Rapid Detection of Orthopoxviruses

The aim of the study was to develop a sensitive and fast immunochemical test for the detection of orthopoxviruses (OPXV) in the “point of care” format.Materials and methods. The analyses were performed in cultured crude and purifed preparations of vaccinia virus, cowpoxvirus, rabbitpoxvirus and ectromelia virus, as well as in the blood and tissue suspensions of infected mice and rabbits. OPXV-antigen was detected by one-stage and two-stage protocols of dot-immunoassay based on flat protein arrays using rabbit polyclonal antibodies as capture and detection reagents.Results and discussion. The results show that the detection limit of OPXV is inversely related to the degree of their purifcation. The one-stage (rapid) protocol is specifc and allows detecting OPXV in crude culture samples of the virus and in clinical samples in the range of 104–103 PFU/ml within 39 minutes. Rapid dot-immunoassay can be applied to detect or exclude the presence of a viral threat in samples and can be useful in various aspects of biosafety provision. The simplicity of the one-stage protocol, the possibility to visually account the results and easy interpretation of the results allow the rapid test to be used in the “point of care” format.

Development of a horseradish peroxidase-nanobody fusion protein for visual detection of ochratoxin A by dot immunoassay

The horseradish peroxidase-nanobody fusion protein was developed as a promising immunological diagnostic reagent for toxic low-molecular-weight compounds in food.

Development of the scheme of obtaining antibodies to the ribonucleoprotein of attenuated rabies virus

Aim. Isolation of ribonucleoprotein (RNP) of an attenuated rabies virus, develop schemes for immunizing animals with RNP-based preparations and determine the most effective scheme that allows obtaining serum with a high antibody titer to the RNP.Materials and methods. We used the transplantable cell line Vero, the strain rabies virus «Moscow 3253 Vero», adapted for reproduction on Vero, rabbits of the chinchilla breed. In order to obtain serums containing antibodies to the RNP of the rabies virus, experimental schemes have been proposed for immunizing animals with RNP, including with adjuvants: polyoxidonium and colloidal gold. The dynamics of the accumulation of antibodies to the RNP of the rabies virus in the blood serum of experimental animals was studied by dot-immunoassay.Results. The target component (RNP of the rabies virus) was isolated directly from the cytoplasm of the Vero cell culture infected with the rabies virus according to the modified M. Dastkhosh (2014) method, lyophilized and used in the development of preparations for immunizing experimental animals. In the study of the dynamics of the formation of antibodies to RNP of the rabies virus by the method of dot-immunoassay, the effectiveness of an adjuvant is established — colloidal gold nanoparticles ranging in size from 15 to 17 nm, the use of which makes it possible to increase the antibody titer by 2 times.Conclusion. The results obtained are of interest for further research related to the design of diagnostic products and the development of methodological techniques using such preparations.

Visual dual dot immunoassay for the simultaneous detection of kanamycin and streptomycin in milk

Dual dot immunoassay for the simultaneous detection of kanamycin and streptomycin with visible readout in milk.

COMPARATIVE ANALYSIS OF EFFECTIVENESS OF SOLID-PHASE METHODS OF IMMUNE DETECTION OF BOTULINIC TOXIN IN BLOOD SERA OF A PATIENT WITH BOTULISM DIAGNOSIS

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.

DOT-IMMUNOASSAY USING GOLD NANOPARTICLE MARKED COLLOID GOLD FOR THE DETECTION OF BOTULINIC TOXIN IN CLINICAL MATERIAL AND FOOD PRODUCTS

Aim. Construction of test-systems for dot-immunoassay using colloid gold nanoparticles as a marker of specific antibodies for the detection of botulinic toxin in clinical material and food products. Materials and methods. 20 nm gold nanoparticles were used as a marker of specific antibodies. IgGs were isolated from polyvalent diagnostic sera against type А, В, С, E, F botulin toxins produced by SPC Allergen (Stavropol) with 5000 - 10 000 ME activity. Botulin toxin in clinical material (blood sera) from 3 patients with established botulism clinical diagnosis as well as food product (home-made mushroom soup solyanka) was determined by dot immunoassay on nitrocellulose membrane. Results. Botulin toxin was detected in all the studied samples (blood sera from 3 patients and the soup) that was registered in the patient No. 1 at the 1:2112 dilution of fhe studied sample, in patient No. 2 - 1:32, in patients No. 3 - 1:1056, in the food product - 1:8. Botulin toxin was not detected in the negative control (pure cultures of the dysentery cauzative agents and intestine yersinosis, blood sera of the patient with All and a healthy individual as well as canned beans in tomato sauce and canned green peas). Conclusion. A highly sensitive specific test-system was developed for dot-immunoassay based on the commercial anti-botulin antibodies labelled with colloid gold particles that allows to detect botulin toxins within 2 hours in the sample volume of 1 - 2 microlites .