Effects of subchronic exposure to Successor 600 (pethoxamid 600 g L-1) on common carp Cyprinus carpio.

OBJECTIVES: We investigated the effects of the herbicide preparation Successor 600 on biochemical and haematological indices and the histolopathological parameters of common carp after 28 day exposure. Furthermore, the hepatosomatic index and induction of xenobiotic metabolizing enzymes and biomarkers were assessed. DESIGN: Juvenile fish were exposed to sublethal concentrations of Successor(R) 600 (0.06 mg L-1, 0.22 mg L-1 or 0.60 mg L-1) for 28 days. Haematological indices were assessed using unified methods of haematological examination in fish. Plasma biochemical indices were measured by biochemical analyzer, the vitellogenin concentration in male fish plasma was estimated by direct sandwich ELISA. In hepatopancreas, ethoxyresorufin-O-deethylase (EROD) activity was measured spectrofluorimetrically, concentration of total cytochrome P450 (CYP), glutathion (GSH) content and glutathion-S-transferase (GST) activity were determined spectrophotometrically. Histological changes in samples of hepatopancreas, skin, gills, spleen, head kidney and trunk kidney were examined by light microscopy. RESULTS: Haemoglobin, MCH and MCHC were significantly (p<0.05) reduced in fish treated with Successor(R) 600 of 0.22 and 0.60 mg L-1. LDH was enhanced (p<0.05), in the highest concentration of the preparation. Vitellogenin was detected in all male fish, with no difference between groups. HSI, GSH and GST were elevated (p<0.05), owing to the exposure, whereas CYP and EROD were not affected. Slight histopathological changes were demonstrated in skin, gills and hepatopancreas, with steroid tissue in head kidney samples of 0.60 mg L-1 treated fish. CONCLUSION: Successor 600 affected the haematological profile of the treated fish, while the effects on biochemical indices were less expressed. Male plasma vitellogenin concentrations were not indicative of estrogen disruptive effects after 28 days. The importance of GSH and GST for the metabolisation were demonstrated. In contrast, CYP and EROD were not influenced by any concentration tested. HSI was found to reflex pollution with Successor 600. Histopathological indices caused by the treatment were observed in various tissue samples of the treated fish.

Preclinical evaluation of a replication-deficient intranasal DeltaNS1 H5N1 influenza vaccine.

BACKGROUND: We developed a novel intranasal influenza vaccine approach that is based on the construction of replication-deficient vaccine viruses that lack the entire NS1 gene (DeltaNS1 virus). We previously showed that these viruses undergo abortive replication in the respiratory tract of animals. The local release of type I interferons and other cytokines and chemokines in the upper respiratory tract may have a "self-adjuvant effect", in turn increasing vaccine immunogenicity. As a result, DeltaNS1 viruses elicit strong B- and T- cell mediated immune responses. METHODOLOGY/PRINCIPAL FINDINGS: We applied this technology to the development of a pandemic H5N1 vaccine candidate. The vaccine virus was constructed by reverse genetics in Vero cells, as a 5:3 reassortant, encoding four proteins HA, NA, M1, and M2 of the A/Vietnam/1203/04 virus while the remaining genes were derived from IVR-116. The HA cleavage site was modified in a trypsin dependent manner, serving as the second attenuation factor in addition to the deleted NS1 gene. The vaccine candidate was able to grow in the Vero cells that were cultivated in a serum free medium to titers exceeding 8 log(10) TCID(50)/ml. The vaccine virus was replication deficient in interferon competent cells and did not lead to viral shedding in the vaccinated animals. The studies performed in three animal models confirmed the safety and immunogenicity of the vaccine. Intranasal immunization protected ferrets and mice from being infected with influenza H5 viruses of different clades. In a primate model (Macaca mulatta), one dose of vaccine delivered intranasally was sufficient for the induction of antibodies against homologous A/Vietnam/1203/04 and heterologous A/Indonesia/5/05 H5N1 strains. CONCLUSION/SIGNIFICANCE: Our findings show that intranasal immunization with the replication deficient H5N1 DeltaNS1 vaccine candidate is sufficient to induce a protective immune response against H5N1 viruses. This approach might be attractive as an alternative to conventional influenza vaccines. Clinical evaluation of DeltaNS1 pandemic and seasonal influenza vaccine candidates are currently in progress.