No abstract

No abstract

Animal Leptospirosis, caused by Leptospira spp., is one of the most common zoonotic diseases in the US and throughout the world. Commercially available bacterins are only partially efficacious in that they protect against death, but not against disease. Protective immunity to Leptospira spp. require antibodies specific to outer surface proteins and/or adhesins of leptospires. Spirochetes produce membrane blebs or vesicles (OMVs) and OMVs have been shown to be good immunogens. In this study, we characterized leptospiral OMV components by liquid chromatography-tandem mass spectrometry (LC-MS/MS) analysis of and identified that the majority (58.1%) of proteins in the vesicles were cytoplasmic proteins (294 of 506), while 5 were extracellular proteins (0.99%), 11 were outer membrane proteins (2.17%), 14 were periplasmic proteins (2.77%), 48 were cytoplasmic/inner membrane proteins (9.49%) and 134 were unknown or having multiple locations (26.48%). Transmission electron microscopy (TEM) imaging showed OMVs are spherical bodies with a diameter of 50-200 nm. Vesicles were used to vaccinate hamsters. The results indicated that immunization with Leptospira OMVs induced significant protection against lethal challenge revealed by an enhanced humoral immune response, high survival rate and significantly reduced bacterial burden, all of which were reflected in decreased pulmonary, hepatic and renal lesions (p<0.05). To the best of our knowledge, this is the first report showing that OMVs could be used as a novel vaccine formulation to protect hamsters against lethal challenge.

BACKGROUND: Patients infected with a parasite often develop opisthorchiasis viverrini, which often progresses into cholangiocarcinoma (CCA) due to the asymptomatic nature of the infection. Currently, there are no effective diagnostic methods for opisthorchiasis or cholangiocarcinoma. OBJECTIVE: The aim of this study was to identify the host-responsive protein that can be developed as a diagnostic biomarker of opisthorchiasis and cholangiocarcinoma. METHODS: Plasma samples were collected from non-OVCCA, OV, and CCA subjects, and the proteomes were investigated by LC-MS/MS. Venn diagrams and protein network prediction by STITCH were used to identify the potential biomarkers. The level of candidate protein, the plasma checkpoint protein 1 (Chk1), was measured by indirect enzyme-linked immunosorbent assay (ELISA). RESULTS: Chk1 was present in the center of the protein network analysis in both the OV and CCA groups. In addition, the plasma Chk1 levels were significantly increased in both groups (P< 0.05). The sensitivity of the opisthorchiasis viverrini and cholangiocarcinoma was 59.38% and 65.62%, respectively, while the specificity of both was 85.71%. CONCLUSION: Chk1 was identified by differential plasma proteomes and was increased in O. viverrini-infected and cholangiocarcinoma-derived plasma samples. Higher levels of plasma Chk1 levels may serve as a potential diagnostic biomarker for opisthorchiasis and cholangiocarcinoma.

The human liver fluke Opisthorchis viverrini (Ov), the primary risk factor for cholangiocarcinoma (CHCA), is a parasite endemic to southeast Asian countries. With no effective treatments for CHCA currently available, early diagnosis and treatment of Ov infection remains the only practical method for the prevention of CHCA. In this study, plasma phosphoproteomes of patients in the non-Ov infection, non-cholangiocarcinoma subject group (non-OVCCA), the asymptomatic Ov infected group (OV), and the CHCA group (CCA), were investigated to identify potential biomarkers for Ov infection and CHCA. The AKT signalling pathway was found to be up-regulated. Phosphatidylinositol 4,5-bisphosphate 3-kinase catalytic subunit beta isoform (PIK3CB), an upstream signalling molecule, was selected as a potential biomarker and evaluated using indirect enzyme-linked immunosorbent assay (ELISA). Results demonstrated evidence that levels of PIK3CB in both the OV group and CCA group was statistically different compared to the non-OVCCA group (P < 0.01). However, the levels of PIK3CB between the OV group and the CCA group were found not to be statistically different. Sensitivity and specificity for OV using OD450 cut-off at >1.570 was 76 and 72%, respectively. For CCA, sensitivity and specificity using OD450 cut-off at >1.398 was 68 and 76%, respectively. Application of indirect ELISA detecting plasma PIK3CB will be of great benefit for screening of opisthorchiasis and CHCA.