Plasma IgG autoantibody against actin-related protein 3 in liver fluke Opisthorchis viverrini infection.

Opisthorchiasis secondary to Opisthorchis viverrini infection leads to cholangiocellular carcinoma through chronic inflammation of the bile ducts and possibly inducing autoimmunity. It was hypothesized that plasma autoantibodies directed against self-proteins are biomarkers for opisthorchiasis. Plasma from patients with opisthorchiasis was tested using proteins derived from immortalized cholangiocyte cell lines, and spots reacting with plasma were excised and subjected to LC-MS/MS. Seven protein spots were recognized by IgG autoantibodies, and the highest matching scored protein was actin-related protein 3 (ARP3). The antibody against ARP3 was tested in plasma from 55 O. viverrini-infected patients, 24 patients with others endemic parasitic infections and 17 healthy controls using Western blot and ELISA. Immunoreactivity against recombinant ARP3 was significantly more prevalent in opisthorchiasis compared to healthy controls at Western blotting and ELISA (P < 0.05). Plasma ARP3 autoantibody titres were also higher in opisthorchiasis compared to healthy individuals (P < 0.01) and other parasitic infections including Strongyloides stercoralis (P < 0.001), echinostome (P < 0.05), hookworms (P < 0.001) and Taenia spp. (P < 0.05). It was further characterized in that the ARP3 autoantibody titre had a sensitivity of 78.18% and specificity of 100% for opisthorchiasis. In conclusion, it may be suggested that plasma anti-ARP3 might represent a new diagnostic antibody for opisthorchiasis.

Proteomic identification of peroxiredoxin 6 for host defence against Opisthorchis viverrini infection.

Opisthorchis viverrini infection causes opisthorchiasis and is a risk factor for cholangiocarcinoma via chronic inflammation. To investigate the mechanism of O. viverrini -induced liver disease, we applied a proteomic approach to examine alterations in hepatic protein levels in O. viverrini -infected hamsters. Two-dimensional gel electrophoresis (2DE) revealed that O. viverrini infection induced upregulation (1.5- to 4.3-fold) of 25 proteins and downregulation (1.5 to 2.5-fold) of 24 proteins compared with uninfected animals. Expression of proteins related to stress response, DNA replication and repair, and cell structure was significantly increased, whereas that of proteins associated with normal liver function, such as metabolism, blood volume maintenance and fatty acid cycle was decreased. Among the upregulated proteins, a 2.7-fold increase in peroxiredoxin 6 (Prdx6), an antioxidant protein, was confirmed by 2DE and immunoblot analysis, Western blot and quantitative PCR. Immunohistochemical analysis showed that Prdx6 expression was observed mainly in the cytoplasm of inflammatory cells. These results suggest that Prdx6 is important for host defence against O. viverrini infection. This study provides basic information for Prdx6 as a potential biomarker and therapeutic target for opisthorchiasis.

Apoptosis-related gene expression in hamster opisthorchiasis post praziquantel treatment.

The aim of this study was to investigate the apoptosis-related gene expression in hamster opisthorchiasis after praziquantel treatment. Hamsters were infected with Opisthorchis viverrini metacercariae then treated with praziquantel. The expression of apoptosis-related genes [i.e., apoptosis gene Bcl-2-associated protein X (BAX), caspase 9, p53, and protein kinase B (PKB)] was detected by real-time reverse transcription polymerase chain reaction. Histopathological analyses of liver tissues were studies by staining the sections with hematoxylin and eosin using light microscopy. Apoptotic assay was used to localize the apoptotic cell death. The results show that BAX, Akt/PKB, p53, and caspase 9 expression level were significantly increased on day 30 post infection and at 6 h post treatment and gradually decreased nearly to the uninfected control and 24 h post treatment, perhaps due to a decrease in inflammatory cells. Apoptotic staining was positive reaction at inflammatory cells and nuclei of epithelial bile ducts. Although using praziquantel has an advantage in killing parasites, our results show the effect of praziquantel treatment from host immune response that induces increased apoptosis-related genes in the short term due to an increase in inflammatory cells surrounding the bile ducts.

Seroprevalence of specific total immunoglobulin (Ig), IgG and IgM antibodies to Toxoplasma gondii in blood donors from Loei Province, Northeast Thailand.

A total samples from 345 healthy blood donors from Loei Province, Northeast Thailand were examined for anti-Toxoplasma gondii antibodies by ELISA. The seroprevalence of the anti-Toxoplasma gondii total Ig, IgG and IgM antibodies was 4.9%, 4.1% and 4.3%, respectively. Overall seropositive rate was 33 out of 345 individuals (9.6%). Among the seropositve cases, 5 (15.2%), 2 (6.1%) and 13 (39.4%) of the samples were determined by using each type of anti-T. gondii total Ig, IgG and IgM antibodies, respectively. The seropositive sera was also determined by combining of anti-T. gondii antibodies (anti-T. gondii total Ig with IgG and anti-T. gondii total Ig with IgM antibodies). These results were 10 (30.3%) and 2 (6.1%) cases, respectively. Only one (3%) sample had all types of anti-T. gondii antibodies. In addition, the frequency distribution curves of ELISA optical densities of anti-T. gondii total Ig, IgG and IgM antibodies in blood donor presented "unimodal" curves. The negative results were found in the age group that less than 20 years old and more than 51. The highest seropositive results were found in two age groups (21-30 and 31-40 years old), and males were significantly higher than female (p < 0.05). These results demonstrated that when using anti-T. gondii total Ig, IgG and IgM antibodies for determining the seroprevalence, the sensitivity was twice that with the anti-T. gondii, total Ig antibody alone.