Therapeutic Peptide RF16 Derived from CXCL8 Inhibits MDA-MB-231 Cell Invasion and Metastasis.

Interleukin (IL)-8 plays a vital role in regulating inflammation and breast cancer formation by activating CXCR1/2. We previously designed an antagonist peptide, (RF16), to inhibits the activation of downstream signaling pathways by competing with IL-8 in binding to CXCR1/2, thereby inhibiting IL-8-induced chemoattractant monocyte binding. To evaluate the effect of the RF16 peptide on breast cancer progression, triple-negative MDA-MB-231 and ER-positive MCF-7 breast cancer cells were used to investigate whether RF16 can inhibit the IL-8-induced breast cancer metastasis. Using growth, proliferation, and invasiveness assays, the results revealed that RF16 reduced cell proliferation, migration, and invasiveness in MDA-MB-231 cells. The RF16 peptide also regulated the protein and mRNA expressions of epithelial-mesenchymal transition (EMT) markers in IL-8-stimulated MDA-MB-231 cells. It also inhibited downstream IL-8 signaling and the IL-8-induced inflammatory response via the mitogen-activated protein kinase (MAPK) and Phosphoinositide 3-kinase (PI3K) pathways. In the xenograft tumor mouse model, RF16 synergistically reinforces the antitumor efficacy of docetaxel by improving mouse survival and retarding tumor growth. Our results indicate that RF16 significantly inhibited IL-8-stimulated cell growth, migration, and invasion in MDA-MB-231 breast cancer cells by blocking the activation of p38 and AKT cascades. It indicated that the RF16 peptide may serve as a new supplementary drug for breast cancer.

Use of wogonin as a cooperative drug with praziquantel to better combat schistosomiasis.

BACKGROUND: Schistosomiasis is one of the most devastating tropical diseases in the world. Currently, praziquantel (PZQ) represents the best pharmacological option for the treatment of schistosomiasis as it effectively kills the worm. However, the inability to reverse established liver damages often makes treatment futile. In the current study, we investigate whether combining the use of wogonin, a compound that was found to be liver-protective, with PZQ can attribute to the greatest beneficial effect in Schistosoma mansoni-infected mice. METHODS: To determine the protective effect of PZQ-wogonin treatment on S. manosni-infected mice, histopathological analysis was done to evaluate the granuloma size and fibrotic areas in the liver. Western blotting was performed to analyze several injuries-related markers including fibrotic markers, inflammasomes, and apoptotic markers. Scanning electron microscopy was done to evaluate the effect of wogonin on the worms, and the worm and egg burden was calculated. RESULTS: Our results showed that PZQ-wogonin treatment significantly improved liver histopathology of S. mansoni-infected mice. Further analysis showed that PZQ-wogonin combinations are more effective in reducing fibrosis, inflammation, and apoptosis in the liver than that of individual drug use. Furthermore, our results revealed that wogonin is anthelmintic; and it works better with PZQ in reducing hepatic egg burden, further lessen the disease progression. CONCLUSION: In general, this combinatorial strategy may represent a new and effective approach to schistosomiasis treatment.

A Multitarget Therapeutic Peptide Derived From Cytokine Receptors Based on in Silico Analysis Alleviates Cytokine-Stimulated Inflammation.

Septicemia is a severe inflammatory response caused by the invasion of foreign pathogens. Severe sepsis-induced shock and multiple organ failure are the two main causes of patient death. The overexpression of many proinflammatory cytokines, such as TNF-α, IL-1ß, and IL-6, is closely related to severe sepsis. Although the treatment of sepsis has been subject to many major breakthroughs of late, the treatment of patients with septic shock is still accompanied by a high mortality rate. In our previous research, we used computer simulations to design the multifunctional peptide KCF18 that can bind to TNF-α, IL-1ß, and IL-6 based on the binding regions of receptors and proinflammatory cytokines. In this study, proinflammatory cytokines were used to stimulate human monocytes to trigger an inflammatory response, and the anti-inflammatory ability of the multifunctional KCF18 peptide was further investigated. Cell experiments demonstrated that KCF18 significantly reduced the binding of proinflammatory cytokines to their cognate receptors and inhibited the mRNA and protein expressions of TNF-α, IL-1ß, and IL-6. It could also reduce the expression of reactive oxygen species induced by cytokines in human monocytes. KCF18 could effectively decrease the p65 nucleus translocation induced by cytokines, and a mice endotoxemia experiment demonstrated that KCF18 could reduce the expression of IL-6 and the increase of white blood cells in the blood stimulated by lipopolysaccharides. According to our study of tissue sections, KCF18 alleviated liver inflammation. By reducing the release of cytokines in plasma and directly affecting vascular cells, KCF18 is believed to significantly reduce the risk of vascular inflammation.

Resolution of systemic complications in Schistosoma mansoni-infected mice by concomitant treatment with praziquantel and Schisandrin B.

Schistosomiasis is a tropical parasitic disease, in which the major clinical manifestation includes hepatosplenomegaly, portal hypertension, and organs fibrosis. Clinically, treatment of schistosomiasis involves the use of praziquantel (PZQ) and supportive care, which does not improve the patient's outcome as liver injuries persist. Here we show the beneficial effects of using PZQ in combination with Schisandrin B (Sch B). Concomitant treatment with PZQ and Sch B resulted in a significant improvement of hepatosplenomegaly and fibrosis, compared with single-agent treatment. We also demonstrated that PZQ-Sch B treatment ameliorates injuries in the lungs and intestine better than the sole use of PZQ or Sch B. In addition, PZQ-Sch B treatment improves the survival of S. mansoni-infected mice, and the treatment combination yields better therapeutic outcomes, as indicated by a partial improvement in neurological function. These results were accompanied by a reduction in neurological injuries. Collectively, we suggest that PZQ-Sch B concomitant therapy may be useful to alleviate schistosomiasis-associated liver injuries and prevent systemic complications.

Switched phenotypes of macrophages during the different stages of Schistosoma japonicum infection influenced the subsequent trends of immune responses.

BACKGROUND: Macrophages play crucial roles in immune responses during the course of schistosomal infections. METHODS: We currently investigated influence of immunocompetent changes in macrophages via microarray-based analysis, mRNA expression analysis, detection of serum cytokines, and subsequent evaluation of the immune phenotypes following the differentiation of infection-induced lymphocytes in a unique T1/T2 double-transgenic mouse model. RESULTS: The gradual upregulation of genes encoding YM1, YM2, and interleukin (IL)-4/IL-13 receptors in infected mice indicated the role of type 2 alternatively activated macrophages (M2, AAMφs) in immune responses after Schistosoma japonicum egg production. FACS analysis showed that surface markers MHC class II (IA/IE) and CD8α+ of the macrophages also exhibited a dramatic change at the various time points before and after egg-production. The transgenic mouse experiments further demonstrated that the shifting of macrophage phenotypes influenced the percentage of helper T (Th)-2 cells, which was observed to be higher than that of Th1 cells, which increased only at 3 and 5 weeks post-infection. The differentiation of effector B cells showed a similar but more significant trend toward type-2 immunity. CONCLUSION: These results suggest that the infection of mice with S. japonicum resulted in a final Th2- and Be2-skewed immune response. This may be due to phenotypic changes in the macrophages. The influence of alternatively activated macrophages was also activated by S. japonicum egg production. This study elucidated the existence of variations in immune mechanisms at the schistosome infection stages.

Antifibrotic and anthelminthic effect of casticin on Schistosoma mansoni-infected BALB/c mice.

BACKGROUND/PURPOSE: Schistosomiasis is an important tropical disease caused by Schistosoma. Although the pathogenesis of liver fibrosis has been intensively studied, the choice of effective treatment is still inadequate. In this study, we aimed to investigate the potential of using Casticin to treat Schistosoma mansoni-induced liver fibrosis. METHODS: BALB/c mice were divided into three groups - control, infection, and treatment group. The infection and treatment group were percutaneously infected with 100-120 cercariae. Mice from the treatment group were treated with 20 mg/kg/day Casticin for 14 consecutive days to investigate the potential protective effects of Casticin. Mice were sacrificed and were used for histological, RNA, protein, and parasite burden analysis. RESULTS: Our results showed that hepatic fibrosis was significantly attenuated, as indicated by histology and reduction of fibrotic markers such as collagen AI, transforming growth factor ß (TGF-ß), and α-smooth muscle actin (α-SMA). Furthermore, Casticin treatment significantly reduced worm burden. Anthelmintic effect of Casticin was also observed by scanning electron microscopy. CONCLUSION: Collectively, our study suggested that Casticin may be a beneficial candidate in treating S. mansoni infection.

Heat-killed Propionibacterium acnes augment the protective effect of 28-kDa glutathione S-transferases antigen against Schistosoma mansoni infection.

Sm28GST is one of the candidate antigens for Schistosoma mansoni vaccine. Already Sm28GST vaccine formulations have shown to be protective against S. mansoni infection. Currently, efforts have been put into finding an adjuvant to enhance the immunity induced by Sm28GST. In the present work, we investigated whether heat-killed Propionibacterium acnes can be served as a potential adjuvant for recombinant Sm28GST (rSm28GST) antigen. As the results showed, P. acnes successfully modulated the Th1 humoral immune response induced by rSm28GST. Stronger Th1 cytokines responses were also observed in mice immunized with P. acnes-adjuvanted rSm28GST. Immunization of mice with P. acnes-adjuvanted rSm28GST was able to reduce worm burden and hepatic egg burden by 54.20 and 73.61%. Reduced granuloma size and count, as well as improved liver histology, were seen in P. acnes-adjuvanted rSm28GST immunized mice. These data suggest that P. acnes may evoke a stronger rSm28GST-induced immune response, higher resistance to S. mansoni infection, and more profound protection against S. mansoni-induced liver damages.

Ameliorative effects of Schisandrin B on Schistosoma mansoni-induced hepatic fibrosis in vivo.

Schistosomiasis is second only to malaria as the most devastating parasitic disease in the world. It is caused by the helminths Schistosoma mansoni (S. mansoni), S. haematobium, or S. japonicum. Typically, patients with schistosomiasis suffer from symptoms of liver fibrosis and hepatosplenomegaly. Currently, patients were treated with praziquantel. Although praziquantel effectively kills the worm, it cannot prevent re-infection or resolve liver fibrosis. Also, current treatment options are not ample to completely cure liver fibrosis and splenic damages. Moreover, resistance of praziquantel has been reported in vivo and in vitro studies. Therefore, finding new effective treatment agents is urgently needed. Schisandrin B (Sch B) of Schisandra chinensis has been shown to protect against different liver injuries including fatty liver disease, hepatotoxicity, fibrosis, and hepatoma. We herein investigate the potential of using Sch B to treat S. mansoni-induced liver fibrosis. Results from the present study demonstrate that Sch B is beneficial in treating S. mansoni-induced liver fibrosis and splenic damages, through inhibition of inflammasome activation and apoptosis; and aside from that regulates host immune responses. Besides, Sch B treatment damages male adult worm in the mice, consequently helps to reduce egg production and lessen the parasite burden.

Detection and genotyping of Giardia duodenalis from cattle and pigs in Hualien country, Eastern Taiwan.

BACKGROUND: Giardia duodenalis is a zoonotic protozoan parasite causing diarrhea through waterborne or fecal-oral infection. The cysts can live in the drinking water and cause pandemic diseases. In Taiwan, very little information is available regarding the epidemiology of G. duodenalis in domestic animals. METHODS: Fecal samples were collected from cattle (n = 156) and pigs (n = 141) in Hualien country, eastern Taiwan. Detection and genotyping were done by microscopy examination of fecal samples and amplification of the ß-giardin gene using nested PCR. RESULTS: The prevalence of G. duodenalis infection was 19.87% for cattle (31/156) and 4.26% for pigs (6/141). Using nested PCR, 30 infected samples found in cattle belonged to Assemblage E, and one sample belonged to Assemblage D. For pigs, four samples belonged to Assemblage E, one belonged to Assemblage D, and another one belonged to Assemblage A. In addition, these results showed that G. duodenalis Assemblage A was detected in pigs and may cause zoonotic transmission. CONCLUSION: This is the first epidemiological investigation of G. duodenalis infection in animals in Hualien, Taiwan. These results could provide epidemiological information for disease control and public health protection.

Mitochondrial dynamics in Angiostrongylus cantonensis-infected mouse brain.

Angiostrongylus cantonensis is one of the most widespread parasites causing central nervous system (CNS) diseases in mammals. Since the mitochondrion is an essential cell organelle responsible for both physiological and pathological processes, its dysfunction might lead to inflammation and multiple disorders. In this study we aimed to investigate the changes in mitochondrial dynamics that occur in the mouse brain upon infection with A. cantonensis, using molecular biology techniques such as polymerase chain reaction (PCR), western blot analysis, transmission electron microscopy (TEM), and different staining methods. Here, we show that mouse brain infected with A. cantonensis exhibits altered mitochondrial dynamics, including fission, fusion, and biogenesis. Additionally, we demonstrate that caspases and B-cell lymphoma 2 (BCL-2) were significantly upregulated in A. cantonensis-infected brain. These results are indicative of the occurrence of apoptosis during A. cantonensis infection, which was further confirmed by terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) staining. These findings suggest the change in mitochondrial dynamics in A. cantonensis-infected brain, providing another point of view on the pathogenesis of meningoencephalitis caused by A. cantonensis infection.

Angiostrongylus cantonensis activates inflammasomes in meningoencephalitic BALB/c mice.

Angiostrongylus cantonensis is a metastrongyloid nematode that causes eosinophilic meningoencephalitis in humans. A high infestation of A. cantonensis can cause permanent brain damage or even death. The inflammasome is an oligomeric molecular platform that can detect microbial pathogens and activate inflammatory cytokines. The recognition of larval surface antigens by pattern recognition receptors (PRRs) can cause oligomerization of the NOD-like receptor (NLR) or absent in melanoma 2 (AIM2) with the adaptor apoptosis-associated speck-like protein containing a caspase recruitment domain (ASC) to form a caspase-1-activating scaffold. Activated caspase-1 converts pro-inflammatory cytokines into their mature, active forms. Helminths infection has been shown to activate NACHT, LRR, and PYD domains-containing protein 3 (NLRP3) inflammasomes. In this study, we aimed to investigate the mechanism of inflammasome activation upon A. cantonensis infection in a mouse model. This study provides evidence that A. cantonensis infection can activate NLRP1B and NLRC4 inflammasomes and promote pyroptosis to cause meningoencephalitis.

Immunopathological effects of Agaricus blazei Murill polysaccharides against Schistosoma mansoni infection by Th1 and NK1 cells differentiation.

In this study, we examined the ability of A. blazei Murill polysaccharides (AB-PS) to activate the immune system in vivo and the protective activity exhibited against parasitic S. mansoni in the murine model. AB-PS treatment significantly reduced the worm and egg burden in infected BALB/c and C57BL/6 mice with dose- and time-dependent manners. Additionally, a dose- and time-dependent expression of IL-2, INF-γ, and TNF-α cytokines was also observed in both strains of mice treatments. Using T1/T2 doubly transgenic mice, we demonstrated that AB-PS-treated mice splenocytes initiated early differentiation of Th1 and NK1 cells, which was consistent with the reduction course of Schistosoma infection. Although AB-PS treatment enhanced the Th1 response, it did not suppress Th2 cell activity in treated mice. Histopathological data of the livers showed AB-PS treatment significantly attenuated the liver fibrosis induced by S. mansoni eggs. AB-PS augmented type-1 responses by inducing Th1 and NK1 cell differentiation to effectively decrease the infection rate of S. mansoni. Furthermore, AB-PS treatment may not only inhibit the schistosome infection, but also improving the pathological effects of granulomas formation. This study provides evidence for a novel therapeutic potential, by which A. blazei Murill may be used to treat or prevent schistosome infection.

A potential peptide derived from cytokine receptors can bind proinflammatory cytokines as a therapeutic strategy for anti-inflammation.

Chronic inflammation is a pivotal event in the pathogenesis of cardiovascular diseases, including atherosclerosis, restenosis, and coronary artery disease. The efficacy of current treatment or preventive strategies for such inflammation is still inadequate. Thus, new anti-inflammatory strategies are needed. In this study, based on molecular docking and structural analysis, a potential peptide KCF18 with amphiphilic properties (positively charged and hydrophobic residues) derived from the receptors of proinflammatory cytokines was designed to inhibit cytokine-induced inflammatory response. Simulations suggested that KCF18 could bind to cytokines simultaneously, and electrostatic interactions were dominant. Surface plasmon resonance detection showed that KCF18 bound to both tumor necrosis factor-α (TNF-α) and interleukin-6, which is consistent with MM/PBSA binding free energy calculations. The cell experiments showed that KCF18 significantly reduced the binding of proinflammatory cytokines to their cognate receptors, suppressed TNF-α mRNA expression and monocyte binding and transmigration, and alleviated the infiltration of white blood cells in a peritonitis mouse model. The designed peptide KCF18 could remarkably diminish the risk of vascular inflammation by decreasing plasma cytokines release and by directly acting on the vascular endothelium. This study demonstrated that a combination of structure-based in silico design calculations, together with experimental measurements can be used to develop potential anti-inflammatory agents.

An engineered arginine-rich α-helical antimicrobial peptide exhibits broad-spectrum bactericidal activity against pathogenic bacteria and reduces bacterial infections in mice.

The increase in the prevalence of antibiotic-resistant bacteria has become a major public health concern. Antimicrobial peptides (AMPs) are emerging as promising candidates addressing this issue. In this study, we designed several AMPs by increasing α-helical contents and positive charges and optimizing hydrophobicity and amphipathicity in the Sushi 1 peptide from horseshoe crabs. A neural network-based bioinformatic prediction tool was used for the first stage evaluations of peptide properties. Among the peptides designed, Sushi-replacement peptide (SRP)-2, an arginine-rich and highly α-helical peptide, showed broad-spectrum bactericidal activity against both Gram-positive and Gram-negative bacteria, including methicillin-resistant Staphylococcus aureus and multidrug-resistant Acinetobacter baumannii; nevertheless, it showed little hemolytic and cytotoxic activity against mammalian cells. Atomic force microscopy results indicated that SRP-2 should interact directly with cell membrane components, resulting in bacterial cell death. SRP-2 also neutralized LPS-induced macrophage activation. Moreover, in an intraperitoneal multidrug-resistant A. baumannii infection mouse model, SRP-2 successfully reduced the bacterial number in ascitic fluid and tumor necrosis factor-α production. Our study findings demonstrate that bioinformatic calculations can be powerful tools to help design potent AMPs and that arginine is superior to lysine for providing positive charges for AMPs to exhibit better bactericidal activity and selectivity against bacterial cells.

Highly potent antimicrobial modified peptides derived from the Acinetobacter baumannii phage endolysin LysAB2.

The increase in the prevalence of multidrug-resistant Acinetobacter baumannii (MDRAB) strains is a serious public health concern. Antimicrobial peptides (AMPs) are a possible solution to this problem. In this study, we examined whether AMPs could be derived from phage endolysins. We synthesized four AMPs based on an amphipathic helical region in the C-terminus of endolysin LysAB2 encoded by the A. baumannii phage ΦAB2. These peptides showed potent antibacterial activity against A. baumannii (minimum inhibitory concentration, 4-64 µM), including some MDR and colistin-resistant A. baumannii. Of the four peptides, LysAB2 P3, with modifications that increased its net positive charge and decreased its hydrophobicity, showed high antibacterial activity against A. baumannii but little haemolytic and no cytotoxic activity against normal eukaryotic cells. The results of electron microscopy experiments and a fluorescein isothiocyanate staining assay indicated that this peptide killed A. baumannii through membrane permeabilization. Moreover, in a mouse intraperitoneal infection model, at 4 h after the bacterial injection, LysAB2 P3 decreased the bacterial load by 13-fold in ascites and 27-fold in blood. Additionally, LysAB2 P3 rescued sixty percent of mice heavily infected with A. baumannii from lethal bacteremia. Our results confirmed that bacteriophage endolysins are a promising resource for developing effective AMPs.

Combined IL-12 Plasmid and Recombinant SjGST Enhance the Protective and Anti-pathology Effect of SjGST DNA Vaccine Against Schistosoma japonicum.

Schistosomiasis is listed as one of most important tropical diseases and more than 200 million people are estimated to be infected. Development of a vaccine is thought to be the most effective way to control this disease. Recombinant 26-kDa glutathione S-transferase (rSjGST) has previously been reported to achieve a worm reduction rate of 42-44%. To improve the efficiency of the vaccine against Schistosoma japonicum, we immunized mice with a combination of pcDNA vector-encoded 26-kDa SjGST (pcDNA/SjGST), IL-12 expressing-plasmid (pIL-12), and rSjGST. Co-vaccination with pcDNA/SjGST, pIL-12, and rSjGST led to a reduction in worm burden, hepatic egg burden, and the size of liver tissue granulomas than that in the untreated infection controls. In addition, we detected high levels of specific IgG, IgG1, and IgG2a against the rSjGST antigen in infected mice vaccinated with this combination of pcDNA/SjGST, pIL-12, and rSjGST. Moreover, high expression levels of Th2 cytokines, including IL-4 and IL-10, were also detected in this group, without diminished levels of IL-12, INF-γ, and TNF-α cytokines that are related to parasite killing. In conclusion, we have developed a new vaccination regimen against S. japonicum infection and shown that co-immunization with pcDNA/SjGST vaccine, pIL-12, and rSjGST has significant anti-parasite, anti-hepatic egg and anti-pathology effects in mice. The efficacy of this vaccination method should be further validated in large animals such as water buffalo. This method may help to reduce the transmission of zoonotic schistosomiasis japonica.

beta-Naphthoflavone protects from peritonitis by reducing TNF-alpha-induced endothelial cell activation.

ß-Naphthoflavone (ß-NF), a ligand of the aryl hydrocarbon receptor, has been shown to possess anti-oxidative properties. We investigated the anti-oxidative and anti-inflammatory potential of ß-NF in human microvascular endothelial cells treated with tumor necrosis factor-alpha (TNF-α). Pretreatment with ß-NF significantly inhibited TNF-α-induced intracellular reactive oxygen species, translocation of p67(phox), and TNF-α-induced monocyte binding and transmigration. In addition, ß-NF significantly inhibited TNF-α-induced ICAM-1 and VCAM-1 expression. The mRNA expression levels of the inflammatory cytokines TNF-α and IL-6 were reduced by ß-NF, as was the infiltration of white blood cells, in a peritonitis model. The inhibition of adhesion molecules was associated with suppressed nuclear translocation of NF-κB p65 and Akt, and suppressed phosphorylation of ERK1/2 and p38. The translocation of Egr-1, a downstream transcription factor involved in the MEK-ERK signaling pathway, was suppressed by ß-NF treatment. Our findings show that ß-NF inhibits TNF-α-induced NF-kB and ERK1/2 activation and ROS generation, thereby suppressing the expression of adhesion molecules. This results in reduced adhesion and transmigration of leukocytes in vitro and prevents the infiltration of leukocytes in a peritonitis model. Our findings also suggest that ß-NF might prevent TNF-α-induced inflammation.

A study of immunomodulatory genes responses to macrophages of Schistosoma japonicum infection during different stages by microarray analysis.

Macrophages initiate, modulate, and also serve as final effector cells in immune responses during the course of schistosomal infections. In this study, we investigated the gene expression profile and functional changes of macrophages in immune responses against the Schistosoma japonicum by microarray analysis. Hierarchical clustering analysis demonstrated that a significant switch in gene transformation associated with a type-1 response and linked with a type-2 cytokine phenotype occurs between 4.5 and 8 weeks post-infection. Moreover, the gene profiles at 3 later time-points following egg challenge were similar in complexity and magnitude. The data also showed that there were mostly inhibition of gene expression related TLR, IFN, MHC and TNFrsf at the switch between 4.5 and 8 weeks post-infection, It is suggested that these immunomodulatory genes may be down-regulated in defense against S. japonicum eggs and granuloma pathology. The induction of alternatively activated macrophage (AAMϕ) was important for dampening the inflammation in hepatic granulomas and contributing to a decrease in cytotoxicity. The gene expressions involved in repair/remodeling during liver fibrosis were also observed after egg production. Understanding the immune mechanisms associated with parasitic resistance, pathology of parasite infection, and parasite growth will provide useful insight on host-schistosome interactions and for the control of schistosomiasis.

Occurrence and genotype of Giardia cysts isolated from faecal samples of children and dogs and from drinking water samples in an aboriginal area of central Taiwan.

To investigate some aspects of Giardia infection, we performed a cross-sectional study on schoolchildren from an aboriginal area of Nantou County in central Taiwan. Faecal samples from 209 participants and samples of dog faeces and of water from mountain springs found in the area were collected. The participants also filled a questionnaire pertaining to demographic data. Giardia duodenalis was detected in eight of the 209 participants, and all positive isolates belonged to assemblage A. In addition, assemblage A isolates were obtained from four of the 22 water samples, and assemblage C or D isolates were obtained from four of the 42 canine faecal samples. Our results suggest that the risk of Giardia transmission is greater from waterborne than canine transmission in this study area.

Infection of normal C3H/HeN mice with Taenia saginata asiatica oncospheres.

Normal C3H/HeN female mice were used to develop an animal model of Taenia saginata asiatica oncosphere infection. The host cellular immune response in this model was analyzed by a cytokine enzyme-linked immunosorbent assay (cytokine ELISA) and flow cytometry. Tumor-like cysts containing cysticerci were recovered from the inoculation sites of female mice 7 weeks postinfection with the T. saginata asiatica oncospheres. A sharp increase and sustained elevation in the ability of spleen cells to produce interferon-gamma and interleukin (IL)-2 revealed that cellular immunity played an important role during the infection. An immediate increase in the levels of IL-6 at 1 week postinfection indicated the induction of a local acute inflammatory response. However, no significant change in the levels of IL-10 indicated that Th2 cells were not involved in this immune response. The patterns of cell distribution revealed by flow cytometry also supported the same finding. These results suggested that Th1 cells played a major role in the immune response in C3H/HeN mice during the early stages of the oncosphere infection and that the Th2 response was not induced during the stage of cysticercus formation.