To find an effective mucosal adjuvant for influenza virus-like particles (VLPs), we compared the effects of known adjuvants Alum, CpG DNA, monophosphoryl lipid A (MPL), poly IC, gardiquimod, and cholera toxin (CT). Mice that were intranasally immunized with Alum, CpG, MPL, and CT adjuvanted VLPs showed higher levels of antibodies in both sera and mucosa. Hemagglutination inhibition and virus neutralizing activities were enhanced in groups adjuvanted with Alum, MPL, or CT. Influenza virus specific long-lived cells secreting IgG and IgA antibodies were found at high levels both in bone marrow and spleen in the Alum, CpG and CT adjuvanted groups. A similar level of protection was observed among different adjuvanted groups, except the CT adjuvant that showed a higher efficacy in lowering lung viral loads after challenge. Alum and CT adjuvants differentially increased influenza VLP-mediated activation of dendritic cells and splenocytes in vitro, supporting the in vivo pattern of antibody isotypes and cytokine production. These results suggest that Alum, MPL, or CpG adjuvants, which have been tested clinically, can be developed as an effective mucosal adjuvant for influenza VLP vaccines.

ABSTRACT. The main complications of clonorchiasis are periportal inflammation, biliary hyperplasia, periductal fibrosis, and subsequently the development of biliary tumors in the liver. This study was undertaken to compare the infectivity and histopathologic changes between in immunocompetent FVB/NJ and BALB/cA strains, and immunodeficient severe combined immunodeficient (SCID) and athymic nude mice after the metacercariae of Clonorchis (C.) sinensis were infected. The experiment showed that C. sinensis was very infective in all strains studies, but the status of worm development, infectivity, recovery rate, and morphological changes of livers were very different in each strain. FVB/NJ mice showed more worm recovery than any other strain. Histopathologically the liver of FVB/NJ mice at 4 weeks postinfection showed marked cystic and fibrotic changes, in which C. sinensis was fully developed with ovum production, severe infiltration of inflammatory cells, mostly eosinophils, and high degrees of biliary hyperplasia. In SCID and nude mice, there were few foci of inflammatory cells even at 8 weeks postinfection in periportal areas of the liver, associated with no development into adult worm with ovum production. Fibrosis occurring at 4 weeks postinfection was highly correlated with inflammatory infiltration when each strain was compared. We suggest that massive infiltration of eosinophil and plasma cells caused by the infection might initiate cystic formation and fibrosis. These data demonstrate that the infection of C. sinensis might be related to pathologic consequences of inflammatory cell infiltration, cystic formation and fibrosis which might play a role in the defense mechanism against the parasitism in the liver of each strain. The FVB/NJ mouse model might be very helpful in elucidating the mechanism for human clonorchiasis.

Although co-infection with multiple parasites is a frequent occurrence, changes in the humoral immune response against a pre-existing parasite induced as a result of a subsequent parasitic infection remain undetermined. Here, we utilized enzyme-linked immunosorbent assay (ELISA) to investigate antibody responses, cytokine production and enhanced resistance in Clonorchis sinensis-infected rats (Sprague-Dawley) upon Trichinella spiralis infection. Higher levels of C. sinensis-specific IgG and IgA were elicited upon T. spiralis infection, and these levels remained higher than in rats infected with C. sinensis alone. Upon subsequent infection with T. spiralis, IgG antibodies against C. sinensis appeared to be rapidly boosted at day 3, and IgA antibodies were boosted at day 7. Challenge infection of C. sinensis-infected rats with T. spiralis induced substantial mucosal IgG and IgA responses in the liver and intestine and increases in antibody-secreting plasma cells in the spleen and bone marrow. Subsequent infection also appeared to confer effective control of liver C. sinensis loads, resulting in enhanced resistance. Memory B cells generated in response to C. sinensis infection were rapidly amplified into antibody-secreting cells upon T. spiralis infection. These results indicate that enhanced C. sinensis clearance induced by co-infection is associated with systemic and mucosal IgG and IgA responses.

The present study was undertaken to determine the acceptablility, tolerance and effectiveness of praziquantel in a rural population infected with Clonorchis sinensis and to suggest the suitable dosages of praziquantel for the field use on a large scale. A total of 121 patients with proven C. sinensis infection were treated by two dosages with praziquantel at a single dose of 40 mg/kg bwt and 2 doses of 30 mg/kg bwt in a single day. A single dose of 40 mg/kg bwt were given to 60 patients and 2 x 30mg/kg bwt were given to 61 patients. Follow-up examinations were carried out at about 30 and 60 days after treatment. Two months after therapy, 13(21.7%) of 60 patients who received a single dose of 40 mg/kg bwt were cured completely. Among these cured patients, 9(75.0%) out of 12 cases of light and only 4 out of 48 cases of moderate or heavy infection groups were cured. But in the non-cured cases the overall egg reduction rate was 89.1%. On the other hand, 36(59.0%) out of 61 patients treated with 2 x 30 mg/kg bwt were cured at 60 days after treatment. Among these cured patients, all of the 13 cases of light infection and 18(69.2%) out of 26 cases of moderate and 5(23.8%) out of 21 cases of heavy infection groups were cured completely at 60 days after therapy. However the overall egg reduction rate was 95.2% in the non-cured cases. Praziquantel is well tolerated and side effects consist particularly of mild and transient headache, dizziness and abdominal discomfort, etc. However there was no difference in regard to frequency and intensity of untoward side effects between the two dosage groups. The results obtained in this study suggest that a single dose of 40 mg/kg bwt for light infection, 2 x 30 mg/kg bwt for moderate infection and 3 x 25 mg/kg bwt for heavy infection groups will be recommended for the field use on a large scale.

Summary:Efficacy of flubendazole and albendazole against Trichinella spiralis in mice were studied. ICR mice were experimentally infected with Trichinella spiralis and treated with either flubendazole (FBZ) or albendazole (ABZ) at four different stages of the parasite life-cycle. Oral administration of either FBZ or ABZ at 20 mg/kg and 50 mg/kg on 2 h, 8 h and 24 h (pre-adult stage) after infection eliminated 94.7 -100 % of adults as determined at necropsy on day 7 post infection (p.i.) and 96.9 ~ 100 % of larvae on day 45 p.i. FBZ was more effective than ABZ against adult T. spiralis (at 2 to 6 days p.i.), when treated with a dosage of 20 mg/kg for 5 consecutive days (99.4 % and 46.0 % reduction with respect to the control group). Against migrating larval T. spiralis, FBZ was more effective than ABZ at 20 mg/kg for five consecutive days (on days 11̰15 p.i.), and the reduction rate of recovered larvae were 99.6 % (FBZ) and 80.8 % (ABZ) respectively. FBZ was more effective against early encapsulated larval T. spiralis (at 21 to 25 days p.i.), than ABZ when both were given at 20 mg/kg for five consecutive days (99.8 % and 45.4 % reduction, respectively). In conclusion, flubendazole was more effective than albendazole against adult and parenteral stages of Trichinella spiralis in mice. bell & Cuckler, 1964;Duckett & Denham, 1970;Spaldonova et al., 1974;Fernando & Denham, 1976;Lopez-Garcia et al., 1997). It was demonstrated that mebendazole was highly effective against the immature enteral phase of trichinosis in mice (Fernando & Denham, 1976;McCracken, 1978). McCracken (1978) reported that albendazole was much more effective against pre-adult and had a partial effect on adult KEY WORDS : RECOVERY OF WORMSThe number of enteral Trichinella in each group of mice was estimated seven days after exposure to infection. At necropsy, each mouse was examined individually for adult worms from gut. All the mice treated with drugs against migrating and early encapsulated muscle larval stage were killed 45 days post infection (p.i.) and the number of diaphragm larvae was counted.Parasite, 2001, 8, S195-S198