Qi Xin

Efficacy of osthole for Echinococcus granulosus in vitro and Echinococcus multilocularis in vivo

Echinococcosis is a zoonotic infection caused by cestode species of the genus Echinococcus; in addition, this zoonosis has long been neglected as a parasitic disease and has limited treatment options. Clinical drugs such as benzimidazole derivatives have limited treatment efficacy. The current study evaluated a novel drug, osthole, with low toxicity and high activity against Echinococcus in vitro and in vivo. The results in vitro indicated that the viability of Echinococcus granulosus protoscoleces in the group treated with osthole (120μM) decreased by 100% within 3days. In vivo experiments were conducted using parasite-infected mice. For this purpose, three groups of infected mice were treated daily for 6 weeks with albendazole (ABZ, 100mg/kg, positive control group), osthole (100mg/kg, experimental group), or honey/PBS (100mg/kg, negative control group), respectively. The osthole- and ABZ-treated groups presented a significant reduction in wet weight of metacestodes, increase in the level of interleukin (IL)-4 and the percentage of eosinophils compared with the control group. Osthole exhibited a high activity against echinococcosis in vivo. In addition, the toxicity of osthole was evaluated via an in vitro 3-(4,5)-dimethylthiahiazo(-z-y1)-3,5-di-phenytetrazoliumromide (MTT) assay, as well as via morphological observation and calculation of liver and kidney function indexes in vivo. No obvious toxic effects of osthole were observed in our study. Therefore, this novel drug may be a promising alternative to benzimidazole in anti-echinococcosis chemotherapy.

A Newly Discovered Epidemic Area of Echinococcus multilocularis in West Gansu Province in China

Alveolar echinococcosis (AE) is a lethal parasitic disease. In Gansu Province of China, all AE cases reported in literature were from Zhang and Min Counties, the southern part of the province. Here, we report the discovery of nine AE cases and one cystic echinococcosis (CE) case from Nanfeng Town of Minle County, in the middle of Hexi Corridor in west Gansu Province. The diagnosis of these cases were confirmed by serology, histopathology, computed tomography, B-ultrasound, immunohistochemistry method, DNA polymerase chain reaction and sequencing analysis. Because eight of nine AE cases came from First Zhanglianzhuang (FZLZ) village, we conducted preliminary epidemiological analyses of 730 persons on domestic water, community and ecology such as 356 dogs’ faeces of FZLZ, in comparison with those of other five villages surrounding FZLZ. Our studies indicate that Nanfeng Town of Minle County is a newly discovered focus of AE in China as a CE and AE co-epidemic area. Further research of Echinococcus multilocularis transmission pattern in the area should be carried for prevention of this parasitic disease.

Immunogenicity and protective efficacy of multistage vaccine candidates (Mtb8.4-HspX and HspX-Mtb8.4) against Mycobacterium tuberculosis infection in mice

Abstract In this study, Mtb8.4 and HspX, which are expressed at proliferating and dormant stages of Mycobacterium tuberculosis (M. tuberculosis), respectively, were chosen to construct two fusion proteins, Mtb8.4‐HspX (8.4H) and HspX‐Mtb8.4 (H8.4), and we investigated whether the antigen dose and protein sequential order could impact the immunogenicity and protective efficacy of these fusion protein vaccines against M. tuberculosis. C57BL/6 mice were vaccinated with new constructions containing a fusion protein with adjuvant of N, N′‐dimethyl‐N, N′‐dioctadecylammonium bromide (DDA) or a mixed adjuvant composed of DDA, polyribocytidylic acid and gelatin (DPG), and the antigen specific immune responses and protective efficacy against M. tuberculosis H37Rv were evaluated. The results showed that both antigens, Mtb8.4‐HspX and HspX‐Mtb8.4, could elicit strong human T cell responses. With the existing of DDA adjuvant, HspX‐Mtb8.4 induced significantly higher secretion level of IFN‐&ggr; and TNF‐&agr; in spleen cells than Mtb8.4‐HspX (p < 0.05). In its protective efficacy study, the isolated bacterial Colony Form Unit (CFU) in H8.4‐DPG group was significantly reduced compared to 8.4H–DPG group (p < 0.05). Furthermore, with the stimulation of Mtb8.4 in vitro, the secretion of IFN‐&ggr; and TNF‐&agr; from mice immunized with 20 &mgr;g of H8.4 exhibited relative higher level than the group immunized by 7 &mgr;g of H8.4 (p < 0.05), whereas, IL‐2 secreting showed contrary result. The data suggest that the antigen sequential order and dose selection should be considered when a tuberculosis protein vaccine is to be constructed and its immune strategy is to be planned. HighlightsWe constructed two novel TB subunit vaccine candidate Mtb8.4‐HspX and HspX‐Mtb8.4.Mtb8.4‐HspX and HspX‐Mtb8.4 with reversed organization.Mtb8.4‐HspX and HspX‐Mtb8.4 have different immunogenicity and protective efficacy.