INTRODUCTION

Flexible, fast and inexpensive vaccine development and production technologies are needed to prevent the spread of future epidemics and meet the need for vaccination. The purpose of this study was a comparative assessment of two methods of isolation and purification of the main component of plague vaccines — capsule antigen F1.

MATERIALS AND METHODS

To create an expression vector, the caf operon was cloned at the EcoRI site in the pesticinogenicity plasmid pPst of the plague microbe. The constructed plasmid pPKB-F1 was introduced by cryotransformation into the Y. pseudotuberculosis 11M strain. F1 capsule antigen preparations were obtained from the culture liquid by precipitation at the isoelectric point or salting out with ammonium sulfate.

RESULTS

The recombinant strain Y. pseudotuberculosis 11M/pPKB-F1 had the ability to secrete capsular antigen, and the level of production and serological activity of the protein were higher than that of the vaccine strain Y. pestis EV NIIEG. The safety and immunogenicity of the recombinant capsular antigen when administered subcutaneously to mice, as well as protection against infection with massive doses of a virulent strain of the plague microbe, were shown.

CONCLUSION

Y. pseudotuberculosis strain 11M/pPKB-F1 is an effective producer of capsular antigen F1. The highly purified F1 antigen preparation surpasses the preparation isolated at the isoelectric point in protective properties and may be a potential component in the development of a subunit vaccine against plague.