Technological Aspects of Constructing an Erythrocyte Immunoglobulin Diagnosticum for the Detection of the Plague Pathogen

Abstract

The aim of the study was to construct an erythrocyte immunoglobulin diagnostic kit for the rapid detection of the plague pathogen (Yersinia pestis) using an indirect hemagglutination assay and to assess its analytical performance. The scientific innovation consisted in developing a new approach to producing an erythrocyte immunoglobulin plague diagnostic kit based on targeted adjustment of pH and surfactant concentration to optimize the interaction of antibodies with formalinized erythrocytes. Materials and methods. The diagnostic preparations were obtained using formalinized sheep erythrocytes conjugated with plague IgG in the presence of sodium lauryl sulfate (SLS). The pH of the medium (4.0…5.0 ± 0.05) and SLS concentration (0.20…0.45 ± 0.001 %) were adjusted to determine the optimal conjugation conditions. Analytical sensitivity and specificity were assessed in IHA using homologous and heterologous microbial strains. Statistical processing was carried out using a two-factor analysis of variance with a significance level of p<0.05. Results and discussion. A significant effect of pH and SLS concentration on the sensitivity of the diagnosticum (p<0.001), as well as their interaction (p<0.001), has been established. The optimal parameters are SLS concentration of (0.21±0.001) % and erythrocyte suspension pH of 4.3±0.05. Under these conditions, the diagnostic preparation demonstrated an analytical sensitivity of (1.95…3.90)·10 5 cells/ml, no cross-reactions with heterologous strains, and stability during one year of storage. The developed technology provides a highly specific, stable, and reproducible preparation suitable for rapid serological detection of plague, which is of practical importance for epidemiological surveillance and laboratory diagnostics of natural-focal particularly dangerous infections.