*parasitology ; Phospholipase D/genetics/*metabolism ; Phospholipases A2/genetics/*metabolism ; Protozoan Proteins/genetics/*metabolism ; Soil/*parasitology

To study the basic pathological changes of small intestine in metagonimiasis, light- and electron microscopic studies were made, using a total of 21 cats which were experimentally infected with metacercariae of Metagonimus yokogawai. The metacercariae were obtained from naturally infected sweetfish (Plecoglossus altivelis) by digestion technique. The cats were divided in control, light-infection(10,000 metacercariae infected) and heavy-infection(50,000 metacercariae infected) groups. Cats were killed at the 5th, 10th, 15th day, and 4th, 8th and 10th week after the infection. And the small intestine was prepared for the study. Pathological studies comprised gross examination, worm distribution pattern, light microscopic examination and both transmission and scanning electron microscopic examinations. The results obtained were summarized as follows. Gross morphologic changes were the most marked during the first 2 weeks after infection. The gross abnormalities were severer in the heavily infected animals. The changes were dryness and listlessness of serosal surface due to dehydration, mushy and/or watery intestinal content, effacement of transverse nodes and enlargement of mesenteric lymph folds and Peyer's patches. After 4 weeks of infection, these changes became less marked showing a tendency to return to normal. The sectioned flukes were distributed from duodenum to proximal ileum. However, individual variation was marked in distribution. In the heavy-infection group, the locality of parasitism tended to extend more distally. The locality of M. yokogawai in the intervillous space was mostly in the lower-most portion of intervillous space, where they compressed and eroded epithelial cells probably due to mechanical damage to the structure. Very rarely the worms were found in lumen of Lierberkuehn's crypt, and reaching, in two occasions, into proprial lymphoid tissue. Light-microscopically the lesion was restricted in mucosa: Early mucosal changes were shortening, blunting, fusion, and thickening of the villi, crypt hypertrophy with consequent decrease of villus/crypt ratio, as well as stromal changes of edema, capilliary ectasia and marked inflammatory cell infiltration of lymphocytes and plasma cells. Goblet cells were markedly reduced in number as with depletion of its cytoplasmic content. In the later stages of infection, mucosa restored its normal configuration in spite of persistent parasitism of the worms. At the infection stage of 5-15 days, there was significant shortening of the microvillous height with varible destruction of glycocalyx in electron microscopic examination. With lapse of infection time, microvilli became to restore the normal pattern. With these morphological changes, it appears that diarrhea in experimental metagonimiasis would be related to the decrease of absorptive surface of the small intestine particularly in the early phase of infection. The significant changes seen in villi and microvilli might be due to massive intrusion or invasion of Metagonimus worms into the crypts, causing direct mechanical and possible host-immune response to the small bowel mucosa.
parasitology-helminth-trematoda ; metagonimiasis ; Metagonimus yokogawai ; pathology ; cat-intestine ; edema ; lymphocytes ; plasma cells ; goblet cell

In vitro culture of Toxoplasma gondii in HL-60 cells cnd cell-mediated immunity against Toxoplasma in dimethylsulfoxide(DMSO)-induced HL-60 cells, i.e., differentiation into granulocytes, were pursued. HL-60 cells were treated with various concentrations of DMSO, and 1.3%(v/v) for 3 day incubation was chosen as the optimal condition for differentiation into granulocytes. The degree of differentiation was assayed in physiological and functional aspects in addition to morphological point. When treated with 1.3% DMSO for 3 days, HL-60 cells did not synthesize DNA materials beyond background level, and showed active chemotactic response to chemotactic peptide, formyl-methionyl-leucyl-phenylalanine(FMLP). Morphologically promyelocytes of high nuclear/cytoplasmic(N/C) ratio changed to granulocytes of relatively low N/C ratio. The relationships between HL-60 cells or DMSO-induced HL-60 cells and Toxoplasma were examined after stain with Giemsa and fluorescent dye (acridine orange). HS-60 cells did not show any sign of toxoplasmacidal activity but showed intracellular proliferation of Toxoplasma to form rosette for 72 hr co-culture. In contrast, DMSO-induced HL-60 cells phagocytosed Toxoplasma within 1 hr, and performed a process of intracellular digestion of Toxoplasma thereafter. With the above results, it is suggested that phagosome-lysosome fusion is one of the critical events for the parasitism by Toxoplasma or for susceptibility of host cells. The in vitro culture system of this study has offered a defined condition to study the protozoan parasite-host cell interactions.
parasitology-protozoa ; Toxoplasma gondii ; HL-60 cells ; dimethylsulfoxide ; in vitro culture ; dimethylsulfoxide

OBJECTIVETo investigate the role of excretory/secretory antigens from Clonorchis sinensis (CsESAs) in hepatic fibrosis induced by C. sinensis infection in rats and explore the possible mechanism.

METHODSCsESAs was collected from adult C. sinensis cultured in sterile condition for 12 h and injected intraperitoneally in Wistar rats. Masson staining was used to observe the changes in the hepatic collagen fiber after the injection. HE staining and immunofluorescence staining were performed to detect the expression of alpha-smooth muscle actin (alpha-SMA) to examine the proliferation and the activity of hepatic stellate cells. The specific antibody titer of CsESAs was determined using enzyme-linked immunosorbent assay to investigate the role of the antigen-antibody complex in the development of hepatic fibrosis.

RESULTSAfter intraperitoneal injection of CsESAs, obvious hepatic fibrosis and hepatic stellate cell proliferation and activation were observed in the rat livers. The severity of the hepatic fibrosis was associated with the dose of CsESAs injected, whereas the titer of the specific antibody against CsESAs showed no direct relation to the hepatic fibrosis.

CONCLUSIONIntraperitoneal injection of CsESAs can cause hepatic stellate cell activation and hepatic fibrosis in rats, but the antigen-antibody complex does not seem to play the key role in the activation of the hepatic stellate cells.

Actins ; metabolism ; Animals ; Antigens, Helminth ; immunology ; Clonorchiasis ; parasitology ; Clonorchis sinensis ; immunology ; pathogenicity ; Hepatic Stellate Cells ; pathology ; Liver Cirrhosis ; immunology ; parasitology ; Male ; Rats ; Rats, Wistar