[Infectious-toxic model of plague in mice]

Area of Science:

• Microbiology
• Immunology
• Infectious Diseases

Background:

• Plague, caused by Yersinia pestis, remains a significant public health concern.
• Effective vaccine development requires robust models to assess immunogenicity and protection.

Purpose of the Study:

• To establish an infectious-toxic model of plague in mice.
• To evaluate the efficacy of vaccine candidates using this model.

Main Methods:

• Subcutaneous inoculation of mice with activated virulent Yersinia pestis strains (231 and 231 FI-) or conventional suspensions.
• Assessment of virulence (LD50) and protective immunity (immunity index) in naive and immune mice.

Main Results:

• Activated Yersinia pestis cultures exhibited maximal virulence (LD50 = 1-3 CFU), causing rapid, lethal infections.
• The conventional vaccine strain EV induced strong antibacterial immunity, but was overcome by activated Y. pestis 231.
• Y. pestis 231 FI- demonstrated the inability of the EV strain to induce antitoxic immunity.

Conclusions:

• The developed infectious-toxic model provides a more adequate prognosis for vaccine efficacy.
• This model is crucial for selecting and refining new plague vaccine preparations.