Immunochromatographic test-system for express diagnostics of rabies

Abstract

Relevance. Rabies is included in the group of transmissible viral zooanthroponoses that globally affect public health and the public economy. In Russian Federation, according to the State Standard 26075-2013, the method of virus isolation is a priority for the diagnosis of rabies, followed by detection by the method of fluorescent antibodies (MFA), however, the call of the World Health Organization to abandon research using animals makes it relevant to further develop and improve diagnostic methods in vitro.The purpose of the study. Designing a test system based on immunochromatographic analysis (IHA) for rapid diagnosis of rabies.Methods. Colloidal gold nanoparticles (CGN) with an optimal diameter (25–30 nm) were synthesized by citrate reduction of chloroauric acid and morphometrically characterized by the results of transmission electron microscopy. The conjugation of CGN with anti-rabies antibodies was carried out by non-covalent cross-linking, as a result of which stable conjugates were obtained with an immobilization coefficient of 91.8 ± 1.7%.Results. The classical scheme of direct (sandwich) was used IHA, in which the liquid phase (a sample containing the desired antigen) binds to labeled specific antibodies and, during migration through the solid phase, forms a colored complex with applied specific antibodies in the test zone («sandwich» NCHKZ-antibody — antigen — antibody). ICA was performed with positive, negative and heterologous antigens. The results of the study of samples by ICA were in direct correlation with the results of enzyme-linked immunosorbent assay (ELISA) and MFA and demonstrated 100% specificity. The presented data confirm the functionality of ICA for the detection of rabies virus antigen in pathological material.