Immunostimulating effect of <i>Yersinia enterocolitica</i>-antigen conjugated gold nanoparticles

Abstract

Yersinia enterocolitica is the causative agent of yersiniosis, an acute infectious disease of the gastrointestinal tract. Y. enterocolitica is one of the most common causative agents of nosocomial infections. The problem of intestinal yersiniosis caused by Y. enterocolitica is very relevant for medicine and veterinary medicine and requires the use of sero- and immunodiagnostics to identify the causative agent in humans, animals and animal products. One of the most popular nanocarriers of antigens used for immunization and vaccination are gold nanoparticles. The advantages of using gold nanoparticles as vaccine delivery vehicles are their relatively small size, which makes it easy to penetrate tissues, low toxicity and prolonged in vivo circulation, low cost, reproducibility. Currently, using gold nanoparticles, work is underway to create new diagnostic tests and vaccines against viral, bacterial, parasitic infections, including against bacteria of the genus Yersinia. The aim of the study was to study the use of gold nanoparticles as an immunomodulator for immunization and vaccination with an antigen isolated from Y. enterocolitica. The isolated Y. enterocolitica antigen was conjugated to 15 nm gold nanoparticles. The synthesized conjugate was used to immunize laboratory animals. The methods of immunochemical analysis determined the sensitivity and specificity of the antibodies obtained. To establish a protective effect, animals were vaccinated with antigen conjugates and comparison preparations. When animals were immunized with a conjugate of gold nanoparticles with Y. enterocolitica antigen, an antiserum was obtained that specifically recognizes yersiniosis proteins with molecular weights of ~ 35 and ~ 14 kDA in a blot analysis. A cross was detected with bacteria of the species Y. pseudotuberculosis and no cross with the cells of the bacteria of the intestinal group Escherichia coli, Salmonella enterica, Pseudomonas aeruginosa, Proteus vulgaris, which indicates the generic specificity of the antibodies obtained. To determine the protective effect, animals were vaccinated with antigen conjugates with gold nanoparticles and comparison preparations. Two weeks after the last vaccination, mice were injected intraperitoneally with a culture of the pathogenic strain Y. enterocolitica. The groups immunized with a conjugate of antigen with gold nanoparticles showed a survival rate of 70-80%, while the control mice all died. It was shown that conjugates of gold nanoparticles with a yersiniosis antigen have a higher immunomodulating activity compared to unconjugated antigen. The resulting antibodies can be used for effective immunodiagnosis of yersiniosis. Conjugates of gold nanoparticles with antigens of Y. enterocolitica can serve as the basis for creating a preventive vaccine.