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Yersinia pestis versus Yersinia pseudotuberculosis: effects on host macrophages
1State Key Laboratory of Pathogen and Biosecurity, National Center for Biomedical Analysis, Army Center for Microbial Detection and Research, Institute of Microbiology and Epidemiology, Beijing, China.
Abstract:
Yersinia pestis, the causative agent of plague, is proved to be a recently emerged clone from Y. pseudotuberculosis. However, the diseases they cause and their patterns of transmission are very different. People always focus on the genetic changes between Y. pestis and Y. pseudotuberculosis to reveal their pathogenic differences, and little is known about host defence differences to these two Yersinia. In this study, the effects of Y. pestis and Y. pseudotuberculosis on macrophages were analysed. Cell apoptosis showed significant difference after the macrophages were infected by these two strains, and caspase-3 activity also demonstrated a similar tendency. Further, macrophage function activities were evaluated. We found during the early infection of Y. pestis, several basic functions of macrophages, including phagocytosis, secretion of cytokine tumour necrosis factor-α and nitric oxide, macrophage polarity and antigen presenting, were significantly interrupted. In comparison, Y. pseudotuberculosis infection showed lower inhibition on macrophages. Especially, Y. pestis infection might cause macrophage to polarize to M2 macrophages in the early phase, compared with Y. pseudotuberculosis infection, which was different from the common acute infection. These results clearly indicated even in the early stage of infection, different host macrophage defence patterns could help us to understand the obvious virulence differences between Y. pestis and Y. pseudotuberculosis.
Insights
Yersinia pestis and Yersinia pseudotuberculosis infections impact host macrophages differently. Y. pestis significantly inhibits macrophage functions early in infection, unlike Y. pseudotuberculosis, revealing key virulence distinctions.
Area of Science:
- * Immunology
- * Microbiology
- * Pathogenesis
Background:
- * Yersinia pestis, the plague pathogen, is a recent clone of Yersinia pseudotuberculosis, yet causes distinct diseases and transmission patterns.
- * Research often focuses on genetic divergence, neglecting host defense differences against these closely related bacteria.
- * Understanding host immune responses, particularly macrophage behavior, is crucial for explaining virulence disparities.
Purpose of the Study:
- * To investigate and compare the effects of Yersinia pestis and Yersinia pseudotuberculosis infections on host macrophages.
- * To elucidate differences in macrophage apoptosis, function, and polarization during early infection stages.
- * To correlate host defense alterations with the distinct virulence of Y. pestis and Y. pseudotuberculosis.
Main Methods:
- * Analysis of macrophage apoptosis and caspase-3 activity following infection with Y. pestis and Y. pseudotuberculosis.
- * Evaluation of key macrophage functions: phagocytosis, cytokine secretion (TNF-α, NO), polarity, and antigen presentation.
- * Comparative assessment of host immune response modulation by the two Yersinia species.
Main Results:
- * Significant differences in macrophage apoptosis and caspase-3 activity were observed between Y. pestis and Y. pseudotuberculosis infections.
- * Early Y. pestis infection markedly impaired macrophage functions, including phagocytosis, cytokine production, and antigen presentation.
- * Y. pestis infection promoted M2 macrophage polarization in the early phase, a distinct response compared to Y. pseudotuberculosis.
Conclusions:
- * Host macrophage defense patterns differ significantly between Y. pestis and Y. pseudotuberculosis infections, even in the early stages.
- * The observed inhibition of macrophage functions by Y. pestis contributes to its higher virulence.
- * Early M2 polarization induced by Y. pestis suggests a novel immune evasion strategy impacting pathogenesis.
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