In a short time, West Nile virus has developed into a nationwide health and veterinary problem. The high virulence of the circulating virus and related lineage 1 WN strains hinders development of an attenuated live vaccine. We describe an attenuated WN isolate, WN1415, which is a molecularly cloned descendant of the WN prototype B956 strain. The parent virus belongs to lineage 2, members of which have not been associated with epidemic or epizootic outbreaks. A set of non-conservative mutations, mostly in non-structural protein genes, distinguishes the WN1415 isolate from the parent B956 prototype strain. Immunization with WN1415 (55-550,000 pfu) established a potent immunity, which protected the majority of mice against lethal challenge with WN NY99. The attenuated nature of the isolate and its excellent growth characteristics combined with the availability of a highly stable infectious clone make the isolate an attractive candidate for live WN vaccine development.

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The exceptionally high virulence of the West Nile NY99 strain makes its suitability in the development of a live WN vaccine uncertain. The aim of this study is to investigate the immunogenicity of noninfectious virus derivatives carrying pseudolethal mutations, which preclude virion formation without affecting preceding steps of the viral infectious cycle. When administered using DNA immunization, such constructs initiate an infectious cycle but cannot lead to a viremia. While the magnitude of the immune response to a noninfectious replication-competent construct was lower than that of virus or infectious DNA, its overall quality and the protective effect were similar. In contrast, a nonreplicating construct of similar length induced only a marginally detectable immune response in the dose range used. Thus, replication-competent noninfectious constructs derived from infectious DNA may offer an advantageous combination of the safety of noninfectious formulations with the quality of the immune response characteristic of infectious vaccines.

Aim. Comparison of effectiveness of solid phase methods of immune detection of botulinic toxin in blood sera of a patient with botulism diagnosis: dot-immune assay using specific anti-botulinic antibodies (AT) labeled with nanoparticles of colloid silver, phosphorescent analysis (PHOSPHAN) using streptavidin label with platinum coproporphyrin (PtCP) and polystyrene nanoparticles, containing chelate complex of europium ions with naphthoyl trifluoroacetone (NA-Eu). Materials and methods. Silver nanoparticle labeled IgG isolated from a commercial diagnostic polyvalent sera against type А, В, С, E, F botulotoxins manufactured by SPA Allergen (Stavropol) with 5000 - 10000 IU activity and biotin conjugated commercial monoclonal antibodies against botulotoxin A, polyclonal mono-specific AB against botulotixin В and E and polyvalent immunoglobulin against botulotoxin А, В, С, E, F. Detection ofbotulotoxin in clinical material was carried out in dot-immunoassay on nitrocellulose membrane by PHOSPHAN method in an experimental test system using 2 detector systems based on streptavidin: PtCP and NA-Eu. Results. Botulotoxin was detected in blood sera of the botulism patient using both of the developed immune detection methods. PHOSPHAN method allowed to identify serotype В botulotoxin, that corresponded with the results obtained in botulotoxin biological neutralization reaction. Sensitivity of PHOSPHAN with NA-Eu luminescent nanoparticle based detection system was higher than with PtCP label. Conclusion. The developed methods (PHOSPHAN and dot-immunoassay) differ by high specificity and sensitivity and may be recommended for express detection of botulinic toxin in clinical material.